Merge pull request #24897 from Microsoft/restTuples

Tuples in rest parameters and spread expressions

src/compiler/binder.ts

@@ -3606,6 +3606,8 @@ namespace ts {
             case SyntaxKind.TypeLiteral:
             case SyntaxKind.ArrayType:
             case SyntaxKind.TupleType:
+            case SyntaxKind.OptionalType:
+            case SyntaxKind.RestType:
             case SyntaxKind.UnionType:
             case SyntaxKind.IntersectionType:
             case SyntaxKind.ConditionalType:

src/compiler/diagnosticMessages.json

@@ -367,10 +367,6 @@
         "category": "Error",
         "code": 1121
     },
-    "A tuple type element list cannot be empty.": {
-        "category": "Error",
-        "code": 1122
-    },
     "Variable declaration list cannot be empty.": {
         "category": "Error",
         "code": 1123
@@ -847,6 +843,14 @@
         "category": "Error",
         "code": 1255
     },
+    "A rest element must be last in a tuple type.": {
+        "category": "Error",
+        "code": 1256
+    },
+    "A required element cannot follow an optional element.": {
+        "category": "Error",
+        "code": 1257
+    },
     "'with' statements are not allowed in an async function block.": {
         "category": "Error",
         "code": 1300
@@ -2032,6 +2036,18 @@
         "category": "Error",
         "code": 2571
     },
+    "Rest signatures are incompatible.": {
+        "category": "Error",
+        "code": 2572
+    },
+    "Property '{0}' is incompatible with rest element type.": {
+        "category": "Error",
+        "code": 2573
+    },
+    "A rest element type must be an array type.": {
+        "category": "Error",
+        "code": 2574
+    },
     "JSX element attributes type '{0}' may not be a union type.": {
         "category": "Error",
         "code": 2600

src/compiler/emitter.ts

@@ -659,6 +659,8 @@ namespace ts {
                         return emitArrayType(<ArrayTypeNode>node);
                     case SyntaxKind.TupleType:
                         return emitTupleType(<TupleTypeNode>node);
+                    case SyntaxKind.OptionalType:
+                        return emitOptionalType(<OptionalTypeNode>node);
                     case SyntaxKind.UnionType:
                         return emitUnionType(<UnionTypeNode>node);
                     case SyntaxKind.IntersectionType:
@@ -695,8 +697,9 @@ namespace ts {
                         return emitJSDocNonNullableType(node as JSDocNonNullableType);
                     case SyntaxKind.JSDocOptionalType:
                         return emitJSDocOptionalType(node as JSDocOptionalType);
+                    case SyntaxKind.RestType:
                     case SyntaxKind.JSDocVariadicType:
-                        return emitJSDocVariadicType(node as JSDocVariadicType);
+                        return emitRestOrJSDocVariadicType(node as RestTypeNode | JSDocVariadicType);
 
                     // Binding patterns
                     case SyntaxKind.ObjectBindingPattern:
@@ -1304,7 +1307,7 @@ namespace ts {
             writePunctuation("]");
         }
 
-        function emitJSDocVariadicType(node: JSDocVariadicType) {
+        function emitRestOrJSDocVariadicType(node: RestTypeNode | JSDocVariadicType) {
             write("...");
             emit(node.type);
         }
@@ -1315,6 +1318,11 @@ namespace ts {
             writePunctuation("]");
         }
 
+        function emitOptionalType(node: OptionalTypeNode) {
+            emit(node.type);
+            write("?");
+        }
+
         function emitUnionType(node: UnionTypeNode) {
             emitList(node, node.types, ListFormat.UnionTypeConstituents);
         }

src/compiler/factory.ts

@@ -745,12 +745,36 @@ namespace ts {
         return node;
     }
 
-    export function updateTypleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>) {
+    export function updateTupleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>) {
         return node.elementTypes !== elementTypes
             ? updateNode(createTupleTypeNode(elementTypes), node)
             : node;
     }
 
+    export function createOptionalTypeNode(type: TypeNode) {
+        const node = createSynthesizedNode(SyntaxKind.OptionalType) as OptionalTypeNode;
+        node.type = parenthesizeArrayTypeMember(type);
+        return node;
+    }
+
+    export function updateOptionalTypeNode(node: OptionalTypeNode, type: TypeNode): OptionalTypeNode {
+        return node.type !== type
+            ? updateNode(createOptionalTypeNode(type), node)
+            : node;
+    }
+
+    export function createRestTypeNode(type: TypeNode) {
+        const node = createSynthesizedNode(SyntaxKind.RestType) as RestTypeNode;
+        node.type = type;
+        return node;
+    }
+
+    export function updateRestTypeNode(node: RestTypeNode, type: TypeNode): RestTypeNode {
+        return node.type !== type
+            ? updateNode(createRestTypeNode(type), node)
+            : node;
+    }
+
     export function createUnionTypeNode(types: ReadonlyArray<TypeNode>): UnionTypeNode {
         return <UnionTypeNode>createUnionOrIntersectionTypeNode(SyntaxKind.UnionType, types);
     }

src/compiler/parser.ts

@@ -445,19 +445,17 @@ namespace ts {
             case SyntaxKind.JsxClosingElement:
                 return visitNode(cbNode, (<JsxClosingElement>node).tagName);
 
+            case SyntaxKind.OptionalType:
+            case SyntaxKind.RestType:
             case SyntaxKind.JSDocTypeExpression:
-                return visitNode(cbNode, (<JSDocTypeExpression>node).type);
             case SyntaxKind.JSDocNonNullableType:
-                return visitNode(cbNode, (<JSDocNonNullableType>node).type);
             case SyntaxKind.JSDocNullableType:
-                return visitNode(cbNode, (<JSDocNullableType>node).type);
             case SyntaxKind.JSDocOptionalType:
-                return visitNode(cbNode, (<JSDocOptionalType>node).type);
+            case SyntaxKind.JSDocVariadicType:
+                return visitNode(cbNode, (<OptionalTypeNode | RestTypeNode | JSDocTypeExpression | JSDocTypeReferencingNode>node).type);
             case SyntaxKind.JSDocFunctionType:
                 return visitNodes(cbNode, cbNodes, (<JSDocFunctionType>node).parameters) ||
                     visitNode(cbNode, (<JSDocFunctionType>node).type);
-            case SyntaxKind.JSDocVariadicType:
-                return visitNode(cbNode, (<JSDocVariadicType>node).type);
             case SyntaxKind.JSDocComment:
                 return visitNodes(cbNode, cbNodes, (<JSDoc>node).tags);
             case SyntaxKind.JSDocParameterTag:
@@ -2289,7 +2287,7 @@ namespace ts {
         function parseJSDocAllType(postFixEquals: boolean): JSDocAllType | JSDocOptionalType {
             const result = createNode(SyntaxKind.JSDocAllType) as JSDocAllType;
             if (postFixEquals) {
-                return createJSDocPostfixType(SyntaxKind.JSDocOptionalType, result) as JSDocOptionalType;
+                return createPostfixType(SyntaxKind.JSDocOptionalType, result) as JSDocOptionalType;
             }
             else {
                 nextToken();
@@ -2367,7 +2365,7 @@ namespace ts {
                 type = finishNode(variadic);
             }
             if (token() === SyntaxKind.EqualsToken) {
-                return createJSDocPostfixType(SyntaxKind.JSDocOptionalType, type);
+                return createPostfixType(SyntaxKind.JSDocOptionalType, type);
             }
             return type;
         }
@@ -2775,9 +2773,23 @@ namespace ts {
             return finishNode(node);
         }
 
+        function parseTupleElementType() {
+            const pos = getNodePos();
+            if (parseOptional(SyntaxKind.DotDotDotToken)) {
+                const node = <RestTypeNode>createNode(SyntaxKind.RestType, pos);
+                node.type = parseType();
+                return finishNode(node);
+            }
+            const type = parseType();
+            if (!(contextFlags & NodeFlags.JSDoc) && type.kind === SyntaxKind.JSDocNullableType && type.pos === (<JSDocNullableType>type).type.pos) {
+                type.kind = SyntaxKind.OptionalType;
+            }
+            return type;
+        }
+
         function parseTupleType(): TupleTypeNode {
             const node = <TupleTypeNode>createNode(SyntaxKind.TupleType);
-            node.elementTypes = parseBracketedList(ParsingContext.TupleElementTypes, parseType, SyntaxKind.OpenBracketToken, SyntaxKind.CloseBracketToken);
+            node.elementTypes = parseBracketedList(ParsingContext.TupleElementTypes, parseTupleElementType, SyntaxKind.OpenBracketToken, SyntaxKind.CloseBracketToken);
             return finishNode(node);
         }
 
@@ -2960,14 +2972,14 @@ namespace ts {
             while (!scanner.hasPrecedingLineBreak()) {
                 switch (token()) {
                     case SyntaxKind.ExclamationToken:
-                        type = createJSDocPostfixType(SyntaxKind.JSDocNonNullableType, type);
+                        type = createPostfixType(SyntaxKind.JSDocNonNullableType, type);
                         break;
                     case SyntaxKind.QuestionToken:
                         // If not in JSDoc and next token is start of a type we have a conditional type
                         if (!(contextFlags & NodeFlags.JSDoc) && lookAhead(nextTokenIsStartOfType)) {
                             return type;
                         }
-                        type = createJSDocPostfixType(SyntaxKind.JSDocNullableType, type);
+                        type = createPostfixType(SyntaxKind.JSDocNullableType, type);
                         break;
                     case SyntaxKind.OpenBracketToken:
                         parseExpected(SyntaxKind.OpenBracketToken);
@@ -2992,9 +3004,9 @@ namespace ts {
             return type;
         }
 
-        function createJSDocPostfixType(kind: SyntaxKind, type: TypeNode) {
+        function createPostfixType(kind: SyntaxKind, type: TypeNode) {
             nextToken();
-            const postfix = createNode(kind, type.pos) as JSDocOptionalType | JSDocNonNullableType | JSDocNullableType;
+            const postfix = createNode(kind, type.pos) as OptionalTypeNode | JSDocOptionalType | JSDocNonNullableType | JSDocNullableType;
             postfix.type = type;
             return finishNode(postfix);
         }

src/compiler/transformers/ts.ts

@@ -380,6 +380,8 @@ namespace ts {
 
                 case SyntaxKind.ArrayType:
                 case SyntaxKind.TupleType:
+                case SyntaxKind.OptionalType:
+                case SyntaxKind.RestType:
                 case SyntaxKind.TypeLiteral:
                 case SyntaxKind.TypePredicate:
                 case SyntaxKind.TypeParameter:

src/compiler/types.ts

@@ -225,6 +225,8 @@ namespace ts {
         TypeLiteral,
         ArrayType,
         TupleType,
+        OptionalType,
+        RestType,
         UnionType,
         IntersectionType,
         ConditionalType,
@@ -269,6 +271,7 @@ namespace ts {
         AsExpression,
         NonNullExpression,
         MetaProperty,
+        SyntheticExpression,
 
         // Misc
         TemplateSpan,
@@ -1101,6 +1104,16 @@ namespace ts {
         elementTypes: NodeArray<TypeNode>;
     }
 
+    export interface OptionalTypeNode extends TypeNode {
+        kind: SyntaxKind.OptionalType;
+        type: TypeNode;
+    }
+
+    export interface RestTypeNode extends TypeNode {
+        kind: SyntaxKind.RestType;
+        type: TypeNode;
+    }
+
     export type UnionOrIntersectionTypeNode = UnionTypeNode | IntersectionTypeNode;
 
     export interface UnionTypeNode extends TypeNode {
@@ -1288,6 +1301,12 @@ namespace ts {
         expression?: Expression;
     }
 
+    export interface SyntheticExpression extends Expression {
+        kind: SyntaxKind.SyntheticExpression;
+        isSpread: boolean;
+        type: Type;
+    }
+
     // see: https://tc39.github.io/ecma262/#prod-ExponentiationExpression
     export type ExponentiationOperator
         = SyntaxKind.AsteriskAsteriskToken
@@ -3521,14 +3540,15 @@ namespace ts {
         ContainsPrivate   = 1 << 8,         // Synthetic property with private constituent(s)
         ContainsStatic    = 1 << 9,         // Synthetic property with static constituent(s)
         Late              = 1 << 10,        // Late-bound symbol for a computed property with a dynamic name
-        ReverseMapped     = 1 << 11,        // property of reverse-inferred homomorphic mapped type.
+        ReverseMapped     = 1 << 11,        // Property of reverse-inferred homomorphic mapped type
+        OptionalParameter = 1 << 12,        // Optional parameter
+        RestParameter     = 1 << 13,        // Rest parameter
         Synthetic = SyntheticProperty | SyntheticMethod
     }
 
     /* @internal */
     export interface TransientSymbol extends Symbol, SymbolLinks {
         checkFlags: CheckFlags;
-        isRestParameter?: boolean;
     }
 
     /* @internal */
@@ -3857,6 +3877,16 @@ namespace ts {
         variances?: Variance[];  // Variance of each type parameter
     }
 
+    export interface TupleType extends GenericType {
+        minLength: number;
+        hasRestElement: boolean;
+        associatedNames?: __String[];
+    }
+
+    export interface TupleTypeReference extends TypeReference {
+        target: TupleType;
+    }
+
     export interface UnionOrIntersectionType extends Type {
         types: Type[];                    // Constituent types
         /* @internal */

src/compiler/visitor.ts

@@ -372,9 +372,17 @@ namespace ts {
                     visitNode((<ArrayTypeNode>node).elementType, visitor, isTypeNode));
 
             case SyntaxKind.TupleType:
-                return updateTypleTypeNode((<TupleTypeNode>node),
+                return updateTupleTypeNode((<TupleTypeNode>node),
                     nodesVisitor((<TupleTypeNode>node).elementTypes, visitor, isTypeNode));
 
+            case SyntaxKind.OptionalType:
+                return updateOptionalTypeNode((<OptionalTypeNode>node),
+                    visitNode((<OptionalTypeNode>node).type, visitor, isTypeNode));
+
+            case SyntaxKind.RestType:
+                return updateRestTypeNode((<RestTypeNode>node),
+                    visitNode((<RestTypeNode>node).type, visitor, isTypeNode));
+
             case SyntaxKind.UnionType:
                 return updateUnionTypeNode(<UnionTypeNode>node,
                     nodesVisitor((<UnionTypeNode>node).types, visitor, isTypeNode));

tests/baselines/reference/TupleType3.errors.txt

@@ -1,7 +0,0 @@
-tests/cases/conformance/parser/ecmascript5/TupleTypes/TupleType3.ts(1,8): error TS1122: A tuple type element list cannot be empty.
-
-
-==== tests/cases/conformance/parser/ecmascript5/TupleTypes/TupleType3.ts (1 errors) ====
-    var v: []
-           ~~
-!!! error TS1122: A tuple type element list cannot be empty.

tests/baselines/reference/anyIndexedAccessArrayNoException.errors.txt

@@ -1,11 +1,8 @@
-tests/cases/compiler/anyIndexedAccessArrayNoException.ts(1,12): error TS1122: A tuple type element list cannot be empty.
 tests/cases/compiler/anyIndexedAccessArrayNoException.ts(1,12): error TS2538: Type '[]' cannot be used as an index type.
 
 
-==== tests/cases/compiler/anyIndexedAccessArrayNoException.ts (2 errors) ====
+==== tests/cases/compiler/anyIndexedAccessArrayNoException.ts (1 errors) ====
     var x: any[[]];
                ~~
-!!! error TS1122: A tuple type element list cannot be empty.
-               ~~
 !!! error TS2538: Type '[]' cannot be used as an index type.
     

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -746,144 +746,147 @@ declare namespace ts {
         TypeLiteral = 166,
         ArrayType = 167,
         TupleType = 168,
-        UnionType = 169,
-        IntersectionType = 170,
-        ConditionalType = 171,
-        InferType = 172,
-        ParenthesizedType = 173,
-        ThisType = 174,
-        TypeOperator = 175,
-        IndexedAccessType = 176,
-        MappedType = 177,
-        LiteralType = 178,
-        ImportType = 179,
-        ObjectBindingPattern = 180,
-        ArrayBindingPattern = 181,
-        BindingElement = 182,
-        ArrayLiteralExpression = 183,
-        ObjectLiteralExpression = 184,
-        PropertyAccessExpression = 185,
-        ElementAccessExpression = 186,
-        CallExpression = 187,
-        NewExpression = 188,
-        TaggedTemplateExpression = 189,
-        TypeAssertionExpression = 190,
-        ParenthesizedExpression = 191,
-        FunctionExpression = 192,
-        ArrowFunction = 193,
-        DeleteExpression = 194,
-        TypeOfExpression = 195,
-        VoidExpression = 196,
-        AwaitExpression = 197,
-        PrefixUnaryExpression = 198,
-        PostfixUnaryExpression = 199,
-        BinaryExpression = 200,
-        ConditionalExpression = 201,
-        TemplateExpression = 202,
-        YieldExpression = 203,
-        SpreadElement = 204,
-        ClassExpression = 205,
-        OmittedExpression = 206,
-        ExpressionWithTypeArguments = 207,
-        AsExpression = 208,
-        NonNullExpression = 209,
-        MetaProperty = 210,
-        TemplateSpan = 211,
-        SemicolonClassElement = 212,
-        Block = 213,
-        VariableStatement = 214,
-        EmptyStatement = 215,
-        ExpressionStatement = 216,
-        IfStatement = 217,
-        DoStatement = 218,
-        WhileStatement = 219,
-        ForStatement = 220,
-        ForInStatement = 221,
-        ForOfStatement = 222,
-        ContinueStatement = 223,
-        BreakStatement = 224,
-        ReturnStatement = 225,
-        WithStatement = 226,
-        SwitchStatement = 227,
-        LabeledStatement = 228,
-        ThrowStatement = 229,
-        TryStatement = 230,
-        DebuggerStatement = 231,
-        VariableDeclaration = 232,
-        VariableDeclarationList = 233,
-        FunctionDeclaration = 234,
-        ClassDeclaration = 235,
-        InterfaceDeclaration = 236,
-        TypeAliasDeclaration = 237,
-        EnumDeclaration = 238,
-        ModuleDeclaration = 239,
-        ModuleBlock = 240,
-        CaseBlock = 241,
-        NamespaceExportDeclaration = 242,
-        ImportEqualsDeclaration = 243,
-        ImportDeclaration = 244,
-        ImportClause = 245,
-        NamespaceImport = 246,
-        NamedImports = 247,
-        ImportSpecifier = 248,
-        ExportAssignment = 249,
-        ExportDeclaration = 250,
-        NamedExports = 251,
-        ExportSpecifier = 252,
-        MissingDeclaration = 253,
-        ExternalModuleReference = 254,
-        JsxElement = 255,
-        JsxSelfClosingElement = 256,
-        JsxOpeningElement = 257,
-        JsxClosingElement = 258,
-        JsxFragment = 259,
-        JsxOpeningFragment = 260,
-        JsxClosingFragment = 261,
-        JsxAttribute = 262,
-        JsxAttributes = 263,
-        JsxSpreadAttribute = 264,
-        JsxExpression = 265,
-        CaseClause = 266,
-        DefaultClause = 267,
-        HeritageClause = 268,
-        CatchClause = 269,
-        PropertyAssignment = 270,
-        ShorthandPropertyAssignment = 271,
-        SpreadAssignment = 272,
-        EnumMember = 273,
-        SourceFile = 274,
-        Bundle = 275,
-        UnparsedSource = 276,
-        InputFiles = 277,
-        JSDocTypeExpression = 278,
-        JSDocAllType = 279,
-        JSDocUnknownType = 280,
-        JSDocNullableType = 281,
-        JSDocNonNullableType = 282,
-        JSDocOptionalType = 283,
-        JSDocFunctionType = 284,
-        JSDocVariadicType = 285,
-        JSDocComment = 286,
-        JSDocTypeLiteral = 287,
-        JSDocSignature = 288,
-        JSDocTag = 289,
-        JSDocAugmentsTag = 290,
-        JSDocClassTag = 291,
-        JSDocCallbackTag = 292,
-        JSDocParameterTag = 293,
-        JSDocReturnTag = 294,
-        JSDocThisTag = 295,
-        JSDocTypeTag = 296,
-        JSDocTemplateTag = 297,
-        JSDocTypedefTag = 298,
-        JSDocPropertyTag = 299,
-        SyntaxList = 300,
-        NotEmittedStatement = 301,
-        PartiallyEmittedExpression = 302,
-        CommaListExpression = 303,
-        MergeDeclarationMarker = 304,
-        EndOfDeclarationMarker = 305,
-        Count = 306,
+        OptionalType = 169,
+        RestType = 170,
+        UnionType = 171,
+        IntersectionType = 172,
+        ConditionalType = 173,
+        InferType = 174,
+        ParenthesizedType = 175,
+        ThisType = 176,
+        TypeOperator = 177,
+        IndexedAccessType = 178,
+        MappedType = 179,
+        LiteralType = 180,
+        ImportType = 181,
+        ObjectBindingPattern = 182,
+        ArrayBindingPattern = 183,
+        BindingElement = 184,
+        ArrayLiteralExpression = 185,
+        ObjectLiteralExpression = 186,
+        PropertyAccessExpression = 187,
+        ElementAccessExpression = 188,
+        CallExpression = 189,
+        NewExpression = 190,
+        TaggedTemplateExpression = 191,
+        TypeAssertionExpression = 192,
+        ParenthesizedExpression = 193,
+        FunctionExpression = 194,
+        ArrowFunction = 195,
+        DeleteExpression = 196,
+        TypeOfExpression = 197,
+        VoidExpression = 198,
+        AwaitExpression = 199,
+        PrefixUnaryExpression = 200,
+        PostfixUnaryExpression = 201,
+        BinaryExpression = 202,
+        ConditionalExpression = 203,
+        TemplateExpression = 204,
+        YieldExpression = 205,
+        SpreadElement = 206,
+        ClassExpression = 207,
+        OmittedExpression = 208,
+        ExpressionWithTypeArguments = 209,
+        AsExpression = 210,
+        NonNullExpression = 211,
+        MetaProperty = 212,
+        SyntheticExpression = 213,
+        TemplateSpan = 214,
+        SemicolonClassElement = 215,
+        Block = 216,
+        VariableStatement = 217,
+        EmptyStatement = 218,
+        ExpressionStatement = 219,
+        IfStatement = 220,
+        DoStatement = 221,
+        WhileStatement = 222,
+        ForStatement = 223,
+        ForInStatement = 224,
+        ForOfStatement = 225,
+        ContinueStatement = 226,
+        BreakStatement = 227,
+        ReturnStatement = 228,
+        WithStatement = 229,
+        SwitchStatement = 230,
+        LabeledStatement = 231,
+        ThrowStatement = 232,
+        TryStatement = 233,
+        DebuggerStatement = 234,
+        VariableDeclaration = 235,
+        VariableDeclarationList = 236,
+        FunctionDeclaration = 237,
+        ClassDeclaration = 238,
+        InterfaceDeclaration = 239,
+        TypeAliasDeclaration = 240,
+        EnumDeclaration = 241,
+        ModuleDeclaration = 242,
+        ModuleBlock = 243,
+        CaseBlock = 244,
+        NamespaceExportDeclaration = 245,
+        ImportEqualsDeclaration = 246,
+        ImportDeclaration = 247,
+        ImportClause = 248,
+        NamespaceImport = 249,
+        NamedImports = 250,
+        ImportSpecifier = 251,
+        ExportAssignment = 252,
+        ExportDeclaration = 253,
+        NamedExports = 254,
+        ExportSpecifier = 255,
+        MissingDeclaration = 256,
+        ExternalModuleReference = 257,
+        JsxElement = 258,
+        JsxSelfClosingElement = 259,
+        JsxOpeningElement = 260,
+        JsxClosingElement = 261,
+        JsxFragment = 262,
+        JsxOpeningFragment = 263,
+        JsxClosingFragment = 264,
+        JsxAttribute = 265,
+        JsxAttributes = 266,
+        JsxSpreadAttribute = 267,
+        JsxExpression = 268,
+        CaseClause = 269,
+        DefaultClause = 270,
+        HeritageClause = 271,
+        CatchClause = 272,
+        PropertyAssignment = 273,
+        ShorthandPropertyAssignment = 274,
+        SpreadAssignment = 275,
+        EnumMember = 276,
+        SourceFile = 277,
+        Bundle = 278,
+        UnparsedSource = 279,
+        InputFiles = 280,
+        JSDocTypeExpression = 281,
+        JSDocAllType = 282,
+        JSDocUnknownType = 283,
+        JSDocNullableType = 284,
+        JSDocNonNullableType = 285,
+        JSDocOptionalType = 286,
+        JSDocFunctionType = 287,
+        JSDocVariadicType = 288,
+        JSDocComment = 289,
+        JSDocTypeLiteral = 290,
+        JSDocSignature = 291,
+        JSDocTag = 292,
+        JSDocAugmentsTag = 293,
+        JSDocClassTag = 294,
+        JSDocCallbackTag = 295,
+        JSDocParameterTag = 296,
+        JSDocReturnTag = 297,
+        JSDocThisTag = 298,
+        JSDocTypeTag = 299,
+        JSDocTemplateTag = 300,
+        JSDocTypedefTag = 301,
+        JSDocPropertyTag = 302,
+        SyntaxList = 303,
+        NotEmittedStatement = 304,
+        PartiallyEmittedExpression = 305,
+        CommaListExpression = 306,
+        MergeDeclarationMarker = 307,
+        EndOfDeclarationMarker = 308,
+        Count = 309,
         FirstAssignment = 58,
         LastAssignment = 70,
         FirstCompoundAssignment = 59,
@@ -895,7 +898,7 @@ declare namespace ts {
         FirstFutureReservedWord = 108,
         LastFutureReservedWord = 116,
         FirstTypeNode = 161,
-        LastTypeNode = 179,
+        LastTypeNode = 181,
         FirstPunctuation = 17,
         LastPunctuation = 70,
         FirstToken = 0,
@@ -909,10 +912,10 @@ declare namespace ts {
         FirstBinaryOperator = 27,
         LastBinaryOperator = 70,
         FirstNode = 146,
-        FirstJSDocNode = 278,
-        LastJSDocNode = 299,
-        FirstJSDocTagNode = 289,
-        LastJSDocTagNode = 299,
+        FirstJSDocNode = 281,
+        LastJSDocNode = 302,
+        FirstJSDocTagNode = 292,
+        LastJSDocTagNode = 302,
         FirstContextualKeyword = 117,
         LastContextualKeyword = 145
     }
@@ -1335,6 +1338,14 @@ declare namespace ts {
         kind: SyntaxKind.TupleType;
         elementTypes: NodeArray<TypeNode>;
     }
+    interface OptionalTypeNode extends TypeNode {
+        kind: SyntaxKind.OptionalType;
+        type: TypeNode;
+    }
+    interface RestTypeNode extends TypeNode {
+        kind: SyntaxKind.RestType;
+        type: TypeNode;
+    }
     type UnionOrIntersectionTypeNode = UnionTypeNode | IntersectionTypeNode;
     interface UnionTypeNode extends TypeNode {
         kind: SyntaxKind.UnionType;
@@ -1465,6 +1476,11 @@ declare namespace ts {
         asteriskToken?: AsteriskToken;
         expression?: Expression;
     }
+    interface SyntheticExpression extends Expression {
+        kind: SyntaxKind.SyntheticExpression;
+        isSpread: boolean;
+        type: Type;
+    }
     type ExponentiationOperator = SyntaxKind.AsteriskAsteriskToken;
     type MultiplicativeOperator = SyntaxKind.AsteriskToken | SyntaxKind.SlashToken | SyntaxKind.PercentToken;
     type MultiplicativeOperatorOrHigher = ExponentiationOperator | MultiplicativeOperator;
@@ -3074,11 +3090,12 @@ declare namespace ts {
         ContainsStatic = 512,
         Late = 1024,
         ReverseMapped = 2048,
+        OptionalParameter = 4096,
+        RestParameter = 8192,
         Synthetic = 6
     }
     interface TransientSymbol extends Symbol, SymbolLinks {
         checkFlags: CheckFlags;
-        isRestParameter?: boolean;
     }
     interface ReverseMappedSymbol extends TransientSymbol {
         propertyType: Type;
@@ -3338,6 +3355,14 @@ declare namespace ts {
         instantiations: Map<TypeReference>;
         variances?: Variance[];
     }
+    interface TupleType extends GenericType {
+        minLength: number;
+        hasRestElement: boolean;
+        associatedNames?: __String[];
+    }
+    interface TupleTypeReference extends TypeReference {
+        target: TupleType;
+    }
     interface UnionOrIntersectionType extends Type {
         types: Type[];
         propertyCache: SymbolTable;
@@ -4905,7 +4930,6 @@ declare namespace ts {
         An_object_literal_cannot_have_property_and_accessor_with_the_same_name: DiagnosticMessage;
         An_export_assignment_cannot_have_modifiers: DiagnosticMessage;
         Octal_literals_are_not_allowed_in_strict_mode: DiagnosticMessage;
-        A_tuple_type_element_list_cannot_be_empty: DiagnosticMessage;
         Variable_declaration_list_cannot_be_empty: DiagnosticMessage;
         Digit_expected: DiagnosticMessage;
         Hexadecimal_digit_expected: DiagnosticMessage;
@@ -5025,6 +5049,8 @@ declare namespace ts {
         _0_tag_cannot_be_used_independently_as_a_top_level_JSDoc_tag: DiagnosticMessage;
         A_const_initializer_in_an_ambient_context_must_be_a_string_or_numeric_literal: DiagnosticMessage;
         A_definite_assignment_assertion_is_not_permitted_in_this_context: DiagnosticMessage;
+        A_rest_element_must_be_last_in_a_tuple_type: DiagnosticMessage;
+        A_required_element_cannot_follow_an_optional_element: DiagnosticMessage;
         with_statements_are_not_allowed_in_an_async_function_block: DiagnosticMessage;
         await_expression_is_only_allowed_within_an_async_function: DiagnosticMessage;
         can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment: DiagnosticMessage;
@@ -5321,6 +5347,9 @@ declare namespace ts {
         Type_0_is_not_an_array_type_or_a_string_type_Use_compiler_option_downlevelIteration_to_allow_iterating_of_iterators: DiagnosticMessage;
         Property_0_does_not_exist_on_type_1_Did_you_forget_to_use_await: DiagnosticMessage;
         Object_is_of_type_unknown: DiagnosticMessage;
+        Rest_signatures_are_incompatible: DiagnosticMessage;
+        Property_0_is_incompatible_with_rest_element_type: DiagnosticMessage;
+        A_rest_element_type_must_be_an_array_type: DiagnosticMessage;
         JSX_element_attributes_type_0_may_not_be_a_union_type: DiagnosticMessage;
         The_return_type_of_a_JSX_element_constructor_must_return_an_object_type: DiagnosticMessage;
         JSX_element_implicitly_has_type_any_because_the_global_type_JSX_Element_does_not_exist: DiagnosticMessage;
@@ -7779,7 +7808,11 @@ declare namespace ts {
     function createArrayTypeNode(elementType: TypeNode): ArrayTypeNode;
     function updateArrayTypeNode(node: ArrayTypeNode, elementType: TypeNode): ArrayTypeNode;
     function createTupleTypeNode(elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
-    function updateTypleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
+    function updateTupleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
+    function createOptionalTypeNode(type: TypeNode): OptionalTypeNode;
+    function updateOptionalTypeNode(node: OptionalTypeNode, type: TypeNode): OptionalTypeNode;
+    function createRestTypeNode(type: TypeNode): RestTypeNode;
+    function updateRestTypeNode(node: RestTypeNode, type: TypeNode): RestTypeNode;
     function createUnionTypeNode(types: ReadonlyArray<TypeNode>): UnionTypeNode;
     function updateUnionTypeNode(node: UnionTypeNode, types: NodeArray<TypeNode>): UnionTypeNode;
     function createIntersectionTypeNode(types: ReadonlyArray<TypeNode>): IntersectionTypeNode;

tests/baselines/reference/api/typescript.d.ts

@@ -226,144 +226,147 @@ declare namespace ts {
         TypeLiteral = 166,
         ArrayType = 167,
         TupleType = 168,
-        UnionType = 169,
-        IntersectionType = 170,
-        ConditionalType = 171,
-        InferType = 172,
-        ParenthesizedType = 173,
-        ThisType = 174,
-        TypeOperator = 175,
-        IndexedAccessType = 176,
-        MappedType = 177,
-        LiteralType = 178,
-        ImportType = 179,
-        ObjectBindingPattern = 180,
-        ArrayBindingPattern = 181,
-        BindingElement = 182,
-        ArrayLiteralExpression = 183,
-        ObjectLiteralExpression = 184,
-        PropertyAccessExpression = 185,
-        ElementAccessExpression = 186,
-        CallExpression = 187,
-        NewExpression = 188,
-        TaggedTemplateExpression = 189,
-        TypeAssertionExpression = 190,
-        ParenthesizedExpression = 191,
-        FunctionExpression = 192,
-        ArrowFunction = 193,
-        DeleteExpression = 194,
-        TypeOfExpression = 195,
-        VoidExpression = 196,
-        AwaitExpression = 197,
-        PrefixUnaryExpression = 198,
-        PostfixUnaryExpression = 199,
-        BinaryExpression = 200,
-        ConditionalExpression = 201,
-        TemplateExpression = 202,
-        YieldExpression = 203,
-        SpreadElement = 204,
-        ClassExpression = 205,
-        OmittedExpression = 206,
-        ExpressionWithTypeArguments = 207,
-        AsExpression = 208,
-        NonNullExpression = 209,
-        MetaProperty = 210,
-        TemplateSpan = 211,
-        SemicolonClassElement = 212,
-        Block = 213,
-        VariableStatement = 214,
-        EmptyStatement = 215,
-        ExpressionStatement = 216,
-        IfStatement = 217,
-        DoStatement = 218,
-        WhileStatement = 219,
-        ForStatement = 220,
-        ForInStatement = 221,
-        ForOfStatement = 222,
-        ContinueStatement = 223,
-        BreakStatement = 224,
-        ReturnStatement = 225,
-        WithStatement = 226,
-        SwitchStatement = 227,
-        LabeledStatement = 228,
-        ThrowStatement = 229,
-        TryStatement = 230,
-        DebuggerStatement = 231,
-        VariableDeclaration = 232,
-        VariableDeclarationList = 233,
-        FunctionDeclaration = 234,
-        ClassDeclaration = 235,
-        InterfaceDeclaration = 236,
-        TypeAliasDeclaration = 237,
-        EnumDeclaration = 238,
-        ModuleDeclaration = 239,
-        ModuleBlock = 240,
-        CaseBlock = 241,
-        NamespaceExportDeclaration = 242,
-        ImportEqualsDeclaration = 243,
-        ImportDeclaration = 244,
-        ImportClause = 245,
-        NamespaceImport = 246,
-        NamedImports = 247,
-        ImportSpecifier = 248,
-        ExportAssignment = 249,
-        ExportDeclaration = 250,
-        NamedExports = 251,
-        ExportSpecifier = 252,
-        MissingDeclaration = 253,
-        ExternalModuleReference = 254,
-        JsxElement = 255,
-        JsxSelfClosingElement = 256,
-        JsxOpeningElement = 257,
-        JsxClosingElement = 258,
-        JsxFragment = 259,
-        JsxOpeningFragment = 260,
-        JsxClosingFragment = 261,
-        JsxAttribute = 262,
-        JsxAttributes = 263,
-        JsxSpreadAttribute = 264,
-        JsxExpression = 265,
-        CaseClause = 266,
-        DefaultClause = 267,
-        HeritageClause = 268,
-        CatchClause = 269,
-        PropertyAssignment = 270,
-        ShorthandPropertyAssignment = 271,
-        SpreadAssignment = 272,
-        EnumMember = 273,
-        SourceFile = 274,
-        Bundle = 275,
-        UnparsedSource = 276,
-        InputFiles = 277,
-        JSDocTypeExpression = 278,
-        JSDocAllType = 279,
-        JSDocUnknownType = 280,
-        JSDocNullableType = 281,
-        JSDocNonNullableType = 282,
-        JSDocOptionalType = 283,
-        JSDocFunctionType = 284,
-        JSDocVariadicType = 285,
-        JSDocComment = 286,
-        JSDocTypeLiteral = 287,
-        JSDocSignature = 288,
-        JSDocTag = 289,
-        JSDocAugmentsTag = 290,
-        JSDocClassTag = 291,
-        JSDocCallbackTag = 292,
-        JSDocParameterTag = 293,
-        JSDocReturnTag = 294,
-        JSDocThisTag = 295,
-        JSDocTypeTag = 296,
-        JSDocTemplateTag = 297,
-        JSDocTypedefTag = 298,
-        JSDocPropertyTag = 299,
-        SyntaxList = 300,
-        NotEmittedStatement = 301,
-        PartiallyEmittedExpression = 302,
-        CommaListExpression = 303,
-        MergeDeclarationMarker = 304,
-        EndOfDeclarationMarker = 305,
-        Count = 306,
+        OptionalType = 169,
+        RestType = 170,
+        UnionType = 171,
+        IntersectionType = 172,
+        ConditionalType = 173,
+        InferType = 174,
+        ParenthesizedType = 175,
+        ThisType = 176,
+        TypeOperator = 177,
+        IndexedAccessType = 178,
+        MappedType = 179,
+        LiteralType = 180,
+        ImportType = 181,
+        ObjectBindingPattern = 182,
+        ArrayBindingPattern = 183,
+        BindingElement = 184,
+        ArrayLiteralExpression = 185,
+        ObjectLiteralExpression = 186,
+        PropertyAccessExpression = 187,
+        ElementAccessExpression = 188,
+        CallExpression = 189,
+        NewExpression = 190,
+        TaggedTemplateExpression = 191,
+        TypeAssertionExpression = 192,
+        ParenthesizedExpression = 193,
+        FunctionExpression = 194,
+        ArrowFunction = 195,
+        DeleteExpression = 196,
+        TypeOfExpression = 197,
+        VoidExpression = 198,
+        AwaitExpression = 199,
+        PrefixUnaryExpression = 200,
+        PostfixUnaryExpression = 201,
+        BinaryExpression = 202,
+        ConditionalExpression = 203,
+        TemplateExpression = 204,
+        YieldExpression = 205,
+        SpreadElement = 206,
+        ClassExpression = 207,
+        OmittedExpression = 208,
+        ExpressionWithTypeArguments = 209,
+        AsExpression = 210,
+        NonNullExpression = 211,
+        MetaProperty = 212,
+        SyntheticExpression = 213,
+        TemplateSpan = 214,
+        SemicolonClassElement = 215,
+        Block = 216,
+        VariableStatement = 217,
+        EmptyStatement = 218,
+        ExpressionStatement = 219,
+        IfStatement = 220,
+        DoStatement = 221,
+        WhileStatement = 222,
+        ForStatement = 223,
+        ForInStatement = 224,
+        ForOfStatement = 225,
+        ContinueStatement = 226,
+        BreakStatement = 227,
+        ReturnStatement = 228,
+        WithStatement = 229,
+        SwitchStatement = 230,
+        LabeledStatement = 231,
+        ThrowStatement = 232,
+        TryStatement = 233,
+        DebuggerStatement = 234,
+        VariableDeclaration = 235,
+        VariableDeclarationList = 236,
+        FunctionDeclaration = 237,
+        ClassDeclaration = 238,
+        InterfaceDeclaration = 239,
+        TypeAliasDeclaration = 240,
+        EnumDeclaration = 241,
+        ModuleDeclaration = 242,
+        ModuleBlock = 243,
+        CaseBlock = 244,
+        NamespaceExportDeclaration = 245,
+        ImportEqualsDeclaration = 246,
+        ImportDeclaration = 247,
+        ImportClause = 248,
+        NamespaceImport = 249,
+        NamedImports = 250,
+        ImportSpecifier = 251,
+        ExportAssignment = 252,
+        ExportDeclaration = 253,
+        NamedExports = 254,
+        ExportSpecifier = 255,
+        MissingDeclaration = 256,
+        ExternalModuleReference = 257,
+        JsxElement = 258,
+        JsxSelfClosingElement = 259,
+        JsxOpeningElement = 260,
+        JsxClosingElement = 261,
+        JsxFragment = 262,
+        JsxOpeningFragment = 263,
+        JsxClosingFragment = 264,
+        JsxAttribute = 265,
+        JsxAttributes = 266,
+        JsxSpreadAttribute = 267,
+        JsxExpression = 268,
+        CaseClause = 269,
+        DefaultClause = 270,
+        HeritageClause = 271,
+        CatchClause = 272,
+        PropertyAssignment = 273,
+        ShorthandPropertyAssignment = 274,
+        SpreadAssignment = 275,
+        EnumMember = 276,
+        SourceFile = 277,
+        Bundle = 278,
+        UnparsedSource = 279,
+        InputFiles = 280,
+        JSDocTypeExpression = 281,
+        JSDocAllType = 282,
+        JSDocUnknownType = 283,
+        JSDocNullableType = 284,
+        JSDocNonNullableType = 285,
+        JSDocOptionalType = 286,
+        JSDocFunctionType = 287,
+        JSDocVariadicType = 288,
+        JSDocComment = 289,
+        JSDocTypeLiteral = 290,
+        JSDocSignature = 291,
+        JSDocTag = 292,
+        JSDocAugmentsTag = 293,
+        JSDocClassTag = 294,
+        JSDocCallbackTag = 295,
+        JSDocParameterTag = 296,
+        JSDocReturnTag = 297,
+        JSDocThisTag = 298,
+        JSDocTypeTag = 299,
+        JSDocTemplateTag = 300,
+        JSDocTypedefTag = 301,
+        JSDocPropertyTag = 302,
+        SyntaxList = 303,
+        NotEmittedStatement = 304,
+        PartiallyEmittedExpression = 305,
+        CommaListExpression = 306,
+        MergeDeclarationMarker = 307,
+        EndOfDeclarationMarker = 308,
+        Count = 309,
         FirstAssignment = 58,
         LastAssignment = 70,
         FirstCompoundAssignment = 59,
@@ -375,7 +378,7 @@ declare namespace ts {
         FirstFutureReservedWord = 108,
         LastFutureReservedWord = 116,
         FirstTypeNode = 161,
-        LastTypeNode = 179,
+        LastTypeNode = 181,
         FirstPunctuation = 17,
         LastPunctuation = 70,
         FirstToken = 0,
@@ -389,10 +392,10 @@ declare namespace ts {
         FirstBinaryOperator = 27,
         LastBinaryOperator = 70,
         FirstNode = 146,
-        FirstJSDocNode = 278,
-        LastJSDocNode = 299,
-        FirstJSDocTagNode = 289,
-        LastJSDocTagNode = 299
+        FirstJSDocNode = 281,
+        LastJSDocNode = 302,
+        FirstJSDocTagNode = 292,
+        LastJSDocTagNode = 302
     }
     enum NodeFlags {
         None = 0,
@@ -751,6 +754,14 @@ declare namespace ts {
         kind: SyntaxKind.TupleType;
         elementTypes: NodeArray<TypeNode>;
     }
+    interface OptionalTypeNode extends TypeNode {
+        kind: SyntaxKind.OptionalType;
+        type: TypeNode;
+    }
+    interface RestTypeNode extends TypeNode {
+        kind: SyntaxKind.RestType;
+        type: TypeNode;
+    }
     type UnionOrIntersectionTypeNode = UnionTypeNode | IntersectionTypeNode;
     interface UnionTypeNode extends TypeNode {
         kind: SyntaxKind.UnionType;
@@ -875,6 +886,11 @@ declare namespace ts {
         asteriskToken?: AsteriskToken;
         expression?: Expression;
     }
+    interface SyntheticExpression extends Expression {
+        kind: SyntaxKind.SyntheticExpression;
+        isSpread: boolean;
+        type: Type;
+    }
     type ExponentiationOperator = SyntaxKind.AsteriskAsteriskToken;
     type MultiplicativeOperator = SyntaxKind.AsteriskToken | SyntaxKind.SlashToken | SyntaxKind.PercentToken;
     type MultiplicativeOperatorOrHigher = ExponentiationOperator | MultiplicativeOperator;
@@ -2267,6 +2283,14 @@ declare namespace ts {
     }
     interface GenericType extends InterfaceType, TypeReference {
     }
+    interface TupleType extends GenericType {
+        minLength: number;
+        hasRestElement: boolean;
+        associatedNames?: __String[];
+    }
+    interface TupleTypeReference extends TypeReference {
+        target: TupleType;
+    }
     interface UnionOrIntersectionType extends Type {
         types: Type[];
     }
@@ -3694,7 +3718,11 @@ declare namespace ts {
     function createArrayTypeNode(elementType: TypeNode): ArrayTypeNode;
     function updateArrayTypeNode(node: ArrayTypeNode, elementType: TypeNode): ArrayTypeNode;
     function createTupleTypeNode(elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
-    function updateTypleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
+    function updateTupleTypeNode(node: TupleTypeNode, elementTypes: ReadonlyArray<TypeNode>): TupleTypeNode;
+    function createOptionalTypeNode(type: TypeNode): OptionalTypeNode;
+    function updateOptionalTypeNode(node: OptionalTypeNode, type: TypeNode): OptionalTypeNode;
+    function createRestTypeNode(type: TypeNode): RestTypeNode;
+    function updateRestTypeNode(node: RestTypeNode, type: TypeNode): RestTypeNode;
     function createUnionTypeNode(types: ReadonlyArray<TypeNode>): UnionTypeNode;
     function updateUnionTypeNode(node: UnionTypeNode, types: NodeArray<TypeNode>): UnionTypeNode;
     function createIntersectionTypeNode(types: ReadonlyArray<TypeNode>): IntersectionTypeNode;

tests/baselines/reference/argumentExpressionContextualTyping.errors.txt

@@ -1,6 +1,8 @@
 tests/cases/conformance/expressions/contextualTyping/argumentExpressionContextualTyping.ts(16,5): error TS2345: Argument of type '(string | number | boolean)[]' is not assignable to parameter of type '[string, number, boolean]'.
   Property '0' is missing in type '(string | number | boolean)[]'.
-tests/cases/conformance/expressions/contextualTyping/argumentExpressionContextualTyping.ts(17,5): error TS2345: Argument of type '(string | number | boolean)[]' is not assignable to parameter of type '[string, number, boolean]'.
+tests/cases/conformance/expressions/contextualTyping/argumentExpressionContextualTyping.ts(17,5): error TS2345: Argument of type '[string, number, true, ...(string | number | boolean)[]]' is not assignable to parameter of type '[string, number, boolean]'.
+  Types of property 'length' are incompatible.
+    Type 'number' is not assignable to type '3'.
 tests/cases/conformance/expressions/contextualTyping/argumentExpressionContextualTyping.ts(18,5): error TS2345: Argument of type '{ x: (string | number)[]; y: { c: boolean; d: string; e: number; }; }' is not assignable to parameter of type '{ x: [any, any]; y: { c: any; d: any; e: any; }; }'.
   Types of property 'x' are incompatible.
     Type '(string | number)[]' is not assignable to type '[any, any]'.
@@ -29,7 +31,9 @@ tests/cases/conformance/expressions/contextualTyping/argumentExpressionContextua
 !!! error TS2345:   Property '0' is missing in type '(string | number | boolean)[]'.
     baz(["string", 1, true, ...array]);  // Error
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '(string | number | boolean)[]' is not assignable to parameter of type '[string, number, boolean]'.
+!!! error TS2345: Argument of type '[string, number, true, ...(string | number | boolean)[]]' is not assignable to parameter of type '[string, number, boolean]'.
+!!! error TS2345:   Types of property 'length' are incompatible.
+!!! error TS2345:     Type 'number' is not assignable to type '3'.
     foo(o);                              // Error because x has an array type namely (string|number)[]
         ~
 !!! error TS2345: Argument of type '{ x: (string | number)[]; y: { c: boolean; d: string; e: number; }; }' is not assignable to parameter of type '{ x: [any, any]; y: { c: any; d: any; e: any; }; }'.

tests/baselines/reference/argumentExpressionContextualTyping.types

@@ -11,7 +11,7 @@ function foo({x: [a, b], y: {c, d, e}}) { }
 >e : any
 
 function bar({x: [a, b = 10], y: {c, d, e = { f:1 }}}) { }
->bar : ({ x: [a, b], y: { c, d, e } }: { x: [any, number]; y: { c: any; d: any; e?: { f: number; }; }; }) => void
+>bar : ({ x: [a, b], y: { c, d, e } }: { x: [any, number?]; y: { c: any; d: any; e?: { f: number; }; }; }) => void
 >x : any
 >a : any
 >b : number

tests/baselines/reference/arrayLiteralExpressionContextualTyping.errors.txt

@@ -7,8 +7,9 @@ tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionConte
 tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(8,5): error TS2322: Type '[number, number, number, string]' is not assignable to type '[number, number, number]'.
   Types of property 'length' are incompatible.
     Type '4' is not assignable to type '3'.
-tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(14,5): error TS2322: Type 'number[]' is not assignable to type '[number, number, number]'.
-  Property '0' is missing in type 'number[]'.
+tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts(14,5): error TS2322: Type '[number, number, number, ...number[]]' is not assignable to type '[number, number, number]'.
+  Types of property 'length' are incompatible.
+    Type 'number' is not assignable to type '3'.
 
 
 ==== tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionContextualTyping.ts (4 errors) ====
@@ -39,6 +40,7 @@ tests/cases/conformance/expressions/contextualTyping/arrayLiteralExpressionConte
     var spr1 = [1, 2, 3, ...tup];
     var spr2:[number, number, number] = [1, 2, 3, ...tup];  // Error
         ~~~~
-!!! error TS2322: Type 'number[]' is not assignable to type '[number, number, number]'.
-!!! error TS2322:   Property '0' is missing in type 'number[]'.
+!!! error TS2322: Type '[number, number, number, ...number[]]' is not assignable to type '[number, number, number]'.
+!!! error TS2322:   Types of property 'length' are incompatible.
+!!! error TS2322:     Type 'number' is not assignable to type '3'.
     

tests/baselines/reference/arrayLiteralExpressionContextualTyping.types

@@ -62,7 +62,7 @@ var spr1 = [1, 2, 3, ...tup];
 
 var spr2:[number, number, number] = [1, 2, 3, ...tup];  // Error
 >spr2 : [number, number, number]
->[1, 2, 3, ...tup] : number[]
+>[1, 2, 3, ...tup] : [number, number, number, ...number[]]
 >1 : 1
 >2 : 2
 >3 : 3

tests/baselines/reference/arrayLiterals3.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(10,5): error TS2322: Type 'undefined[]' is not assignable to type '[any, any, any]'.
-  Property '0' is missing in type 'undefined[]'.
+tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(10,5): error TS2322: Type '[]' is not assignable to type '[any, any, any]'.
+  Property '0' is missing in type '[]'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(11,5): error TS2322: Type '[string, number, boolean]' is not assignable to type '[boolean, string, number]'.
   Type 'string' is not assignable to type 'boolean'.
 tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(17,5): error TS2322: Type '[number, number, string, boolean]' is not assignable to type '[number, number]'.
@@ -30,8 +30,8 @@ tests/cases/conformance/expressions/arrayLiterals/arrayLiterals3.ts(34,5): error
     
     var a0: [any, any, any] = [];                             // Error
         ~~
-!!! error TS2322: Type 'undefined[]' is not assignable to type '[any, any, any]'.
-!!! error TS2322:   Property '0' is missing in type 'undefined[]'.
+!!! error TS2322: Type '[]' is not assignable to type '[any, any, any]'.
+!!! error TS2322:   Property '0' is missing in type '[]'.
     var a1: [boolean, string, number] = ["string", 1, true];  // Error
         ~~
 !!! error TS2322: Type '[string, number, boolean]' is not assignable to type '[boolean, string, number]'.

tests/baselines/reference/arrayLiterals3.types

@@ -10,7 +10,7 @@
 
 var a0: [any, any, any] = [];                             // Error
 >a0 : [any, any, any]
->[] : undefined[]
+>[] : []
 
 var a1: [boolean, string, number] = ["string", 1, true];  // Error
 >a1 : [boolean, string, number]

tests/baselines/reference/arrowFunctionExpressions.types

@@ -71,14 +71,14 @@ var p3 = ([, a]) => { };
 >a : any
 
 var p4 = ([, ...a]) => { };
->p4 : ([, ...a]: any[]) => void
->([, ...a]) => { } : ([, ...a]: any[]) => void
+>p4 : ([, ...a]: [any?, ...any[]]) => void
+>([, ...a]) => { } : ([, ...a]: [any?, ...any[]]) => void
 > : undefined
 >a : any[]
 
 var p5 = ([a = 1]) => { };
->p5 : ([a]: [number]) => void
->([a = 1]) => { } : ([a]: [number]) => void
+>p5 : ([a]: [number?]) => void
+>([a = 1]) => { } : ([a]: [number?]) => void
 >a : number
 >1 : 1
 

tests/baselines/reference/callWithSpread2.errors.txt

@@ -2,19 +2,16 @@ tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(22,1): erro
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(23,1): error TS2556: Expected 0 arguments, but got 1 or more.
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(26,5): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(27,5): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-  Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(27,5): error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(28,13): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(29,13): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-  Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(29,13): error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(30,11): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(31,11): error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-  Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(31,11): error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(32,1): error TS2556: Expected 1-3 arguments, but got 0 or more.
 tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(33,1): error TS2556: Expected 1-3 arguments, but got 0 or more.
-tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(34,1): error TS2556: Expected 1-3 arguments, but got 0 or more.
+tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(34,8): error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'.
 
 
 ==== tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts (11 errors) ====
@@ -53,24 +50,21 @@ tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(34,1): erro
 !!! error TS2345:   Type 'string' is not assignable to type 'number'.
     all(...tuple)
         ~~~~~~~~
-!!! error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-!!! error TS2345:   Type 'string' is not assignable to type 'number'.
+!!! error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
     prefix("b", ...mixed)
                 ~~~~~~~~
 !!! error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
 !!! error TS2345:   Type 'string' is not assignable to type 'number'.
     prefix("c", ...tuple)
                 ~~~~~~~~
-!!! error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-!!! error TS2345:   Type 'string' is not assignable to type 'number'.
+!!! error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
     rest("e", ...mixed)
               ~~~~~~~~
 !!! error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
 !!! error TS2345:   Type 'string' is not assignable to type 'number'.
     rest("f", ...tuple)
               ~~~~~~~~
-!!! error TS2345: Argument of type 'string | number' is not assignable to parameter of type 'number'.
-!!! error TS2345:   Type 'string' is not assignable to type 'number'.
+!!! error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'.
     prefix(...ns) // required parameters are required
     ~~~~~~~~~~~~~
 !!! error TS2556: Expected 1-3 arguments, but got 0 or more.
@@ -78,6 +72,6 @@ tests/cases/conformance/expressions/functionCalls/callWithSpread2.ts(34,1): erro
     ~~~~~~~~~~~~~~~~
 !!! error TS2556: Expected 1-3 arguments, but got 0 or more.
     prefix(...tuple)
-    ~~~~~~~~~~~~~~~~
-!!! error TS2556: Expected 1-3 arguments, but got 0 or more.
+           ~~~~~~~~
+!!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'.
     

tests/baselines/reference/declarationEmitDestructuring3.js

@@ -14,5 +14,5 @@ function foo(_a) {
 
 
 //// [declarationEmitDestructuring3.d.ts]
-declare function bar([x, z, ...w]: any[]): void;
-declare function foo([x, ...y]?: (string | number | boolean)[]): void;
+declare function bar([x, z, ...w]: [any, any, ...any[]]): void;
+declare function foo([x, ...y]?: [number, string, boolean]): void;

tests/baselines/reference/declarationEmitDestructuring3.types

@@ -1,15 +1,15 @@
 === tests/cases/compiler/declarationEmitDestructuring3.ts ===
 function bar([x, z, ...w]) { }
->bar : ([x, z, ...w]: any[]) => void
+>bar : ([x, z, ...w]: [any, any, ...any[]]) => void
 >x : any
 >z : any
 >w : any[]
 
 function foo([x, ...y] = [1, "string", true]) { }
->foo : ([x, ...y]?: (string | number | boolean)[]) => void
->x : string | number | boolean
->y : (string | number | boolean)[]
->[1, "string", true] : (string | number | boolean)[]
+>foo : ([x, ...y]?: [number, string, boolean]) => void
+>x : number
+>y : (string | boolean)[]
+>[1, "string", true] : [number, string, boolean]
 >1 : 1
 >"string" : "string"
 >true : true

tests/baselines/reference/declarationEmitDestructuring5.js

@@ -24,8 +24,8 @@ function bar2(_a) {
 
 
 //// [declarationEmitDestructuring5.d.ts]
-declare function baz([, z, ,]: [any, any, any]): void;
+declare function baz([, z, ,]: [any, any, any?]): void;
 declare function foo([, b,]: [any, any]): void;
-declare function bar([z, , ,]: [any, any, any]): void;
+declare function bar([z, , ,]: [any, any?, any?]): void;
 declare function bar1([z, , ,]?: [number, number, number, number, number]): void;
-declare function bar2([, , z, , ,]: [any, any, any, any, any]): void;
+declare function bar2([, , z, , ,]: [any, any, any, any?, any?]): void;

tests/baselines/reference/declarationEmitDestructuring5.types

@@ -1,6 +1,6 @@
 === tests/cases/compiler/declarationEmitDestructuring5.ts ===
 function baz([, z, , ]) { }
->baz : ([, z, ,]: [any, any, any]) => void
+>baz : ([, z, ,]: [any, any, any?]) => void
 > : undefined
 >z : any
 > : undefined
@@ -11,7 +11,7 @@ function foo([, b, ]: [any, any]): void { }
 >b : any
 
 function bar([z, , , ]) { }
->bar : ([z, , ,]: [any, any, any]) => void
+>bar : ([z, , ,]: [any, any?, any?]) => void
 >z : any
 > : undefined
 > : undefined
@@ -29,7 +29,7 @@ function bar1([z, , , ] = [1, 3, 4, 6, 7]) { }
 >7 : 7
 
 function bar2([,,z, , , ]) { }
->bar2 : ([, , z, , ,]: [any, any, any, any, any]) => void
+>bar2 : ([, , z, , ,]: [any, any, any, any?, any?]) => void
 > : undefined
 > : undefined
 >z : any

tests/baselines/reference/declarationEmitDestructuringArrayPattern2.types

@@ -23,7 +23,7 @@ var [a11, b11, c11] = [];
 >a11 : any
 >b11 : any
 >c11 : any
->[] : [undefined, undefined, undefined]
+>[] : [undefined?, undefined?, undefined?]
 
 var [a2, [b2, { x12, y12: c2 }]=["abc", { x12: 10, y12: false }]] = [1, ["hello", { x12: 5, y12: true }]];
 >a2 : number

tests/baselines/reference/declarationEmitDestructuringArrayPattern4.js

@@ -24,8 +24,8 @@ var _f = [1, "hello", true], x19 = _f[0], y19 = _f[1], z19 = _f[2], a13 = _f.sli
 declare var a5: number[];
 declare var x14: number, a6: number[];
 declare var x15: number, y15: number, a7: number[];
-declare var x16: number, y16: number, z16: number, a8: number[];
+declare var x16: number, y16: number, z16: number, a8: any[];
 declare var a9: (string | number | boolean)[];
-declare var x17: string | number | boolean, a10: (string | number | boolean)[];
-declare var x18: string | number | boolean, y18: string | number | boolean, a12: (string | number | boolean)[];
-declare var x19: string | number | boolean, y19: string | number | boolean, z19: string | number | boolean, a13: (string | number | boolean)[];
+declare var x17: number, a10: (string | boolean)[];
+declare var x18: number, y18: string, a12: boolean[];
+declare var x19: number, y19: string, z19: boolean, a13: any[];

tests/baselines/reference/declarationEmitDestructuringArrayPattern4.types

@@ -9,7 +9,7 @@ var [...a5] = [1, 2, 3];
 var [x14, ...a6] = [1, 2, 3];
 >x14 : number
 >a6 : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -18,7 +18,7 @@ var [x15, y15, ...a7] = [1, 2, 3];
 >x15 : number
 >y15 : number
 >a7 : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -27,8 +27,8 @@ var [x16, y16, z16, ...a8] = [1, 2, 3];
 >x16 : number
 >y16 : number
 >z16 : number
->a8 : number[]
->[1, 2, 3] : number[]
+>a8 : any[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -41,28 +41,28 @@ var [...a9] = [1, "hello", true];
 >true : true
 
 var [x17, ...a10] = [1, "hello", true];
->x17 : string | number | boolean
->a10 : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+>x17 : number
+>a10 : (string | boolean)[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
 var [x18, y18, ...a12] = [1, "hello", true];
->x18 : string | number | boolean
->y18 : string | number | boolean
->a12 : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+>x18 : number
+>y18 : string
+>a12 : boolean[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
 var [x19, y19, z19, ...a13] = [1, "hello", true];
->x19 : string | number | boolean
->y19 : string | number | boolean
->z19 : string | number | boolean
->a13 : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+>x19 : number
+>y19 : string
+>z19 : boolean
+>a13 : any[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true

tests/baselines/reference/declarationsAndAssignments.errors.txt

@@ -103,7 +103,7 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(138,9):
     }
     
     function f8() {
-        var [a, b, c] = [];   // Ok, [] is an array
+        var [a, b, c] = [];   // Error, [] is an empty tuple
              ~
 !!! error TS2525: Initializer provides no value for this binding element and the binding element has no default value.
                 ~
@@ -224,32 +224,36 @@ tests/cases/conformance/es6/destructuring/declarationsAndAssignments.ts(138,9):
     }
     
     function f20() {
-        var a: number[];
         var x: number;
         var y: number;
         var z: number;
+        var a: number[];
+        var a3: any[];
         var [...a] = [1, 2, 3];
         var [x, ...a] = [1, 2, 3];
         var [x, y, ...a] = [1, 2, 3];
-        var [x, y, z, ...a] = [1, 2, 3];
+        var [x, y, z, ...a3] = [1, 2, 3];
         [...a] = [1, 2, 3];
         [x, ...a] = [1, 2, 3];
         [x, y, ...a] = [1, 2, 3];
-        [x, y, z, ...a] = [1, 2, 3];
+        [x, y, z, ...a3] = [1, 2, 3];
     }
     
     function f21() {
-        var a: (number | string | boolean)[];
-        var x: number | string | boolean;
-        var y: number | string | boolean;
-        var z: number | string | boolean;
-        var [...a] = [1, "hello", true];
-        var [x, ...a] = [1, "hello", true];
-        var [x, y, ...a] = [1, "hello", true];
-        var [x, y, z, ...a] = [1, "hello", true];
-        [...a] = [1, "hello", true];
-        [x, ...a] = [1, "hello", true];
-        [x, y, ...a] = [1, "hello", true];
-        [x, y, z, ...a] = [1, "hello", true];
+        var x: number;
+        var y: string;
+        var z: boolean;
+        var a0: (number | string | boolean)[];
+        var a1: (string | boolean)[];
+        var a2: boolean[];
+        var a3: any[];
+        var [...a0] = [1, "hello", true];
+        var [x, ...a1] = [1, "hello", true];
+        var [x, y, ...a2] = [1, "hello", true];
+        var [x, y, z, ...a3] = [1, "hello", true];
+        [...a0] = [1, "hello", true];
+        [x, ...a1] = [1, "hello", true];
+        [x, y, ...a2] = [1, "hello", true];
+        [x, y, z, ...a3] = [1, "hello", true];
     }
     

tests/baselines/reference/declarationsAndAssignments.js

@@ -60,7 +60,7 @@ function f7() {
 }
 
 function f8() {
-    var [a, b, c] = [];   // Ok, [] is an array
+    var [a, b, c] = [];   // Error, [] is an empty tuple
     var [d, e, f] = [1];  // Error, [1] is a tuple
 }
 
@@ -150,33 +150,37 @@ function f19() {
 }
 
 function f20() {
-    var a: number[];
     var x: number;
     var y: number;
     var z: number;
+    var a: number[];
+    var a3: any[];
     var [...a] = [1, 2, 3];
     var [x, ...a] = [1, 2, 3];
     var [x, y, ...a] = [1, 2, 3];
-    var [x, y, z, ...a] = [1, 2, 3];
+    var [x, y, z, ...a3] = [1, 2, 3];
     [...a] = [1, 2, 3];
     [x, ...a] = [1, 2, 3];
     [x, y, ...a] = [1, 2, 3];
-    [x, y, z, ...a] = [1, 2, 3];
+    [x, y, z, ...a3] = [1, 2, 3];
 }
 
 function f21() {
-    var a: (number | string | boolean)[];
-    var x: number | string | boolean;
-    var y: number | string | boolean;
-    var z: number | string | boolean;
-    var [...a] = [1, "hello", true];
-    var [x, ...a] = [1, "hello", true];
-    var [x, y, ...a] = [1, "hello", true];
-    var [x, y, z, ...a] = [1, "hello", true];
-    [...a] = [1, "hello", true];
-    [x, ...a] = [1, "hello", true];
-    [x, y, ...a] = [1, "hello", true];
-    [x, y, z, ...a] = [1, "hello", true];
+    var x: number;
+    var y: string;
+    var z: boolean;
+    var a0: (number | string | boolean)[];
+    var a1: (string | boolean)[];
+    var a2: boolean[];
+    var a3: any[];
+    var [...a0] = [1, "hello", true];
+    var [x, ...a1] = [1, "hello", true];
+    var [x, y, ...a2] = [1, "hello", true];
+    var [x, y, z, ...a3] = [1, "hello", true];
+    [...a0] = [1, "hello", true];
+    [x, ...a1] = [1, "hello", true];
+    [x, y, ...a2] = [1, "hello", true];
+    [x, y, z, ...a3] = [1, "hello", true];
 }
 
 
@@ -235,7 +239,7 @@ function f7() {
     var y;
 }
 function f8() {
-    var _a = [], a = _a[0], b = _a[1], c = _a[2]; // Ok, [] is an array
+    var _a = [], a = _a[0], b = _a[1], c = _a[2]; // Error, [] is an empty tuple
     var _b = [1], d = _b[0], e = _b[1], f = _b[2]; // Error, [1] is a tuple
 }
 function f9() {
@@ -318,31 +322,35 @@ function f19() {
 }
 function f20() {
     var _a, _b, _c;
-    var a;
     var x;
     var y;
     var z;
+    var a;
+    var a3;
     var a = [1, 2, 3].slice(0);
     var _d = [1, 2, 3], x = _d[0], a = _d.slice(1);
     var _e = [1, 2, 3], x = _e[0], y = _e[1], a = _e.slice(2);
-    var _f = [1, 2, 3], x = _f[0], y = _f[1], z = _f[2], a = _f.slice(3);
+    var _f = [1, 2, 3], x = _f[0], y = _f[1], z = _f[2], a3 = _f.slice(3);
     a = [1, 2, 3].slice(0);
     _a = [1, 2, 3], x = _a[0], a = _a.slice(1);
     _b = [1, 2, 3], x = _b[0], y = _b[1], a = _b.slice(2);
-    _c = [1, 2, 3], x = _c[0], y = _c[1], z = _c[2], a = _c.slice(3);
+    _c = [1, 2, 3], x = _c[0], y = _c[1], z = _c[2], a3 = _c.slice(3);
 }
 function f21() {
     var _a, _b, _c;
-    var a;
     var x;
     var y;
     var z;
-    var a = [1, "hello", true].slice(0);
-    var _d = [1, "hello", true], x = _d[0], a = _d.slice(1);
-    var _e = [1, "hello", true], x = _e[0], y = _e[1], a = _e.slice(2);
-    var _f = [1, "hello", true], x = _f[0], y = _f[1], z = _f[2], a = _f.slice(3);
-    a = [1, "hello", true].slice(0);
-    _a = [1, "hello", true], x = _a[0], a = _a.slice(1);
-    _b = [1, "hello", true], x = _b[0], y = _b[1], a = _b.slice(2);
-    _c = [1, "hello", true], x = _c[0], y = _c[1], z = _c[2], a = _c.slice(3);
+    var a0;
+    var a1;
+    var a2;
+    var a3;
+    var a0 = [1, "hello", true].slice(0);
+    var _d = [1, "hello", true], x = _d[0], a1 = _d.slice(1);
+    var _e = [1, "hello", true], x = _e[0], y = _e[1], a2 = _e.slice(2);
+    var _f = [1, "hello", true], x = _f[0], y = _f[1], z = _f[2], a3 = _f.slice(3);
+    a0 = [1, "hello", true].slice(0);
+    _a = [1, "hello", true], x = _a[0], a1 = _a.slice(1);
+    _b = [1, "hello", true], x = _b[0], y = _b[1], a2 = _b.slice(2);
+    _c = [1, "hello", true], x = _c[0], y = _c[1], z = _c[2], a3 = _c.slice(3);
 }

tests/baselines/reference/declarationsAndAssignments.symbols

@@ -189,7 +189,7 @@ function f7() {
 function f8() {
 >f8 : Symbol(f8, Decl(declarationsAndAssignments.ts, 58, 1))
 
-    var [a, b, c] = [];   // Ok, [] is an array
+    var [a, b, c] = [];   // Error, [] is an empty tuple
 >a : Symbol(a, Decl(declarationsAndAssignments.ts, 61, 9))
 >b : Symbol(b, Decl(declarationsAndAssignments.ts, 61, 11))
 >c : Symbol(c, Decl(declarationsAndAssignments.ts, 61, 14))
@@ -474,104 +474,116 @@ function f19() {
 function f20() {
 >f20 : Symbol(f20, Decl(declarationsAndAssignments.ts, 148, 1))
 
-    var a: number[];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
-
     var x: number;
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
 
     var y: number;
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 11))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 158, 11), Decl(declarationsAndAssignments.ts, 159, 11))
 
     var z: number;
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 158, 14))
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 159, 14))
+
+    var a: number[];
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
+
+    var a3: any[];
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 155, 7), Decl(declarationsAndAssignments.ts, 159, 17))
 
     var [...a] = [1, 2, 3];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
     var [x, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
     var [x, y, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 11))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 158, 11), Decl(declarationsAndAssignments.ts, 159, 11))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
-    var [x, y, z, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 11))
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 158, 14))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+    var [x, y, z, ...a3] = [1, 2, 3];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 158, 11), Decl(declarationsAndAssignments.ts, 159, 11))
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 159, 14))
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 155, 7), Decl(declarationsAndAssignments.ts, 159, 17))
 
     [...a] = [1, 2, 3];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
     [x, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
     [x, y, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 11))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 158, 11), Decl(declarationsAndAssignments.ts, 159, 11))
+>a : Symbol(a, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 14))
 
-    [x, y, z, ...a] = [1, 2, 3];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 156, 9), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 157, 11), Decl(declarationsAndAssignments.ts, 158, 11))
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 154, 7), Decl(declarationsAndAssignments.ts, 158, 14))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 155, 9), Decl(declarationsAndAssignments.ts, 156, 11), Decl(declarationsAndAssignments.ts, 157, 14), Decl(declarationsAndAssignments.ts, 158, 17))
+    [x, y, z, ...a3] = [1, 2, 3];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 151, 7), Decl(declarationsAndAssignments.ts, 157, 9), Decl(declarationsAndAssignments.ts, 158, 9), Decl(declarationsAndAssignments.ts, 159, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 152, 7), Decl(declarationsAndAssignments.ts, 158, 11), Decl(declarationsAndAssignments.ts, 159, 11))
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 153, 7), Decl(declarationsAndAssignments.ts, 159, 14))
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 155, 7), Decl(declarationsAndAssignments.ts, 159, 17))
 }
 
 function f21() {
->f21 : Symbol(f21, Decl(declarationsAndAssignments.ts, 163, 1))
+>f21 : Symbol(f21, Decl(declarationsAndAssignments.ts, 164, 1))
 
-    var a: (number | string | boolean)[];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var x: number;
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
 
-    var x: number | string | boolean;
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
+    var y: string;
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 176, 11), Decl(declarationsAndAssignments.ts, 177, 11))
 
-    var y: number | string | boolean;
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 172, 11), Decl(declarationsAndAssignments.ts, 173, 11))
+    var z: boolean;
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 177, 14))
 
-    var z: number | string | boolean;
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 173, 14))
+    var a0: (number | string | boolean)[];
+>a0 : Symbol(a0, Decl(declarationsAndAssignments.ts, 170, 7), Decl(declarationsAndAssignments.ts, 174, 9))
 
-    var [...a] = [1, "hello", true];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var a1: (string | boolean)[];
+>a1 : Symbol(a1, Decl(declarationsAndAssignments.ts, 171, 7), Decl(declarationsAndAssignments.ts, 175, 11))
 
-    var [x, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var a2: boolean[];
+>a2 : Symbol(a2, Decl(declarationsAndAssignments.ts, 172, 7), Decl(declarationsAndAssignments.ts, 176, 14))
 
-    var [x, y, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 172, 11), Decl(declarationsAndAssignments.ts, 173, 11))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var a3: any[];
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 173, 7), Decl(declarationsAndAssignments.ts, 177, 17))
 
-    var [x, y, z, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 172, 11), Decl(declarationsAndAssignments.ts, 173, 11))
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 173, 14))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var [...a0] = [1, "hello", true];
+>a0 : Symbol(a0, Decl(declarationsAndAssignments.ts, 170, 7), Decl(declarationsAndAssignments.ts, 174, 9))
 
-    [...a] = [1, "hello", true];
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var [x, ...a1] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>a1 : Symbol(a1, Decl(declarationsAndAssignments.ts, 171, 7), Decl(declarationsAndAssignments.ts, 175, 11))
 
-    [x, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var [x, y, ...a2] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 176, 11), Decl(declarationsAndAssignments.ts, 177, 11))
+>a2 : Symbol(a2, Decl(declarationsAndAssignments.ts, 172, 7), Decl(declarationsAndAssignments.ts, 176, 14))
 
-    [x, y, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 172, 11), Decl(declarationsAndAssignments.ts, 173, 11))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    var [x, y, z, ...a3] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 176, 11), Decl(declarationsAndAssignments.ts, 177, 11))
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 177, 14))
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 173, 7), Decl(declarationsAndAssignments.ts, 177, 17))
 
-    [x, y, z, ...a] = [1, "hello", true];
->x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 171, 9), Decl(declarationsAndAssignments.ts, 172, 9), Decl(declarationsAndAssignments.ts, 173, 9))
->y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 172, 11), Decl(declarationsAndAssignments.ts, 173, 11))
->z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 173, 14))
->a : Symbol(a, Decl(declarationsAndAssignments.ts, 166, 7), Decl(declarationsAndAssignments.ts, 170, 9), Decl(declarationsAndAssignments.ts, 171, 11), Decl(declarationsAndAssignments.ts, 172, 14), Decl(declarationsAndAssignments.ts, 173, 17))
+    [...a0] = [1, "hello", true];
+>a0 : Symbol(a0, Decl(declarationsAndAssignments.ts, 170, 7), Decl(declarationsAndAssignments.ts, 174, 9))
+
+    [x, ...a1] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>a1 : Symbol(a1, Decl(declarationsAndAssignments.ts, 171, 7), Decl(declarationsAndAssignments.ts, 175, 11))
+
+    [x, y, ...a2] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 176, 11), Decl(declarationsAndAssignments.ts, 177, 11))
+>a2 : Symbol(a2, Decl(declarationsAndAssignments.ts, 172, 7), Decl(declarationsAndAssignments.ts, 176, 14))
+
+    [x, y, z, ...a3] = [1, "hello", true];
+>x : Symbol(x, Decl(declarationsAndAssignments.ts, 167, 7), Decl(declarationsAndAssignments.ts, 175, 9), Decl(declarationsAndAssignments.ts, 176, 9), Decl(declarationsAndAssignments.ts, 177, 9))
+>y : Symbol(y, Decl(declarationsAndAssignments.ts, 168, 7), Decl(declarationsAndAssignments.ts, 176, 11), Decl(declarationsAndAssignments.ts, 177, 11))
+>z : Symbol(z, Decl(declarationsAndAssignments.ts, 169, 7), Decl(declarationsAndAssignments.ts, 177, 14))
+>a3 : Symbol(a3, Decl(declarationsAndAssignments.ts, 173, 7), Decl(declarationsAndAssignments.ts, 177, 17))
 }
 

tests/baselines/reference/declarationsAndAssignments.types

@@ -24,7 +24,7 @@ function f0() {
 >x : number
 >y : string
 >z : any
->[1, "hello"] : [number, string, undefined]
+>[1, "hello"] : [number, string, undefined?]
 >1 : 1
 >"hello" : "hello"
 
@@ -254,17 +254,17 @@ function f7() {
 function f8() {
 >f8 : () => void
 
-    var [a, b, c] = [];   // Ok, [] is an array
+    var [a, b, c] = [];   // Error, [] is an empty tuple
 >a : any
 >b : any
 >c : any
->[] : [undefined, undefined, undefined]
+>[] : [undefined?, undefined?, undefined?]
 
     var [d, e, f] = [1];  // Error, [1] is a tuple
 >d : number
 >e : any
 >f : any
->[1] : [number, undefined, undefined]
+>[1] : [number, undefined?, undefined?]
 >1 : 1
 }
 
@@ -681,9 +681,6 @@ function f19() {
 function f20() {
 >f20 : () => void
 
-    var a: number[];
->a : number[]
-
     var x: number;
 >x : number
 
@@ -693,6 +690,12 @@ function f20() {
     var z: number;
 >z : number
 
+    var a: number[];
+>a : number[]
+
+    var a3: any[];
+>a3 : any[]
+
     var [...a] = [1, 2, 3];
 >a : number[]
 >[1, 2, 3] : number[]
@@ -703,7 +706,7 @@ function f20() {
     var [x, ...a] = [1, 2, 3];
 >x : number
 >a : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -712,17 +715,17 @@ function f20() {
 >x : number
 >y : number
 >a : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
 
-    var [x, y, z, ...a] = [1, 2, 3];
+    var [x, y, z, ...a3] = [1, 2, 3];
 >x : number
 >y : number
 >z : number
->a : number[]
->[1, 2, 3] : number[]
+>a3 : any[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -738,37 +741,37 @@ function f20() {
 >3 : 3
 
     [x, ...a] = [1, 2, 3];
->[x, ...a] = [1, 2, 3] : number[]
->[x, ...a] : number[]
+>[x, ...a] = [1, 2, 3] : [number, number, number]
+>[x, ...a] : [number, ...number[]]
 >x : number
 >...a : number
 >a : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
 
     [x, y, ...a] = [1, 2, 3];
->[x, y, ...a] = [1, 2, 3] : number[]
->[x, y, ...a] : number[]
+>[x, y, ...a] = [1, 2, 3] : [number, number, number]
+>[x, y, ...a] : [number, number, ...number[]]
 >x : number
 >y : number
 >...a : number
 >a : number[]
->[1, 2, 3] : number[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
 
-    [x, y, z, ...a] = [1, 2, 3];
->[x, y, z, ...a] = [1, 2, 3] : number[]
->[x, y, z, ...a] : number[]
+    [x, y, z, ...a3] = [1, 2, 3];
+>[x, y, z, ...a3] = [1, 2, 3] : [number, number, number]
+>[x, y, z, ...a3] : [number, number, number, ...any[]]
 >x : number
 >y : number
 >z : number
->...a : number
->a : number[]
->[1, 2, 3] : number[]
+>...a3 : any
+>a3 : any[]
+>[1, 2, 3] : [number, number, number]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -777,94 +780,103 @@ function f20() {
 function f21() {
 >f21 : () => void
 
-    var a: (number | string | boolean)[];
->a : (string | number | boolean)[]
+    var x: number;
+>x : number
 
-    var x: number | string | boolean;
->x : string | number | boolean
+    var y: string;
+>y : string
 
-    var y: number | string | boolean;
->y : string | number | boolean
+    var z: boolean;
+>z : boolean
 
-    var z: number | string | boolean;
->z : string | number | boolean
+    var a0: (number | string | boolean)[];
+>a0 : (string | number | boolean)[]
 
-    var [...a] = [1, "hello", true];
->a : (string | number | boolean)[]
+    var a1: (string | boolean)[];
+>a1 : (string | boolean)[]
+
+    var a2: boolean[];
+>a2 : boolean[]
+
+    var a3: any[];
+>a3 : any[]
+
+    var [...a0] = [1, "hello", true];
+>a0 : (string | number | boolean)[]
 >[1, "hello", true] : (string | number | boolean)[]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    var [x, ...a] = [1, "hello", true];
->x : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+    var [x, ...a1] = [1, "hello", true];
+>x : number
+>a1 : (string | boolean)[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    var [x, y, ...a] = [1, "hello", true];
->x : string | number | boolean
->y : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+    var [x, y, ...a2] = [1, "hello", true];
+>x : number
+>y : string
+>a2 : boolean[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    var [x, y, z, ...a] = [1, "hello", true];
->x : string | number | boolean
->y : string | number | boolean
->z : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | boolean)[]
+    var [x, y, z, ...a3] = [1, "hello", true];
+>x : number
+>y : string
+>z : boolean
+>a3 : any[]
+>[1, "hello", true] : [number, string, boolean]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    [...a] = [1, "hello", true];
->[...a] = [1, "hello", true] : (string | number | true)[]
->[...a] : (string | number | boolean)[]
->...a : string | number | boolean
->a : (string | number | boolean)[]
+    [...a0] = [1, "hello", true];
+>[...a0] = [1, "hello", true] : (string | number | true)[]
+>[...a0] : (string | number | boolean)[]
+>...a0 : string | number | boolean
+>a0 : (string | number | boolean)[]
 >[1, "hello", true] : (string | number | true)[]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    [x, ...a] = [1, "hello", true];
->[x, ...a] = [1, "hello", true] : (string | number | true)[]
->[x, ...a] : (string | number | boolean)[]
->x : string | number | boolean
->...a : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | true)[]
+    [x, ...a1] = [1, "hello", true];
+>[x, ...a1] = [1, "hello", true] : [number, string, true]
+>[x, ...a1] : [number, ...(string | boolean)[]]
+>x : number
+>...a1 : string | boolean
+>a1 : (string | boolean)[]
+>[1, "hello", true] : [number, string, true]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    [x, y, ...a] = [1, "hello", true];
->[x, y, ...a] = [1, "hello", true] : (string | number | true)[]
->[x, y, ...a] : (string | number | boolean)[]
->x : string | number | boolean
->y : string | number | boolean
->...a : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | true)[]
+    [x, y, ...a2] = [1, "hello", true];
+>[x, y, ...a2] = [1, "hello", true] : [number, string, true]
+>[x, y, ...a2] : [number, string, ...boolean[]]
+>x : number
+>y : string
+>...a2 : boolean
+>a2 : boolean[]
+>[1, "hello", true] : [number, string, true]
 >1 : 1
 >"hello" : "hello"
 >true : true
 
-    [x, y, z, ...a] = [1, "hello", true];
->[x, y, z, ...a] = [1, "hello", true] : (string | number | true)[]
->[x, y, z, ...a] : (string | number | boolean)[]
->x : string | number | boolean
->y : string | number | boolean
->z : string | number | boolean
->...a : string | number | boolean
->a : (string | number | boolean)[]
->[1, "hello", true] : (string | number | true)[]
+    [x, y, z, ...a3] = [1, "hello", true];
+>[x, y, z, ...a3] = [1, "hello", true] : [number, string, true]
+>[x, y, z, ...a3] : [number, string, boolean, ...any[]]
+>x : number
+>y : string
+>z : boolean
+>...a3 : any
+>a3 : any[]
+>[1, "hello", true] : [number, string, true]
 >1 : 1
 >"hello" : "hello"
 >true : true

tests/baselines/reference/destructuringArrayBindingPatternAndAssignment1ES5.types

@@ -93,18 +93,18 @@ var [c0, c1] = [...temp];
 
 var [c2] = [];
 >c2 : any
->[] : [undefined]
+>[] : [undefined?]
 
 var [[[c3]], [[[[c4]]]]] = [[[]], [[[[]]]]]
 >c3 : any
 >c4 : any
->[[[]], [[[[]]]]] : [[[undefined]], [[[[undefined]]]]]
->[[]] : [[undefined]]
->[] : [undefined]
->[[[[]]]] : [[[[undefined]]]]
->[[[]]] : [[[undefined]]]
->[[]] : [[undefined]]
->[] : [undefined]
+>[[[]], [[[[]]]]] : [[[undefined?]], [[[[undefined?]]]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
+>[[[[]]]] : [[[[undefined?]]]]
+>[[[]]] : [[[undefined?]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
 
 var [[c5], c6]: [[string|number], boolean] = [[1], true];
 >c5 : string | number
@@ -149,7 +149,7 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 > : undefined
 > : undefined
 >c10 : (string | number)[]
->[1, 2, 3, 4, "hello"] : (string | number)[]
+>[1, 2, 3, 4, "hello"] : [number, number, number, number, string]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -157,10 +157,10 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 >"hello" : "hello"
 
 var [c11, c12, ...c13] = [1, 2, "string"];
->c11 : string | number
->c12 : string | number
->c13 : (string | number)[]
->[1, 2, "string"] : (string | number)[]
+>c11 : number
+>c12 : number
+>c13 : string[]
+>[1, 2, "string"] : [number, number, string]
 >1 : 1
 >2 : 2
 >"string" : "string"

tests/baselines/reference/destructuringArrayBindingPatternAndAssignment1ES5iterable.types

@@ -93,18 +93,18 @@ var [c0, c1] = [...temp];
 
 var [c2] = [];
 >c2 : any
->[] : [undefined]
+>[] : [undefined?]
 
 var [[[c3]], [[[[c4]]]]] = [[[]], [[[[]]]]]
 >c3 : any
 >c4 : any
->[[[]], [[[[]]]]] : [[[undefined]], [[[[undefined]]]]]
->[[]] : [[undefined]]
->[] : [undefined]
->[[[[]]]] : [[[[undefined]]]]
->[[[]]] : [[[undefined]]]
->[[]] : [[undefined]]
->[] : [undefined]
+>[[[]], [[[[]]]]] : [[[undefined?]], [[[[undefined?]]]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
+>[[[[]]]] : [[[[undefined?]]]]
+>[[[]]] : [[[undefined?]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
 
 var [[c5], c6]: [[string|number], boolean] = [[1], true];
 >c5 : string | number
@@ -149,7 +149,7 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 > : undefined
 > : undefined
 >c10 : (string | number)[]
->[1, 2, 3, 4, "hello"] : (string | number)[]
+>[1, 2, 3, 4, "hello"] : [number, number, number, number, string]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -157,10 +157,10 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 >"hello" : "hello"
 
 var [c11, c12, ...c13] = [1, 2, "string"];
->c11 : string | number
->c12 : string | number
->c13 : (string | number)[]
->[1, 2, "string"] : (string | number)[]
+>c11 : number
+>c12 : number
+>c13 : string[]
+>[1, 2, "string"] : [number, number, string]
 >1 : 1
 >2 : 2
 >"string" : "string"

tests/baselines/reference/destructuringArrayBindingPatternAndAssignment1ES6.types

@@ -93,18 +93,18 @@ var [c0, c1] = [...temp];
 
 var [c2] = [];
 >c2 : any
->[] : [undefined]
+>[] : [undefined?]
 
 var [[[c3]], [[[[c4]]]]] = [[[]], [[[[]]]]]
 >c3 : any
 >c4 : any
->[[[]], [[[[]]]]] : [[[undefined]], [[[[undefined]]]]]
->[[]] : [[undefined]]
->[] : [undefined]
->[[[[]]]] : [[[[undefined]]]]
->[[[]]] : [[[undefined]]]
->[[]] : [[undefined]]
->[] : [undefined]
+>[[[]], [[[[]]]]] : [[[undefined?]], [[[[undefined?]]]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
+>[[[[]]]] : [[[[undefined?]]]]
+>[[[]]] : [[[undefined?]]]
+>[[]] : [[undefined?]]
+>[] : [undefined?]
 
 var [[c5], c6]: [[string|number], boolean] = [[1], true];
 >c5 : string | number
@@ -149,7 +149,7 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 > : undefined
 > : undefined
 >c10 : (string | number)[]
->[1, 2, 3, 4, "hello"] : (string | number)[]
+>[1, 2, 3, 4, "hello"] : [number, number, number, number, string]
 >1 : 1
 >2 : 2
 >3 : 3
@@ -157,10 +157,10 @@ var [,,,...c10] = [1, 2, 3, 4, "hello"];
 >"hello" : "hello"
 
 var [c11, c12, ...c13] = [1, 2, "string"];
->c11 : string | number
->c12 : string | number
->c13 : (string | number)[]
->[1, 2, "string"] : (string | number)[]
+>c11 : number
+>c12 : number
+>c13 : string[]
+>[1, 2, "string"] : [number, number, string]
 >1 : 1
 >2 : 2
 >"string" : "string"

tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.types

@@ -4,7 +4,7 @@
 var [[a0], [[a1]]] = []         // Error
 >a0 : any
 >a1 : any
->[] : [undefined, undefined]
+>[] : [undefined?, undefined?]
 
 var [[a2], [[a3]]] = undefined  // Error
 >a2 : any

tests/baselines/reference/destructuringArrayBindingPatternAndAssignment3.types

@@ -3,7 +3,7 @@ const [a, b = a] = [1]; // ok
 >a : any
 >b : any
 >a : any
->[1] : [number, any]
+>[1] : [number, any?]
 >1 : 1
 
 const [c, d = c, e = e] = [1]; // error for e = e
@@ -12,7 +12,7 @@ const [c, d = c, e = e] = [1]; // error for e = e
 >c : any
 >e : any
 >e : any
->[1] : [number, any, any]
+>[1] : [number, any?, any?]
 >1 : 1
 
 const [f, g = f, h = i, i = f] = [1]; // error for h = i
@@ -23,7 +23,7 @@ const [f, g = f, h = i, i = f] = [1]; // error for h = i
 >i : any
 >i : any
 >f : any
->[1] : [number, any, any, any]
+>[1] : [number, any?, any?, any?]
 >1 : 1
 
 (function ([a, b = a]) { // ok

tests/baselines/reference/destructuringParameterDeclaration1ES5.types

@@ -229,7 +229,7 @@ function c5([a, b, [[c]]]) { }
 >c : any
 
 function c6([a, b, [[c=1]]]) { }
->c6 : ([a, b, [[c]]]: [any, any, [[number]]]) => void
+>c6 : ([a, b, [[c]]]: [any, any, [[number?]]]) => void
 >a : any
 >b : any
 >c : number

tests/baselines/reference/destructuringParameterDeclaration1ES5iterable.types

@@ -229,7 +229,7 @@ function c5([a, b, [[c]]]) { }
 >c : any
 
 function c6([a, b, [[c=1]]]) { }
->c6 : ([a, b, [[c]]]: [any, any, [[number]]]) => void
+>c6 : ([a, b, [[c]]]: [any, any, [[number?]]]) => void
 >a : any
 >b : any
 >c : number

tests/baselines/reference/destructuringParameterDeclaration1ES6.types

@@ -212,7 +212,7 @@ function c5([a, b, [[c]]]) { }
 >c : any
 
 function c6([a, b, [[c=1]]]) { }
->c6 : ([a, b, [[c]]]: [any, any, [[number]]]) => void
+>c6 : ([a, b, [[c]]]: [any, any, [[number?]]]) => void
 >a : any
 >b : any
 >c : number

tests/baselines/reference/destructuringParameterDeclaration2.errors.txt

@@ -28,10 +28,11 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(39,4): error TS2345: Argument of type '[number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
   Types of property '2' are incompatible.
     Type 'boolean' is not assignable to type '[[any]]'.
-tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(40,4): error TS2345: Argument of type '[number, number, [[string]]]' is not assignable to parameter of type '[any, any, [[number]]]'.
-  Type '[[string]]' is not assignable to type '[[number]]'.
-    Type '[string]' is not assignable to type '[number]'.
-      Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(40,4): error TS2345: Argument of type '[number, number, [[string]]]' is not assignable to parameter of type '[any, any, [[number?]]]'.
+  Type '[[string]]' is not assignable to type '[[number?]]'.
+    Type '[string]' is not assignable to type '[number?]'.
+      Types of property '0' are incompatible.
+        Type 'string' is not assignable to type 'number'.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(46,13): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(47,13): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(56,8): error TS2463: A binding pattern parameter cannot be optional in an implementation signature.
@@ -131,10 +132,11 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration2.ts(
 !!! error TS2345:     Type 'boolean' is not assignable to type '[[any]]'.
     c6([1, 2, [["string"]]]);  // Error, implied type is [any, any, [[number]]]  // Use initializer
        ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type '[number, number, [[string]]]' is not assignable to parameter of type '[any, any, [[number]]]'.
-!!! error TS2345:   Type '[[string]]' is not assignable to type '[[number]]'.
-!!! error TS2345:     Type '[string]' is not assignable to type '[number]'.
-!!! error TS2345:       Type 'string' is not assignable to type 'number'.
+!!! error TS2345: Argument of type '[number, number, [[string]]]' is not assignable to parameter of type '[any, any, [[number?]]]'.
+!!! error TS2345:   Type '[[string]]' is not assignable to type '[[number?]]'.
+!!! error TS2345:     Type '[string]' is not assignable to type '[number?]'.
+!!! error TS2345:       Types of property '0' are incompatible.
+!!! error TS2345:         Type 'string' is not assignable to type 'number'.
     
     // A parameter can be marked optional by following its name or binding pattern with a question mark (?)
     // or by including an initializer.  Initializers (including binding property or element initializers) are

tests/baselines/reference/destructuringParameterDeclaration2.types

@@ -143,7 +143,7 @@ function c5([a, b, [[c]]]) { }
 >c : any
 
 function c6([a, b, [[c = 1]]]) { }
->c6 : ([a, b, [[c]]]: [any, any, [[number]]]) => void
+>c6 : ([a, b, [[c]]]: [any, any, [[number?]]]) => void
 >a : any
 >b : any
 >c : number
@@ -193,7 +193,7 @@ c5([1, 2, false, true]);   // Error, implied type is [any, any, [[any]]]
 
 c6([1, 2, [["string"]]]);  // Error, implied type is [any, any, [[number]]]  // Use initializer
 >c6([1, 2, [["string"]]]) : void
->c6 : ([a, b, [[c]]]: [any, any, [[number]]]) => void
+>c6 : ([a, b, [[c]]]: [any, any, [[number?]]]) => void
 >[1, 2, [["string"]]] : (number | string[][])[]
 >1 : 1
 >2 : 2

tests/baselines/reference/destructuringParameterDeclaration3ES5.errors.txt

@@ -1,9 +1,14 @@
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
   Types of property 'length' are incompatible.
     Type '5' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts(29,5): error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Types of property '2' are incompatible.
+    Type 'number' is not assignable to type '[[any]]'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts(30,5): error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Property '2' is missing in type '[number, number]'.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts (1 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.ts (3 errors) ====
     // If the parameter is a rest parameter, the parameter type is any[]
     // A type annotation for a rest parameter must denote an array type.
     
@@ -37,7 +42,14 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5.
     
     a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
     a10([1, 2, 3, false, true]);              // Parameter type is any[]
+        ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Types of property '2' are incompatible.
+!!! error TS2345:     Type 'number' is not assignable to type '[[any]]'.
     a10([1, 2]);                              // Parameter type is any[]
+        ~~~~~~
+!!! error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Property '2' is missing in type '[number, number]'.
     a11([1, 2]);                              // Parameter type is number[]
     
     // Rest parameter with generic

tests/baselines/reference/destructuringParameterDeclaration3ES5.types

@@ -52,7 +52,7 @@ function a9([a, b, [[c]]]) { }
 >c : any
 
 function a10([a, b, [[c]], ...x]) { }
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >a : any
 >b : any
 >c : any
@@ -107,19 +107,19 @@ a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]
 
 a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
 >a10([1, 2, [["string"]], false, true]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
->[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
+>[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
 >1 : 1
 >2 : 2
->[["string"]] : string[][]
->["string"] : string[]
+>[["string"]] : [[string]]
+>["string"] : [string]
 >"string" : "string"
 >false : false
 >true : true
 
 a10([1, 2, 3, false, true]);              // Parameter type is any[]
 >a10([1, 2, 3, false, true]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2, 3, false, true] : (number | boolean)[]
 >1 : 1
 >2 : 2
@@ -129,7 +129,7 @@ a10([1, 2, 3, false, true]);              // Parameter type is any[]
 
 a10([1, 2]);                              // Parameter type is any[]
 >a10([1, 2]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2] : number[]
 >1 : 1
 >2 : 2

tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.errors.txt

@@ -1,9 +1,14 @@
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
   Types of property 'length' are incompatible.
     Type '5' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts(29,5): error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Types of property '2' are incompatible.
+    Type 'number' is not assignable to type '[[any]]'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts(30,5): error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Property '2' is missing in type '[number, number]'.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts (1 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5iterable.ts (3 errors) ====
     // If the parameter is a rest parameter, the parameter type is any[]
     // A type annotation for a rest parameter must denote an array type.
     
@@ -37,7 +42,14 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES5i
     
     a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
     a10([1, 2, 3, false, true]);              // Parameter type is any[]
+        ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Types of property '2' are incompatible.
+!!! error TS2345:     Type 'number' is not assignable to type '[[any]]'.
     a10([1, 2]);                              // Parameter type is any[]
+        ~~~~~~
+!!! error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Property '2' is missing in type '[number, number]'.
     a11([1, 2]);                              // Parameter type is number[]
     
     // Rest parameter with generic

tests/baselines/reference/destructuringParameterDeclaration3ES5iterable.types

@@ -52,7 +52,7 @@ function a9([a, b, [[c]]]) { }
 >c : any
 
 function a10([a, b, [[c]], ...x]) { }
->a10 : ([a, b, [[c]], ...x]: any[]) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >a : any
 >b : any
 >c : any
@@ -107,19 +107,19 @@ a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]
 
 a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
 >a10([1, 2, [["string"]], false, true]) : void
->a10 : ([a, b, [[c]], ...x]: any[]) => void
->[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
+>[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
 >1 : 1
 >2 : 2
->[["string"]] : string[][]
->["string"] : string[]
+>[["string"]] : [[string]]
+>["string"] : [string]
 >"string" : "string"
 >false : false
 >true : true
 
 a10([1, 2, 3, false, true]);              // Parameter type is any[]
 >a10([1, 2, 3, false, true]) : void
->a10 : ([a, b, [[c]], ...x]: any[]) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2, 3, false, true] : (number | boolean)[]
 >1 : 1
 >2 : 2
@@ -129,7 +129,7 @@ a10([1, 2, 3, false, true]);              // Parameter type is any[]
 
 a10([1, 2]);                              // Parameter type is any[]
 >a10([1, 2]) : void
->a10 : ([a, b, [[c]], ...x]: any[]) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2] : number[]
 >1 : 1
 >2 : 2

tests/baselines/reference/destructuringParameterDeclaration3ES6.errors.txt

@@ -1,9 +1,14 @@
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts(26,4): error TS2345: Argument of type '[number, number, [[string]], boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]]]'.
   Types of property 'length' are incompatible.
     Type '5' is not assignable to type '3'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts(29,5): error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Types of property '2' are incompatible.
+    Type 'number' is not assignable to type '[[any]]'.
+tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts(30,5): error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+  Property '2' is missing in type '[number, number]'.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts (1 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.ts (3 errors) ====
     // If the parameter is a rest parameter, the parameter type is any[]
     // A type annotation for a rest parameter must denote an array type.
     
@@ -37,7 +42,14 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration3ES6.
     
     a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
     a10([1, 2, 3, false, true]);              // Parameter type is any[]
+        ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type '[number, number, number, boolean, boolean]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Types of property '2' are incompatible.
+!!! error TS2345:     Type 'number' is not assignable to type '[[any]]'.
     a10([1, 2]);                              // Parameter type is any[]
+        ~~~~~~
+!!! error TS2345: Argument of type '[number, number]' is not assignable to parameter of type '[any, any, [[any]], ...any[]]'.
+!!! error TS2345:   Property '2' is missing in type '[number, number]'.
     a11([1, 2]);                              // Parameter type is number[]
     
     // Rest parameter with generic

tests/baselines/reference/destructuringParameterDeclaration3ES6.types

@@ -52,7 +52,7 @@ function a9([a, b, [[c]]]) { }
 >c : any
 
 function a10([a, b, [[c]], ...x]) { }
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >a : any
 >b : any
 >c : any
@@ -107,19 +107,19 @@ a9([1, 2, [["string"]], false, true]);   // Parameter type is [any, any, [[any]]
 
 a10([1, 2, [["string"]], false, true]);   // Parameter type is any[]
 >a10([1, 2, [["string"]], false, true]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
->[1, 2, [["string"]], false, true] : (number | boolean | string[][])[]
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
+>[1, 2, [["string"]], false, true] : [number, number, [[string]], boolean, boolean]
 >1 : 1
 >2 : 2
->[["string"]] : string[][]
->["string"] : string[]
+>[["string"]] : [[string]]
+>["string"] : [string]
 >"string" : "string"
 >false : false
 >true : true
 
 a10([1, 2, 3, false, true]);              // Parameter type is any[]
 >a10([1, 2, 3, false, true]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2, 3, false, true] : (number | boolean)[]
 >1 : 1
 >2 : 2
@@ -129,7 +129,7 @@ a10([1, 2, 3, false, true]);              // Parameter type is any[]
 
 a10([1, 2]);                              // Parameter type is any[]
 >a10([1, 2]) : void
->a10 : ([a, b, [[c]], ...x]: Iterable<any>) => void
+>a10 : ([a, b, [[c]], ...x]: [any, any, [[any]], ...any[]]) => void
 >[1, 2] : number[]
 >1 : 1
 >2 : 2

tests/baselines/reference/destructuringParameterDeclaration4.errors.txt

@@ -1,4 +1,3 @@
-tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(11,13): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(13,13): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(14,17): error TS1047: A rest parameter cannot be optional.
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(15,16): error TS1048: A rest parameter cannot have an initializer.
@@ -17,7 +16,7 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(
 tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(34,28): error TS2304: Cannot find name 'E'.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts (12 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts (11 errors) ====
     // If the parameter is a rest parameter, the parameter type is any[]
     // A type annotation for a rest parameter must denote an array type.
     
@@ -29,8 +28,6 @@ tests/cases/conformance/es6/destructuring/destructuringParameterDeclaration4.ts(
     type stringOrNumArray = Array<String|Number>;
     
     function a0(...x: [number, number, string]) { }  // Error, rest parameter must be array type
-                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2370: A rest parameter must be of an array type.
     function a1(...x: (number|string)[]) { }
     function a2(...a: someArray) { }  // Error, rest parameter must be array type
                 ~~~~~~~~~~~~~~~

tests/baselines/reference/destructuringParameterDeclaration4.types

@@ -22,7 +22,7 @@ type stringOrNumArray = Array<String|Number>;
 >Number : Number
 
 function a0(...x: [number, number, string]) { }  // Error, rest parameter must be array type
->a0 : (...x: [number, number, string]) => void
+>a0 : (x_0: number, x_1: number, x_2: string) => void
 >x : [number, number, string]
 
 function a1(...x: (number|string)[]) { }

tests/baselines/reference/destructuringVariableDeclaration1ES5.types

@@ -113,9 +113,9 @@ var temp1 = [true, false, true]
 >true : true
 
 var [d3, d4] = [1, "string", ...temp1];
->d3 : string | number | boolean
->d4 : string | number | boolean
->[1, "string", ...temp1] : (string | number | boolean)[]
+>d3 : number
+>d4 : string
+>[1, "string", ...temp1] : [number, string, ...boolean[]]
 >1 : 1
 >"string" : "string"
 >...temp1 : boolean
@@ -151,9 +151,9 @@ var {f: [f1, f2, { f3: f4, f5 }, , ]} = { f: [1, 2, { f3: 4, f5: 0 }] };
 >f4 : number
 >f5 : number
 > : undefined
->{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined]; }
->f : [number, number, { f3: number; f5: number; }, undefined]
->[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined]
+>{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined?]; }
+>f : [number, number, { f3: number; f5: number; }, undefined?]
+>[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined?]
 >1 : 1
 >2 : 2
 >{ f3: 4, f5: 0 } : { f3: number; f5: number; }

tests/baselines/reference/destructuringVariableDeclaration1ES5iterable.types

@@ -113,9 +113,9 @@ var temp1 = [true, false, true]
 >true : true
 
 var [d3, d4] = [1, "string", ...temp1];
->d3 : string | number | boolean
->d4 : string | number | boolean
->[1, "string", ...temp1] : (string | number | boolean)[]
+>d3 : number
+>d4 : string
+>[1, "string", ...temp1] : [number, string, ...boolean[]]
 >1 : 1
 >"string" : "string"
 >...temp1 : boolean
@@ -151,9 +151,9 @@ var {f: [f1, f2, { f3: f4, f5 }, , ]} = { f: [1, 2, { f3: 4, f5: 0 }] };
 >f4 : number
 >f5 : number
 > : undefined
->{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined]; }
->f : [number, number, { f3: number; f5: number; }, undefined]
->[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined]
+>{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined?]; }
+>f : [number, number, { f3: number; f5: number; }, undefined?]
+>[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined?]
 >1 : 1
 >2 : 2
 >{ f3: 4, f5: 0 } : { f3: number; f5: number; }

tests/baselines/reference/destructuringVariableDeclaration1ES6.types

@@ -113,9 +113,9 @@ var temp1 = [true, false, true]
 >true : true
 
 var [d3, d4] = [1, "string", ...temp1];
->d3 : string | number | boolean
->d4 : string | number | boolean
->[1, "string", ...temp1] : (string | number | boolean)[]
+>d3 : number
+>d4 : string
+>[1, "string", ...temp1] : [number, string, ...boolean[]]
 >1 : 1
 >"string" : "string"
 >...temp1 : boolean
@@ -151,9 +151,9 @@ var {f: [f1, f2, { f3: f4, f5 }, , ]} = { f: [1, 2, { f3: 4, f5: 0 }] };
 >f4 : number
 >f5 : number
 > : undefined
->{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined]; }
->f : [number, number, { f3: number; f5: number; }, undefined]
->[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined]
+>{ f: [1, 2, { f3: 4, f5: 0 }] } : { f: [number, number, { f3: number; f5: number; }, undefined?]; }
+>f : [number, number, { f3: number; f5: number; }, undefined?]
+>[1, 2, { f3: 4, f5: 0 }] : [number, number, { f3: number; f5: number; }, undefined?]
 >1 : 1
 >2 : 2
 >{ f3: 4, f5: 0 } : { f3: number; f5: number; }

tests/baselines/reference/destructuringVariableDeclaration2.errors.txt

@@ -5,11 +5,9 @@ tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts(4
   Type '[[boolean]]' is not assignable to type '[[string]]'.
     Type '[boolean]' is not assignable to type '[string]'.
       Type 'boolean' is not assignable to type 'string'.
-tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts(14,16): error TS2459: Type 'number | { c3: number; c5: number; }' has no property 'c3' and no string index signature.
-tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts(14,24): error TS2459: Type 'number | { c3: number; c5: number; }' has no property 'c5' and no string index signature.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts (4 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts (2 errors) ====
     // The type T associated with a destructuring variable declaration is determined as follows:
     //      If the declaration includes a type annotation, T is that type.
     var {a1, a2}: { a1: number, a2: string } = { a1: true, a2: 1 }               // Error
@@ -33,10 +31,6 @@ tests/cases/conformance/es6/destructuring/destructuringVariableDeclaration2.ts(1
     //      If the binding element is a rest element, T is an array type with
     //          an element type E, where E is the type of the numeric index signature of S.
     var [c1, c2, { c3: c4, c5 }, , ...c6] = [1, 2, { c3: 4, c5: 0 }];  // Error
-                   ~~
-!!! error TS2459: Type 'number | { c3: number; c5: number; }' has no property 'c3' and no string index signature.
-                           ~~
-!!! error TS2459: Type 'number | { c3: number; c5: number; }' has no property 'c5' and no string index signature.
     
     // When a destructuring variable declaration, binding property, or binding element specifies
     // an initializer expression, the type of the initializer expression is required to be assignable

tests/baselines/reference/destructuringVariableDeclaration2.symbols

@@ -35,6 +35,7 @@ var [b0 = 3, b1 = true, b2 = temp] = [3, false, { t1: false, t2: 5}];  // Error
 var [c1, c2, { c3: c4, c5 }, , ...c6] = [1, 2, { c3: 4, c5: 0 }];  // Error
 >c1 : Symbol(c1, Decl(destructuringVariableDeclaration2.ts, 13, 5))
 >c2 : Symbol(c2, Decl(destructuringVariableDeclaration2.ts, 13, 8))
+>c3 : Symbol(c3, Decl(destructuringVariableDeclaration2.ts, 13, 48))
 >c4 : Symbol(c4, Decl(destructuringVariableDeclaration2.ts, 13, 14))
 >c5 : Symbol(c5, Decl(destructuringVariableDeclaration2.ts, 13, 22))
 >c6 : Symbol(c6, Decl(destructuringVariableDeclaration2.ts, 13, 30))

tests/baselines/reference/destructuringVariableDeclaration2.types

@@ -53,14 +53,14 @@ var [b0 = 3, b1 = true, b2 = temp] = [3, false, { t1: false, t2: 5}];  // Error
 //      If the binding element is a rest element, T is an array type with
 //          an element type E, where E is the type of the numeric index signature of S.
 var [c1, c2, { c3: c4, c5 }, , ...c6] = [1, 2, { c3: 4, c5: 0 }];  // Error
->c1 : number | { c3: number; c5: number; }
->c2 : number | { c3: number; c5: number; }
+>c1 : number
+>c2 : number
 >c3 : any
->c4 : any
->c5 : any
+>c4 : number
+>c5 : number
 > : undefined
->c6 : (number | { c3: number; c5: number; })[]
->[1, 2, { c3: 4, c5: 0 }] : (number | { c3: number; c5: number; })[]
+>c6 : any[]
+>[1, 2, { c3: 4, c5: 0 }] : [number, number, { c3: number; c5: number; }, undefined?]
 >1 : 1
 >2 : 2
 >{ c3: 4, c5: 0 } : { c3: number; c5: number; }

tests/baselines/reference/destructuringWithLiteralInitializers.types

@@ -235,7 +235,7 @@ g1([1, 1]);
 
 // (arg: [number, number]) => void
 function g2([x = 0, y = 0]) { }
->g2 : ([x, y]: [number, number]) => void
+>g2 : ([x, y]: [number?, number?]) => void
 >x : number
 >0 : 0
 >y : number
@@ -243,7 +243,7 @@ function g2([x = 0, y = 0]) { }
 
 g2([1, 1]);
 >g2([1, 1]) : void
->g2 : ([x, y]: [number, number]) => void
+>g2 : ([x, y]: [number?, number?]) => void
 >[1, 1] : [number, number]
 >1 : 1
 >1 : 1
@@ -270,40 +270,40 @@ g3([1, 1]);
 
 // (arg?: [number, number]) => void
 function g4([x, y = 0] = [0]) { }
->g4 : ([x, y]?: [number, number]) => void
+>g4 : ([x, y]?: [number, number?]) => void
 >x : number
 >y : number
 >0 : 0
->[0] : [number, number]
+>[0] : [number, number?]
 >0 : 0
 
 g4();
 >g4() : void
->g4 : ([x, y]?: [number, number]) => void
+>g4 : ([x, y]?: [number, number?]) => void
 
 g4([1, 1]);
 >g4([1, 1]) : void
->g4 : ([x, y]?: [number, number]) => void
+>g4 : ([x, y]?: [number, number?]) => void
 >[1, 1] : [number, number]
 >1 : 1
 >1 : 1
 
 // (arg?: [number, number]) => void
 function g5([x = 0, y = 0] = []) { }
->g5 : ([x, y]?: [number, number]) => void
+>g5 : ([x, y]?: [number?, number?]) => void
 >x : number
 >0 : 0
 >y : number
 >0 : 0
->[] : [number, number]
+>[] : [number?, number?]
 
 g5();
 >g5() : void
->g5 : ([x, y]?: [number, number]) => void
+>g5 : ([x, y]?: [number?, number?]) => void
 
 g5([1, 1]);
 >g5([1, 1]) : void
->g5 : ([x, y]?: [number, number]) => void
+>g5 : ([x, y]?: [number?, number?]) => void
 >[1, 1] : [number, number]
 >1 : 1
 >1 : 1

tests/baselines/reference/downlevelLetConst12.types

@@ -12,7 +12,7 @@ const bar = 1;
 
 let [baz] = [];
 >baz : any
->[] : [undefined]
+>[] : [undefined?]
 
 let {a: baz2} = { a: 1 };
 >a : any
@@ -23,7 +23,7 @@ let {a: baz2} = { a: 1 };
 
 const [baz3] = []
 >baz3 : any
->[] : [undefined]
+>[] : [undefined?]
 
 const {a: baz4} = { a: 1 };
 >a : any

tests/baselines/reference/downlevelLetConst16.types

@@ -516,7 +516,7 @@ function foo3() {
     }
     for (let [y] = []; ;) {
 >y : any
->[] : [undefined]
+>[] : [undefined?]
 
         use(y);
 >use(y) : any
@@ -555,7 +555,7 @@ function foo4() {
     }
     for (const [y] = []; ;) {
 >y : any
->[] : [undefined]
+>[] : [undefined?]
 
         use(y);
 >use(y) : any

tests/baselines/reference/duplicateIdentifierBindingElementInParameterDeclaration1.types

@@ -40,7 +40,7 @@ function f5({e, e: {e}}, {e}, [d,e, [[e]]], ...e) { }
 >e : any[]
 
 function f6([f, ...f]) { }
->f6 : ([f, ...f]: any[]) => void
+>f6 : ([f, ...f]: [any, ...any[]]) => void
 >f : any
 >f : any[]
 

tests/baselines/reference/duplicateIdentifierBindingElementInParameterDeclaration2.types

@@ -43,7 +43,7 @@ function f5({e, e: {e}}, {e}, [d, e, [[e]]], ...e) { }
 >e : any[]
 
 function f6([f, ...f]) { }
->f6 : ([f, ...f]: any[]) => void
+>f6 : ([f, ...f]: [any, ...any[]]) => void
 >f : any
 >f : any[]
 

tests/baselines/reference/emitArrowFunctionES6.types

@@ -58,14 +58,14 @@ var p3 = ([, a]) => { };
 >a : any
 
 var p4 = ([, ...a]) => { };
->p4 : ([, ...a]: Iterable<any>) => void
->([, ...a]) => { } : ([, ...a]: Iterable<any>) => void
+>p4 : ([, ...a]: [any?, ...any[]]) => void
+>([, ...a]) => { } : ([, ...a]: [any?, ...any[]]) => void
 > : undefined
 >a : any[]
 
 var p5 = ([a = 1]) => { };
->p5 : ([a]: [number]) => void
->([a = 1]) => { } : ([a]: [number]) => void
+>p5 : ([a]: [number?]) => void
+>([a = 1]) => { } : ([a]: [number?]) => void
 >a : number
 >1 : 1
 

tests/baselines/reference/emptyTuplesTypeAssertion01.errors.txt

@@ -1,8 +0,0 @@
-tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion01.ts(1,10): error TS1122: A tuple type element list cannot be empty.
-
-
-==== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion01.ts (1 errors) ====
-    let x = <[]>[];
-             ~~
-!!! error TS1122: A tuple type element list cannot be empty.
-    let y = x[0];

tests/baselines/reference/emptyTuplesTypeAssertion01.types

@@ -2,7 +2,7 @@
 let x = <[]>[];
 >x : []
 ><[]>[] : []
->[] : undefined[]
+>[] : []
 
 let y = x[0];
 >y : never

tests/baselines/reference/emptyTuplesTypeAssertion02.errors.txt

@@ -1,8 +0,0 @@
-tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion02.ts(1,15): error TS1122: A tuple type element list cannot be empty.
-
-
-==== tests/cases/conformance/types/tuple/emptyTuples/emptyTuplesTypeAssertion02.ts (1 errors) ====
-    let x = [] as [];
-                  ~~
-!!! error TS1122: A tuple type element list cannot be empty.
-    let y = x[0];

tests/baselines/reference/emptyTuplesTypeAssertion02.types

@@ -2,7 +2,7 @@
 let x = [] as [];
 >x : []
 >[] as [] : []
->[] : undefined[]
+>[] : []
 
 let y = x[0];
 >y : never

tests/baselines/reference/for-of49.errors.txt

@@ -1,14 +0,0 @@
-tests/cases/conformance/es6/for-ofStatements/for-of49.ts(3,14): error TS2322: Type 'string | boolean' is not assignable to type 'boolean'.
-  Type 'string' is not assignable to type 'boolean'.
-
-
-==== tests/cases/conformance/es6/for-ofStatements/for-of49.ts (1 errors) ====
-    var k: string, v: boolean;
-    var map = new Map([["", true]]);
-    for ([k, ...[v]] of map) {
-                 ~
-!!! error TS2322: Type 'string | boolean' is not assignable to type 'boolean'.
-!!! error TS2322:   Type 'string' is not assignable to type 'boolean'.
-        k;
-        v;
-    }

tests/baselines/reference/for-of49.types

@@ -13,7 +13,7 @@ var map = new Map([["", true]]);
 >true : true
 
 for ([k, ...[v]] of map) {
->[k, ...[v]] : (string | boolean)[]
+>[k, ...[v]] : [string, ...boolean[]]
 >k : string
 >...[v] : boolean
 >[v] : [boolean]

tests/baselines/reference/genericRestParameters1.errors.txt

@@ -0,0 +1,164 @@
+tests/cases/conformance/types/rest/genericRestParameters1.ts(22,1): error TS2556: Expected 3 arguments, but got 1 or more.
+tests/cases/conformance/types/rest/genericRestParameters1.ts(31,1): error TS2556: Expected 3 arguments, but got 1 or more.
+
+
+==== tests/cases/conformance/types/rest/genericRestParameters1.ts (2 errors) ====
+    declare let f1: (...x: [number, string, boolean]) => void;
+    declare let f2: (x0: number, x1: string, x2: boolean) => void;
+    
+    f1 = f2;
+    f2 = f1;
+    
+    declare const t3: [number, string, boolean];
+    declare const t2: [string, boolean];
+    declare const t1: [boolean];
+    declare const t0: [];
+    
+    declare const ns: [number, string];
+    declare const sn: [string, number];
+    
+    f1(42, "hello", true);
+    f1(t3[0], t3[1], t3[2]);
+    f1(...t3);
+    f1(42, ...t2);
+    f1(42, "hello", ...t1);
+    f1(42, "hello", true, ...t0);
+    f1(ns[0], ns[1], true);
+    f1(...ns, true);  // Error, tuple spread only expanded when last
+    ~~~~~~~~~~~~~~~
+!!! error TS2556: Expected 3 arguments, but got 1 or more.
+    
+    f2(42, "hello", true);
+    f2(t3[0], t3[1], t3[2]);
+    f2(...t3);
+    f2(42, ...t2);
+    f2(42, "hello", ...t1);
+    f2(42, "hello", true, ...t0);
+    f2(ns[0], ns[1], true);
+    f2(...ns, true);  // Error, tuple spread only expanded when last
+    ~~~~~~~~~~~~~~~
+!!! error TS2556: Expected 3 arguments, but got 1 or more.
+    
+    declare function f10<T extends unknown[]>(...args: T): T;
+    
+    const x10 = f10(42, "hello", true);  // [number, string, boolean]
+    const x11 = f10(42, "hello");  // [number, string]
+    const x12 = f10(42);  // [number]
+    const x13 = f10();  // []
+    const x14 = f10(...t3);  // [number, string, boolean]
+    const x15 = f10(42, ...t2);  // [number, string, boolean]
+    const x16 = f10(42, "hello", ...t1);  // [number, string, boolean]
+    const x17 = f10(42, "hello", true, ...t0);  // [number, string, boolean]
+    const x18 = f10(...ns, true);  // (string | number | boolean)[]
+    
+    function g10<U extends string[], V extends [number, number]>(u: U, v: V) {
+        let x1 = f10(...u);  // U
+        let x2 = f10(...v);  // V
+        let x3 = f10(1, ...u);  // [number, ...string[]]
+        let x4 = f10(...u, ...v);  // (string | number)[]
+    }
+    
+    declare function f11<T extends (string | number | boolean)[]>(...args: T): T;
+    
+    const z10 = f11(42, "hello", true);  // [42, "hello", true]
+    const z11 = f11(42, "hello");  // [42, "hello"]
+    const z12 = f11(42);  // [42]
+    const z13 = f11();  // []
+    const z14 = f11(...t3);  // [number, string, boolean]
+    const z15 = f11(42, ...t2);  // [42, string, boolean]
+    const z16 = f11(42, "hello", ...t1);  // [42, "hello", boolean]
+    const z17 = f11(42, "hello", true, ...t0);  // [42, "hello", true]
+    const z18 = f11(...ns, true);  // (string | number | true)[]
+    
+    function g11<U extends string[], V extends [number, number]>(u: U, v: V) {
+        let x1 = f11(...u);  // U
+        let x2 = f11(...v);  // V
+        let x3 = f11(1, ...u);  // [1, ...string[]]
+        let x4 = f11(...u, ...v);  // (string | number)[]
+    }
+    
+    function call<T extends unknown[], U>(f: (...args: T) => U, ...args: T) {
+        return f(...args);
+    }
+    
+    function callr<T extends unknown[], U>(args: T, f: (...args: T) => U) {
+        return f(...args);
+    }
+    
+    declare function f15(a: string, b: number): string | number;
+    declare function f16<A, B>(a: A, b: B): A | B;
+    
+    let x20 = call((x, y) => x + y, 10, 20);  // number
+    let x21 = call((x, y) => x + y, 10, "hello");  // string
+    let x22 = call(f15, "hello", 42);  // string | number
+    let x23 = call(f16, "hello", 42);  // unknown
+    let x24 = call<[string, number], string | number>(f16, "hello", 42);  // string | number
+    
+    let x30 = callr(sn, (x, y) => x + y);  // string
+    let x31 = callr(sn, f15);  // string | number
+    let x32 = callr(sn, f16);  // string | number
+    
+    function bind<T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) {
+        return (...rest: U) => f(x, ...rest);
+    }
+    
+    declare const f20: (x: number, y: string, z: boolean) => string[];
+    
+    const f21 = bind(f20, 42);  // (y: string, z: boolean) => string[]
+    const f22 = bind(f21, "hello");  // (z: boolean) => string[]
+    const f23 = bind(f22, true);  // () => string[]
+    
+    f20(42, "hello", true);
+    f21("hello", true);
+    f22(true);
+    f23();
+    
+    declare const g20: (x: number, y?: string, z?: boolean) => string[];
+    
+    const g21 = bind(g20, 42);  // (y: string, z: boolean) => string[]
+    const g22 = bind(g21, "hello");  // (z: boolean) => string[]
+    const g23 = bind(g22, true);  // () => string[]
+    
+    g20(42, "hello", true);
+    g20(42, "hello");
+    g20(42);
+    g21("hello", true);
+    g21("hello");
+    g21();
+    g22(true);
+    g22();
+    g23();
+    
+    declare function f30<T, U extends ((x: T) => any)[]>(x: T, ...args: U): U;
+    
+    const c30 = f30(42, x => "" + x, x => x + 1);  // [(x: number) => string, (x: number) => number]
+    
+    type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+    
+    type T01 = Parameters<(x: number, y: string, z: boolean) => void>;
+    type T02 = Parameters<(...args: [number, string, boolean]) => void>;
+    type T03 = Parameters<new (x: number, y: string, z: boolean) => void>;
+    type T04 = Parameters<new (...args: [number, string, boolean]) => void>;
+    type T05<T> = Parameters<(...args: T[]) => void>;
+    type T06<T> = Parameters<new (...args: []) => void>;
+    type T07<T extends any[]> = Parameters<(...args: T) => void>;
+    type T08<T extends any[]> = Parameters<new (...args: T) => void>;
+    type T09 = Parameters<Function>;
+    
+    type Record1 = {
+      move: [number, 'left' | 'right'];
+      jump: [number, 'up' | 'down'];
+      stop: string;
+      done: [];
+    }
+    
+    type EventType<T> = {
+      emit<K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]): void; 
+    }
+    
+    declare var events: EventType<Record1>;
+    events.emit('move', 10, 'left');
+    events.emit('jump', 20, 'up');
+    events.emit('stop', 'Bye!');
+    events.emit('done');
+    

tests/baselines/reference/genericRestParameters1.js

@@ -0,0 +1,334 @@
+//// [genericRestParameters1.ts]
+declare let f1: (...x: [number, string, boolean]) => void;
+declare let f2: (x0: number, x1: string, x2: boolean) => void;
+
+f1 = f2;
+f2 = f1;
+
+declare const t3: [number, string, boolean];
+declare const t2: [string, boolean];
+declare const t1: [boolean];
+declare const t0: [];
+
+declare const ns: [number, string];
+declare const sn: [string, number];
+
+f1(42, "hello", true);
+f1(t3[0], t3[1], t3[2]);
+f1(...t3);
+f1(42, ...t2);
+f1(42, "hello", ...t1);
+f1(42, "hello", true, ...t0);
+f1(ns[0], ns[1], true);
+f1(...ns, true);  // Error, tuple spread only expanded when last
+
+f2(42, "hello", true);
+f2(t3[0], t3[1], t3[2]);
+f2(...t3);
+f2(42, ...t2);
+f2(42, "hello", ...t1);
+f2(42, "hello", true, ...t0);
+f2(ns[0], ns[1], true);
+f2(...ns, true);  // Error, tuple spread only expanded when last
+
+declare function f10<T extends unknown[]>(...args: T): T;
+
+const x10 = f10(42, "hello", true);  // [number, string, boolean]
+const x11 = f10(42, "hello");  // [number, string]
+const x12 = f10(42);  // [number]
+const x13 = f10();  // []
+const x14 = f10(...t3);  // [number, string, boolean]
+const x15 = f10(42, ...t2);  // [number, string, boolean]
+const x16 = f10(42, "hello", ...t1);  // [number, string, boolean]
+const x17 = f10(42, "hello", true, ...t0);  // [number, string, boolean]
+const x18 = f10(...ns, true);  // (string | number | boolean)[]
+
+function g10<U extends string[], V extends [number, number]>(u: U, v: V) {
+    let x1 = f10(...u);  // U
+    let x2 = f10(...v);  // V
+    let x3 = f10(1, ...u);  // [number, ...string[]]
+    let x4 = f10(...u, ...v);  // (string | number)[]
+}
+
+declare function f11<T extends (string | number | boolean)[]>(...args: T): T;
+
+const z10 = f11(42, "hello", true);  // [42, "hello", true]
+const z11 = f11(42, "hello");  // [42, "hello"]
+const z12 = f11(42);  // [42]
+const z13 = f11();  // []
+const z14 = f11(...t3);  // [number, string, boolean]
+const z15 = f11(42, ...t2);  // [42, string, boolean]
+const z16 = f11(42, "hello", ...t1);  // [42, "hello", boolean]
+const z17 = f11(42, "hello", true, ...t0);  // [42, "hello", true]
+const z18 = f11(...ns, true);  // (string | number | true)[]
+
+function g11<U extends string[], V extends [number, number]>(u: U, v: V) {
+    let x1 = f11(...u);  // U
+    let x2 = f11(...v);  // V
+    let x3 = f11(1, ...u);  // [1, ...string[]]
+    let x4 = f11(...u, ...v);  // (string | number)[]
+}
+
+function call<T extends unknown[], U>(f: (...args: T) => U, ...args: T) {
+    return f(...args);
+}
+
+function callr<T extends unknown[], U>(args: T, f: (...args: T) => U) {
+    return f(...args);
+}
+
+declare function f15(a: string, b: number): string | number;
+declare function f16<A, B>(a: A, b: B): A | B;
+
+let x20 = call((x, y) => x + y, 10, 20);  // number
+let x21 = call((x, y) => x + y, 10, "hello");  // string
+let x22 = call(f15, "hello", 42);  // string | number
+let x23 = call(f16, "hello", 42);  // unknown
+let x24 = call<[string, number], string | number>(f16, "hello", 42);  // string | number
+
+let x30 = callr(sn, (x, y) => x + y);  // string
+let x31 = callr(sn, f15);  // string | number
+let x32 = callr(sn, f16);  // string | number
+
+function bind<T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) {
+    return (...rest: U) => f(x, ...rest);
+}
+
+declare const f20: (x: number, y: string, z: boolean) => string[];
+
+const f21 = bind(f20, 42);  // (y: string, z: boolean) => string[]
+const f22 = bind(f21, "hello");  // (z: boolean) => string[]
+const f23 = bind(f22, true);  // () => string[]
+
+f20(42, "hello", true);
+f21("hello", true);
+f22(true);
+f23();
+
+declare const g20: (x: number, y?: string, z?: boolean) => string[];
+
+const g21 = bind(g20, 42);  // (y: string, z: boolean) => string[]
+const g22 = bind(g21, "hello");  // (z: boolean) => string[]
+const g23 = bind(g22, true);  // () => string[]
+
+g20(42, "hello", true);
+g20(42, "hello");
+g20(42);
+g21("hello", true);
+g21("hello");
+g21();
+g22(true);
+g22();
+g23();
+
+declare function f30<T, U extends ((x: T) => any)[]>(x: T, ...args: U): U;
+
+const c30 = f30(42, x => "" + x, x => x + 1);  // [(x: number) => string, (x: number) => number]
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+
+type T01 = Parameters<(x: number, y: string, z: boolean) => void>;
+type T02 = Parameters<(...args: [number, string, boolean]) => void>;
+type T03 = Parameters<new (x: number, y: string, z: boolean) => void>;
+type T04 = Parameters<new (...args: [number, string, boolean]) => void>;
+type T05<T> = Parameters<(...args: T[]) => void>;
+type T06<T> = Parameters<new (...args: []) => void>;
+type T07<T extends any[]> = Parameters<(...args: T) => void>;
+type T08<T extends any[]> = Parameters<new (...args: T) => void>;
+type T09 = Parameters<Function>;
+
+type Record1 = {
+  move: [number, 'left' | 'right'];
+  jump: [number, 'up' | 'down'];
+  stop: string;
+  done: [];
+}
+
+type EventType<T> = {
+  emit<K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]): void; 
+}
+
+declare var events: EventType<Record1>;
+events.emit('move', 10, 'left');
+events.emit('jump', 20, 'up');
+events.emit('stop', 'Bye!');
+events.emit('done');
+
+
+//// [genericRestParameters1.js]
+"use strict";
+f1 = f2;
+f2 = f1;
+f1(42, "hello", true);
+f1(t3[0], t3[1], t3[2]);
+f1.apply(void 0, t3);
+f1.apply(void 0, [42].concat(t2));
+f1.apply(void 0, [42, "hello"].concat(t1));
+f1.apply(void 0, [42, "hello", true].concat(t0));
+f1(ns[0], ns[1], true);
+f1.apply(void 0, ns.concat([true])); // Error, tuple spread only expanded when last
+f2(42, "hello", true);
+f2(t3[0], t3[1], t3[2]);
+f2.apply(void 0, t3);
+f2.apply(void 0, [42].concat(t2));
+f2.apply(void 0, [42, "hello"].concat(t1));
+f2.apply(void 0, [42, "hello", true].concat(t0));
+f2(ns[0], ns[1], true);
+f2.apply(void 0, ns.concat([true])); // Error, tuple spread only expanded when last
+var x10 = f10(42, "hello", true); // [number, string, boolean]
+var x11 = f10(42, "hello"); // [number, string]
+var x12 = f10(42); // [number]
+var x13 = f10(); // []
+var x14 = f10.apply(void 0, t3); // [number, string, boolean]
+var x15 = f10.apply(void 0, [42].concat(t2)); // [number, string, boolean]
+var x16 = f10.apply(void 0, [42, "hello"].concat(t1)); // [number, string, boolean]
+var x17 = f10.apply(void 0, [42, "hello", true].concat(t0)); // [number, string, boolean]
+var x18 = f10.apply(void 0, ns.concat([true])); // (string | number | boolean)[]
+function g10(u, v) {
+    var x1 = f10.apply(void 0, u); // U
+    var x2 = f10.apply(void 0, v); // V
+    var x3 = f10.apply(void 0, [1].concat(u)); // [number, ...string[]]
+    var x4 = f10.apply(void 0, u.concat(v)); // (string | number)[]
+}
+var z10 = f11(42, "hello", true); // [42, "hello", true]
+var z11 = f11(42, "hello"); // [42, "hello"]
+var z12 = f11(42); // [42]
+var z13 = f11(); // []
+var z14 = f11.apply(void 0, t3); // [number, string, boolean]
+var z15 = f11.apply(void 0, [42].concat(t2)); // [42, string, boolean]
+var z16 = f11.apply(void 0, [42, "hello"].concat(t1)); // [42, "hello", boolean]
+var z17 = f11.apply(void 0, [42, "hello", true].concat(t0)); // [42, "hello", true]
+var z18 = f11.apply(void 0, ns.concat([true])); // (string | number | true)[]
+function g11(u, v) {
+    var x1 = f11.apply(void 0, u); // U
+    var x2 = f11.apply(void 0, v); // V
+    var x3 = f11.apply(void 0, [1].concat(u)); // [1, ...string[]]
+    var x4 = f11.apply(void 0, u.concat(v)); // (string | number)[]
+}
+function call(f) {
+    var args = [];
+    for (var _i = 1; _i < arguments.length; _i++) {
+        args[_i - 1] = arguments[_i];
+    }
+    return f.apply(void 0, args);
+}
+function callr(args, f) {
+    return f.apply(void 0, args);
+}
+var x20 = call(function (x, y) { return x + y; }, 10, 20); // number
+var x21 = call(function (x, y) { return x + y; }, 10, "hello"); // string
+var x22 = call(f15, "hello", 42); // string | number
+var x23 = call(f16, "hello", 42); // unknown
+var x24 = call(f16, "hello", 42); // string | number
+var x30 = callr(sn, function (x, y) { return x + y; }); // string
+var x31 = callr(sn, f15); // string | number
+var x32 = callr(sn, f16); // string | number
+function bind(f, x) {
+    return function () {
+        var rest = [];
+        for (var _i = 0; _i < arguments.length; _i++) {
+            rest[_i] = arguments[_i];
+        }
+        return f.apply(void 0, [x].concat(rest));
+    };
+}
+var f21 = bind(f20, 42); // (y: string, z: boolean) => string[]
+var f22 = bind(f21, "hello"); // (z: boolean) => string[]
+var f23 = bind(f22, true); // () => string[]
+f20(42, "hello", true);
+f21("hello", true);
+f22(true);
+f23();
+var g21 = bind(g20, 42); // (y: string, z: boolean) => string[]
+var g22 = bind(g21, "hello"); // (z: boolean) => string[]
+var g23 = bind(g22, true); // () => string[]
+g20(42, "hello", true);
+g20(42, "hello");
+g20(42);
+g21("hello", true);
+g21("hello");
+g21();
+g22(true);
+g22();
+g23();
+var c30 = f30(42, function (x) { return "" + x; }, function (x) { return x + 1; }); // [(x: number) => string, (x: number) => number]
+events.emit('move', 10, 'left');
+events.emit('jump', 20, 'up');
+events.emit('stop', 'Bye!');
+events.emit('done');
+
+
+//// [genericRestParameters1.d.ts]
+declare let f1: (...x: [number, string, boolean]) => void;
+declare let f2: (x0: number, x1: string, x2: boolean) => void;
+declare const t3: [number, string, boolean];
+declare const t2: [string, boolean];
+declare const t1: [boolean];
+declare const t0: [];
+declare const ns: [number, string];
+declare const sn: [string, number];
+declare function f10<T extends unknown[]>(...args: T): T;
+declare const x10: [number, string, boolean];
+declare const x11: [number, string];
+declare const x12: [number];
+declare const x13: [];
+declare const x14: [number, string, boolean];
+declare const x15: [number, string, boolean];
+declare const x16: [number, string, boolean];
+declare const x17: [number, string, boolean];
+declare const x18: (string | number | boolean)[];
+declare function g10<U extends string[], V extends [number, number]>(u: U, v: V): void;
+declare function f11<T extends (string | number | boolean)[]>(...args: T): T;
+declare const z10: [42, "hello", true];
+declare const z11: [42, "hello"];
+declare const z12: [42];
+declare const z13: [];
+declare const z14: [number, string, boolean];
+declare const z15: [42, string, boolean];
+declare const z16: [42, "hello", boolean];
+declare const z17: [42, "hello", true];
+declare const z18: (string | number | true)[];
+declare function g11<U extends string[], V extends [number, number]>(u: U, v: V): void;
+declare function call<T extends unknown[], U>(f: (...args: T) => U, ...args: T): U;
+declare function callr<T extends unknown[], U>(args: T, f: (...args: T) => U): U;
+declare function f15(a: string, b: number): string | number;
+declare function f16<A, B>(a: A, b: B): A | B;
+declare let x20: number;
+declare let x21: string;
+declare let x22: string | number;
+declare let x23: unknown;
+declare let x24: string | number;
+declare let x30: string;
+declare let x31: string | number;
+declare let x32: string | number;
+declare function bind<T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T): (...rest: U) => V;
+declare const f20: (x: number, y: string, z: boolean) => string[];
+declare const f21: (y: string, z: boolean) => string[];
+declare const f22: (z: boolean) => string[];
+declare const f23: () => string[];
+declare const g20: (x: number, y?: string, z?: boolean) => string[];
+declare const g21: (y?: string | undefined, z?: boolean | undefined) => string[];
+declare const g22: (z?: boolean | undefined) => string[];
+declare const g23: () => string[];
+declare function f30<T, U extends ((x: T) => any)[]>(x: T, ...args: U): U;
+declare const c30: [(x: number) => string, (x: number) => number];
+declare type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new (...args: infer U) => any) ? U : any[];
+declare type T01 = Parameters<(x: number, y: string, z: boolean) => void>;
+declare type T02 = Parameters<(...args: [number, string, boolean]) => void>;
+declare type T03 = Parameters<new (x: number, y: string, z: boolean) => void>;
+declare type T04 = Parameters<new (...args: [number, string, boolean]) => void>;
+declare type T05<T> = Parameters<(...args: T[]) => void>;
+declare type T06<T> = Parameters<new (...args: []) => void>;
+declare type T07<T extends any[]> = Parameters<(...args: T) => void>;
+declare type T08<T extends any[]> = Parameters<new (...args: T) => void>;
+declare type T09 = Parameters<Function>;
+declare type Record1 = {
+    move: [number, 'left' | 'right'];
+    jump: [number, 'up' | 'down'];
+    stop: string;
+    done: [];
+};
+declare type EventType<T> = {
+    emit<K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]): void;
+};
+declare var events: EventType<Record1>;

tests/baselines/reference/genericRestParameters1.symbols

@@ -0,0 +1,624 @@
+=== tests/cases/conformance/types/rest/genericRestParameters1.ts ===
+declare let f1: (...x: [number, string, boolean]) => void;
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 0, 17))
+
+declare let f2: (x0: number, x1: string, x2: boolean) => void;
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>x0 : Symbol(x0, Decl(genericRestParameters1.ts, 1, 17))
+>x1 : Symbol(x1, Decl(genericRestParameters1.ts, 1, 28))
+>x2 : Symbol(x2, Decl(genericRestParameters1.ts, 1, 40))
+
+f1 = f2;
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+
+f2 = f1;
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+
+declare const t3: [number, string, boolean];
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+
+declare const t2: [string, boolean];
+>t2 : Symbol(t2, Decl(genericRestParameters1.ts, 7, 13))
+
+declare const t1: [boolean];
+>t1 : Symbol(t1, Decl(genericRestParameters1.ts, 8, 13))
+
+declare const t0: [];
+>t0 : Symbol(t0, Decl(genericRestParameters1.ts, 9, 13))
+
+declare const ns: [number, string];
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+
+declare const sn: [string, number];
+>sn : Symbol(sn, Decl(genericRestParameters1.ts, 12, 13))
+
+f1(42, "hello", true);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+
+f1(t3[0], t3[1], t3[2]);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>0 : Symbol(0)
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>1 : Symbol(1)
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>2 : Symbol(2)
+
+f1(...t3);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+
+f1(42, ...t2);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters1.ts, 7, 13))
+
+f1(42, "hello", ...t1);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters1.ts, 8, 13))
+
+f1(42, "hello", true, ...t0);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>t0 : Symbol(t0, Decl(genericRestParameters1.ts, 9, 13))
+
+f1(ns[0], ns[1], true);
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+>0 : Symbol(0)
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+>1 : Symbol(1)
+
+f1(...ns, true);  // Error, tuple spread only expanded when last
+>f1 : Symbol(f1, Decl(genericRestParameters1.ts, 0, 11))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+
+f2(42, "hello", true);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+
+f2(t3[0], t3[1], t3[2]);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>0 : Symbol(0)
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>1 : Symbol(1)
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+>2 : Symbol(2)
+
+f2(...t3);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+
+f2(42, ...t2);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters1.ts, 7, 13))
+
+f2(42, "hello", ...t1);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters1.ts, 8, 13))
+
+f2(42, "hello", true, ...t0);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>t0 : Symbol(t0, Decl(genericRestParameters1.ts, 9, 13))
+
+f2(ns[0], ns[1], true);
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+>0 : Symbol(0)
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+>1 : Symbol(1)
+
+f2(...ns, true);  // Error, tuple spread only expanded when last
+>f2 : Symbol(f2, Decl(genericRestParameters1.ts, 1, 11))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+
+declare function f10<T extends unknown[]>(...args: T): T;
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 32, 21))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 32, 42))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 32, 21))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 32, 21))
+
+const x10 = f10(42, "hello", true);  // [number, string, boolean]
+>x10 : Symbol(x10, Decl(genericRestParameters1.ts, 34, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+
+const x11 = f10(42, "hello");  // [number, string]
+>x11 : Symbol(x11, Decl(genericRestParameters1.ts, 35, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+
+const x12 = f10(42);  // [number]
+>x12 : Symbol(x12, Decl(genericRestParameters1.ts, 36, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+
+const x13 = f10();  // []
+>x13 : Symbol(x13, Decl(genericRestParameters1.ts, 37, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+
+const x14 = f10(...t3);  // [number, string, boolean]
+>x14 : Symbol(x14, Decl(genericRestParameters1.ts, 38, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+
+const x15 = f10(42, ...t2);  // [number, string, boolean]
+>x15 : Symbol(x15, Decl(genericRestParameters1.ts, 39, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>t2 : Symbol(t2, Decl(genericRestParameters1.ts, 7, 13))
+
+const x16 = f10(42, "hello", ...t1);  // [number, string, boolean]
+>x16 : Symbol(x16, Decl(genericRestParameters1.ts, 40, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>t1 : Symbol(t1, Decl(genericRestParameters1.ts, 8, 13))
+
+const x17 = f10(42, "hello", true, ...t0);  // [number, string, boolean]
+>x17 : Symbol(x17, Decl(genericRestParameters1.ts, 41, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>t0 : Symbol(t0, Decl(genericRestParameters1.ts, 9, 13))
+
+const x18 = f10(...ns, true);  // (string | number | boolean)[]
+>x18 : Symbol(x18, Decl(genericRestParameters1.ts, 42, 5))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+
+function g10<U extends string[], V extends [number, number]>(u: U, v: V) {
+>g10 : Symbol(g10, Decl(genericRestParameters1.ts, 42, 29))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 44, 13))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 44, 32))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 44, 61))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 44, 13))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 44, 66))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 44, 32))
+
+    let x1 = f10(...u);  // U
+>x1 : Symbol(x1, Decl(genericRestParameters1.ts, 45, 7))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 44, 61))
+
+    let x2 = f10(...v);  // V
+>x2 : Symbol(x2, Decl(genericRestParameters1.ts, 46, 7))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 44, 66))
+
+    let x3 = f10(1, ...u);  // [number, ...string[]]
+>x3 : Symbol(x3, Decl(genericRestParameters1.ts, 47, 7))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 44, 61))
+
+    let x4 = f10(...u, ...v);  // (string | number)[]
+>x4 : Symbol(x4, Decl(genericRestParameters1.ts, 48, 7))
+>f10 : Symbol(f10, Decl(genericRestParameters1.ts, 30, 16))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 44, 61))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 44, 66))
+}
+
+declare function f11<T extends (string | number | boolean)[]>(...args: T): T;
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 51, 21))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 51, 62))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 51, 21))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 51, 21))
+
+const z10 = f11(42, "hello", true);  // [42, "hello", true]
+>z10 : Symbol(z10, Decl(genericRestParameters1.ts, 53, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+
+const z11 = f11(42, "hello");  // [42, "hello"]
+>z11 : Symbol(z11, Decl(genericRestParameters1.ts, 54, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+
+const z12 = f11(42);  // [42]
+>z12 : Symbol(z12, Decl(genericRestParameters1.ts, 55, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+
+const z13 = f11();  // []
+>z13 : Symbol(z13, Decl(genericRestParameters1.ts, 56, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+
+const z14 = f11(...t3);  // [number, string, boolean]
+>z14 : Symbol(z14, Decl(genericRestParameters1.ts, 57, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>t3 : Symbol(t3, Decl(genericRestParameters1.ts, 6, 13))
+
+const z15 = f11(42, ...t2);  // [42, string, boolean]
+>z15 : Symbol(z15, Decl(genericRestParameters1.ts, 58, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>t2 : Symbol(t2, Decl(genericRestParameters1.ts, 7, 13))
+
+const z16 = f11(42, "hello", ...t1);  // [42, "hello", boolean]
+>z16 : Symbol(z16, Decl(genericRestParameters1.ts, 59, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>t1 : Symbol(t1, Decl(genericRestParameters1.ts, 8, 13))
+
+const z17 = f11(42, "hello", true, ...t0);  // [42, "hello", true]
+>z17 : Symbol(z17, Decl(genericRestParameters1.ts, 60, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>t0 : Symbol(t0, Decl(genericRestParameters1.ts, 9, 13))
+
+const z18 = f11(...ns, true);  // (string | number | true)[]
+>z18 : Symbol(z18, Decl(genericRestParameters1.ts, 61, 5))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>ns : Symbol(ns, Decl(genericRestParameters1.ts, 11, 13))
+
+function g11<U extends string[], V extends [number, number]>(u: U, v: V) {
+>g11 : Symbol(g11, Decl(genericRestParameters1.ts, 61, 29))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 63, 13))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 63, 32))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 63, 61))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 63, 13))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 63, 66))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 63, 32))
+
+    let x1 = f11(...u);  // U
+>x1 : Symbol(x1, Decl(genericRestParameters1.ts, 64, 7))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 63, 61))
+
+    let x2 = f11(...v);  // V
+>x2 : Symbol(x2, Decl(genericRestParameters1.ts, 65, 7))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 63, 66))
+
+    let x3 = f11(1, ...u);  // [1, ...string[]]
+>x3 : Symbol(x3, Decl(genericRestParameters1.ts, 66, 7))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 63, 61))
+
+    let x4 = f11(...u, ...v);  // (string | number)[]
+>x4 : Symbol(x4, Decl(genericRestParameters1.ts, 67, 7))
+>f11 : Symbol(f11, Decl(genericRestParameters1.ts, 49, 1))
+>u : Symbol(u, Decl(genericRestParameters1.ts, 63, 61))
+>v : Symbol(v, Decl(genericRestParameters1.ts, 63, 66))
+}
+
+function call<T extends unknown[], U>(f: (...args: T) => U, ...args: T) {
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 70, 14))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 70, 34))
+>f : Symbol(f, Decl(genericRestParameters1.ts, 70, 38))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 70, 42))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 70, 14))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 70, 34))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 70, 59))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 70, 14))
+
+    return f(...args);
+>f : Symbol(f, Decl(genericRestParameters1.ts, 70, 38))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 70, 59))
+}
+
+function callr<T extends unknown[], U>(args: T, f: (...args: T) => U) {
+>callr : Symbol(callr, Decl(genericRestParameters1.ts, 72, 1))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 74, 15))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 74, 35))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 74, 39))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 74, 15))
+>f : Symbol(f, Decl(genericRestParameters1.ts, 74, 47))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 74, 52))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 74, 15))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 74, 35))
+
+    return f(...args);
+>f : Symbol(f, Decl(genericRestParameters1.ts, 74, 47))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 74, 39))
+}
+
+declare function f15(a: string, b: number): string | number;
+>f15 : Symbol(f15, Decl(genericRestParameters1.ts, 76, 1))
+>a : Symbol(a, Decl(genericRestParameters1.ts, 78, 21))
+>b : Symbol(b, Decl(genericRestParameters1.ts, 78, 31))
+
+declare function f16<A, B>(a: A, b: B): A | B;
+>f16 : Symbol(f16, Decl(genericRestParameters1.ts, 78, 60))
+>A : Symbol(A, Decl(genericRestParameters1.ts, 79, 21))
+>B : Symbol(B, Decl(genericRestParameters1.ts, 79, 23))
+>a : Symbol(a, Decl(genericRestParameters1.ts, 79, 27))
+>A : Symbol(A, Decl(genericRestParameters1.ts, 79, 21))
+>b : Symbol(b, Decl(genericRestParameters1.ts, 79, 32))
+>B : Symbol(B, Decl(genericRestParameters1.ts, 79, 23))
+>A : Symbol(A, Decl(genericRestParameters1.ts, 79, 21))
+>B : Symbol(B, Decl(genericRestParameters1.ts, 79, 23))
+
+let x20 = call((x, y) => x + y, 10, 20);  // number
+>x20 : Symbol(x20, Decl(genericRestParameters1.ts, 81, 3))
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 81, 16))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 81, 18))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 81, 16))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 81, 18))
+
+let x21 = call((x, y) => x + y, 10, "hello");  // string
+>x21 : Symbol(x21, Decl(genericRestParameters1.ts, 82, 3))
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 82, 16))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 82, 18))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 82, 16))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 82, 18))
+
+let x22 = call(f15, "hello", 42);  // string | number
+>x22 : Symbol(x22, Decl(genericRestParameters1.ts, 83, 3))
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>f15 : Symbol(f15, Decl(genericRestParameters1.ts, 76, 1))
+
+let x23 = call(f16, "hello", 42);  // unknown
+>x23 : Symbol(x23, Decl(genericRestParameters1.ts, 84, 3))
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>f16 : Symbol(f16, Decl(genericRestParameters1.ts, 78, 60))
+
+let x24 = call<[string, number], string | number>(f16, "hello", 42);  // string | number
+>x24 : Symbol(x24, Decl(genericRestParameters1.ts, 85, 3))
+>call : Symbol(call, Decl(genericRestParameters1.ts, 68, 1))
+>f16 : Symbol(f16, Decl(genericRestParameters1.ts, 78, 60))
+
+let x30 = callr(sn, (x, y) => x + y);  // string
+>x30 : Symbol(x30, Decl(genericRestParameters1.ts, 87, 3))
+>callr : Symbol(callr, Decl(genericRestParameters1.ts, 72, 1))
+>sn : Symbol(sn, Decl(genericRestParameters1.ts, 12, 13))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 87, 21))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 87, 23))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 87, 21))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 87, 23))
+
+let x31 = callr(sn, f15);  // string | number
+>x31 : Symbol(x31, Decl(genericRestParameters1.ts, 88, 3))
+>callr : Symbol(callr, Decl(genericRestParameters1.ts, 72, 1))
+>sn : Symbol(sn, Decl(genericRestParameters1.ts, 12, 13))
+>f15 : Symbol(f15, Decl(genericRestParameters1.ts, 76, 1))
+
+let x32 = callr(sn, f16);  // string | number
+>x32 : Symbol(x32, Decl(genericRestParameters1.ts, 89, 3))
+>callr : Symbol(callr, Decl(genericRestParameters1.ts, 72, 1))
+>sn : Symbol(sn, Decl(genericRestParameters1.ts, 12, 13))
+>f16 : Symbol(f16, Decl(genericRestParameters1.ts, 78, 60))
+
+function bind<T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) {
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 91, 14))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 91, 16))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 91, 37))
+>f : Symbol(f, Decl(genericRestParameters1.ts, 91, 41))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 91, 45))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 91, 14))
+>rest : Symbol(rest, Decl(genericRestParameters1.ts, 91, 50))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 91, 16))
+>V : Symbol(V, Decl(genericRestParameters1.ts, 91, 37))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 91, 68))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 91, 14))
+
+    return (...rest: U) => f(x, ...rest);
+>rest : Symbol(rest, Decl(genericRestParameters1.ts, 92, 12))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 91, 16))
+>f : Symbol(f, Decl(genericRestParameters1.ts, 91, 41))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 91, 68))
+>rest : Symbol(rest, Decl(genericRestParameters1.ts, 92, 12))
+}
+
+declare const f20: (x: number, y: string, z: boolean) => string[];
+>f20 : Symbol(f20, Decl(genericRestParameters1.ts, 95, 13))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 95, 20))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 95, 30))
+>z : Symbol(z, Decl(genericRestParameters1.ts, 95, 41))
+
+const f21 = bind(f20, 42);  // (y: string, z: boolean) => string[]
+>f21 : Symbol(f21, Decl(genericRestParameters1.ts, 97, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>f20 : Symbol(f20, Decl(genericRestParameters1.ts, 95, 13))
+
+const f22 = bind(f21, "hello");  // (z: boolean) => string[]
+>f22 : Symbol(f22, Decl(genericRestParameters1.ts, 98, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>f21 : Symbol(f21, Decl(genericRestParameters1.ts, 97, 5))
+
+const f23 = bind(f22, true);  // () => string[]
+>f23 : Symbol(f23, Decl(genericRestParameters1.ts, 99, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>f22 : Symbol(f22, Decl(genericRestParameters1.ts, 98, 5))
+
+f20(42, "hello", true);
+>f20 : Symbol(f20, Decl(genericRestParameters1.ts, 95, 13))
+
+f21("hello", true);
+>f21 : Symbol(f21, Decl(genericRestParameters1.ts, 97, 5))
+
+f22(true);
+>f22 : Symbol(f22, Decl(genericRestParameters1.ts, 98, 5))
+
+f23();
+>f23 : Symbol(f23, Decl(genericRestParameters1.ts, 99, 5))
+
+declare const g20: (x: number, y?: string, z?: boolean) => string[];
+>g20 : Symbol(g20, Decl(genericRestParameters1.ts, 106, 13))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 106, 20))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 106, 30))
+>z : Symbol(z, Decl(genericRestParameters1.ts, 106, 42))
+
+const g21 = bind(g20, 42);  // (y: string, z: boolean) => string[]
+>g21 : Symbol(g21, Decl(genericRestParameters1.ts, 108, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>g20 : Symbol(g20, Decl(genericRestParameters1.ts, 106, 13))
+
+const g22 = bind(g21, "hello");  // (z: boolean) => string[]
+>g22 : Symbol(g22, Decl(genericRestParameters1.ts, 109, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>g21 : Symbol(g21, Decl(genericRestParameters1.ts, 108, 5))
+
+const g23 = bind(g22, true);  // () => string[]
+>g23 : Symbol(g23, Decl(genericRestParameters1.ts, 110, 5))
+>bind : Symbol(bind, Decl(genericRestParameters1.ts, 89, 25))
+>g22 : Symbol(g22, Decl(genericRestParameters1.ts, 109, 5))
+
+g20(42, "hello", true);
+>g20 : Symbol(g20, Decl(genericRestParameters1.ts, 106, 13))
+
+g20(42, "hello");
+>g20 : Symbol(g20, Decl(genericRestParameters1.ts, 106, 13))
+
+g20(42);
+>g20 : Symbol(g20, Decl(genericRestParameters1.ts, 106, 13))
+
+g21("hello", true);
+>g21 : Symbol(g21, Decl(genericRestParameters1.ts, 108, 5))
+
+g21("hello");
+>g21 : Symbol(g21, Decl(genericRestParameters1.ts, 108, 5))
+
+g21();
+>g21 : Symbol(g21, Decl(genericRestParameters1.ts, 108, 5))
+
+g22(true);
+>g22 : Symbol(g22, Decl(genericRestParameters1.ts, 109, 5))
+
+g22();
+>g22 : Symbol(g22, Decl(genericRestParameters1.ts, 109, 5))
+
+g23();
+>g23 : Symbol(g23, Decl(genericRestParameters1.ts, 110, 5))
+
+declare function f30<T, U extends ((x: T) => any)[]>(x: T, ...args: U): U;
+>f30 : Symbol(f30, Decl(genericRestParameters1.ts, 120, 6))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 122, 21))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 122, 23))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 122, 36))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 122, 21))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 122, 53))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 122, 21))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 122, 58))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 122, 23))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 122, 23))
+
+const c30 = f30(42, x => "" + x, x => x + 1);  // [(x: number) => string, (x: number) => number]
+>c30 : Symbol(c30, Decl(genericRestParameters1.ts, 124, 5))
+>f30 : Symbol(f30, Decl(genericRestParameters1.ts, 120, 6))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 124, 19))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 124, 19))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 124, 32))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 124, 32))
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 126, 16))
+>Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 126, 16))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 126, 50))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 126, 64), Decl(genericRestParameters1.ts, 126, 97))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 126, 83))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 126, 64), Decl(genericRestParameters1.ts, 126, 97))
+>U : Symbol(U, Decl(genericRestParameters1.ts, 126, 64), Decl(genericRestParameters1.ts, 126, 97))
+
+type T01 = Parameters<(x: number, y: string, z: boolean) => void>;
+>T01 : Symbol(T01, Decl(genericRestParameters1.ts, 126, 121))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 128, 23))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 128, 33))
+>z : Symbol(z, Decl(genericRestParameters1.ts, 128, 44))
+
+type T02 = Parameters<(...args: [number, string, boolean]) => void>;
+>T02 : Symbol(T02, Decl(genericRestParameters1.ts, 128, 66))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 129, 23))
+
+type T03 = Parameters<new (x: number, y: string, z: boolean) => void>;
+>T03 : Symbol(T03, Decl(genericRestParameters1.ts, 129, 68))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>x : Symbol(x, Decl(genericRestParameters1.ts, 130, 27))
+>y : Symbol(y, Decl(genericRestParameters1.ts, 130, 37))
+>z : Symbol(z, Decl(genericRestParameters1.ts, 130, 48))
+
+type T04 = Parameters<new (...args: [number, string, boolean]) => void>;
+>T04 : Symbol(T04, Decl(genericRestParameters1.ts, 130, 70))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 131, 27))
+
+type T05<T> = Parameters<(...args: T[]) => void>;
+>T05 : Symbol(T05, Decl(genericRestParameters1.ts, 131, 72))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 132, 9))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 132, 26))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 132, 9))
+
+type T06<T> = Parameters<new (...args: []) => void>;
+>T06 : Symbol(T06, Decl(genericRestParameters1.ts, 132, 49))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 133, 9))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 133, 30))
+
+type T07<T extends any[]> = Parameters<(...args: T) => void>;
+>T07 : Symbol(T07, Decl(genericRestParameters1.ts, 133, 52))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 134, 9))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 134, 40))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 134, 9))
+
+type T08<T extends any[]> = Parameters<new (...args: T) => void>;
+>T08 : Symbol(T08, Decl(genericRestParameters1.ts, 134, 61))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 135, 9))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>args : Symbol(args, Decl(genericRestParameters1.ts, 135, 44))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 135, 9))
+
+type T09 = Parameters<Function>;
+>T09 : Symbol(T09, Decl(genericRestParameters1.ts, 135, 65))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters1.ts, 124, 45))
+>Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+type Record1 = {
+>Record1 : Symbol(Record1, Decl(genericRestParameters1.ts, 136, 32))
+
+  move: [number, 'left' | 'right'];
+>move : Symbol(move, Decl(genericRestParameters1.ts, 138, 16))
+
+  jump: [number, 'up' | 'down'];
+>jump : Symbol(jump, Decl(genericRestParameters1.ts, 139, 35))
+
+  stop: string;
+>stop : Symbol(stop, Decl(genericRestParameters1.ts, 140, 32))
+
+  done: [];
+>done : Symbol(done, Decl(genericRestParameters1.ts, 141, 15))
+}
+
+type EventType<T> = {
+>EventType : Symbol(EventType, Decl(genericRestParameters1.ts, 143, 1))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+
+  emit<K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]): void; 
+>emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+>K : Symbol(K, Decl(genericRestParameters1.ts, 146, 7))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+>e : Symbol(e, Decl(genericRestParameters1.ts, 146, 36))
+>K : Symbol(K, Decl(genericRestParameters1.ts, 146, 7))
+>payload : Symbol(payload, Decl(genericRestParameters1.ts, 146, 41))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+>K : Symbol(K, Decl(genericRestParameters1.ts, 146, 7))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+>K : Symbol(K, Decl(genericRestParameters1.ts, 146, 7))
+>T : Symbol(T, Decl(genericRestParameters1.ts, 145, 15))
+>K : Symbol(K, Decl(genericRestParameters1.ts, 146, 7))
+}
+
+declare var events: EventType<Record1>;
+>events : Symbol(events, Decl(genericRestParameters1.ts, 149, 11))
+>EventType : Symbol(EventType, Decl(genericRestParameters1.ts, 143, 1))
+>Record1 : Symbol(Record1, Decl(genericRestParameters1.ts, 136, 32))
+
+events.emit('move', 10, 'left');
+>events.emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+>events : Symbol(events, Decl(genericRestParameters1.ts, 149, 11))
+>emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+
+events.emit('jump', 20, 'up');
+>events.emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+>events : Symbol(events, Decl(genericRestParameters1.ts, 149, 11))
+>emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+
+events.emit('stop', 'Bye!');
+>events.emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+>events : Symbol(events, Decl(genericRestParameters1.ts, 149, 11))
+>emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+
+events.emit('done');
+>events.emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+>events : Symbol(events, Decl(genericRestParameters1.ts, 149, 11))
+>emit : Symbol(emit, Decl(genericRestParameters1.ts, 145, 21))
+

tests/baselines/reference/genericRestParameters1.types

@@ -0,0 +1,851 @@
+=== tests/cases/conformance/types/rest/genericRestParameters1.ts ===
+declare let f1: (...x: [number, string, boolean]) => void;
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>x : [number, string, boolean]
+
+declare let f2: (x0: number, x1: string, x2: boolean) => void;
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>x0 : number
+>x1 : string
+>x2 : boolean
+
+f1 = f2;
+>f1 = f2 : (x0: number, x1: string, x2: boolean) => void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+
+f2 = f1;
+>f2 = f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+
+declare const t3: [number, string, boolean];
+>t3 : [number, string, boolean]
+
+declare const t2: [string, boolean];
+>t2 : [string, boolean]
+
+declare const t1: [boolean];
+>t1 : [boolean]
+
+declare const t0: [];
+>t0 : []
+
+declare const ns: [number, string];
+>ns : [number, string]
+
+declare const sn: [string, number];
+>sn : [string, number]
+
+f1(42, "hello", true);
+>f1(42, "hello", true) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f1(t3[0], t3[1], t3[2]);
+>f1(t3[0], t3[1], t3[2]) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>t3[0] : number
+>t3 : [number, string, boolean]
+>0 : 0
+>t3[1] : string
+>t3 : [number, string, boolean]
+>1 : 1
+>t3[2] : boolean
+>t3 : [number, string, boolean]
+>2 : 2
+
+f1(...t3);
+>f1(...t3) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>...t3 : string | number | boolean
+>t3 : [number, string, boolean]
+
+f1(42, ...t2);
+>f1(42, ...t2) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, boolean]
+
+f1(42, "hello", ...t1);
+>f1(42, "hello", ...t1) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>...t1 : boolean
+>t1 : [boolean]
+
+f1(42, "hello", true, ...t0);
+>f1(42, "hello", true, ...t0) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t0 : never
+>t0 : []
+
+f1(ns[0], ns[1], true);
+>f1(ns[0], ns[1], true) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>ns[0] : number
+>ns : [number, string]
+>0 : 0
+>ns[1] : string
+>ns : [number, string]
+>1 : 1
+>true : true
+
+f1(...ns, true);  // Error, tuple spread only expanded when last
+>f1(...ns, true) : void
+>f1 : (x_0: number, x_1: string, x_2: boolean) => void
+>...ns : string | number
+>ns : [number, string]
+>true : true
+
+f2(42, "hello", true);
+>f2(42, "hello", true) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f2(t3[0], t3[1], t3[2]);
+>f2(t3[0], t3[1], t3[2]) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>t3[0] : number
+>t3 : [number, string, boolean]
+>0 : 0
+>t3[1] : string
+>t3 : [number, string, boolean]
+>1 : 1
+>t3[2] : boolean
+>t3 : [number, string, boolean]
+>2 : 2
+
+f2(...t3);
+>f2(...t3) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>...t3 : string | number | boolean
+>t3 : [number, string, boolean]
+
+f2(42, ...t2);
+>f2(42, ...t2) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, boolean]
+
+f2(42, "hello", ...t1);
+>f2(42, "hello", ...t1) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>...t1 : boolean
+>t1 : [boolean]
+
+f2(42, "hello", true, ...t0);
+>f2(42, "hello", true, ...t0) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t0 : never
+>t0 : []
+
+f2(ns[0], ns[1], true);
+>f2(ns[0], ns[1], true) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>ns[0] : number
+>ns : [number, string]
+>0 : 0
+>ns[1] : string
+>ns : [number, string]
+>1 : 1
+>true : true
+
+f2(...ns, true);  // Error, tuple spread only expanded when last
+>f2(...ns, true) : void
+>f2 : (x0: number, x1: string, x2: boolean) => void
+>...ns : string | number
+>ns : [number, string]
+>true : true
+
+declare function f10<T extends unknown[]>(...args: T): T;
+>f10 : <T extends unknown[]>(...args: T) => T
+>T : T
+>args : T
+>T : T
+>T : T
+
+const x10 = f10(42, "hello", true);  // [number, string, boolean]
+>x10 : [number, string, boolean]
+>f10(42, "hello", true) : [number, string, boolean]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+const x11 = f10(42, "hello");  // [number, string]
+>x11 : [number, string]
+>f10(42, "hello") : [number, string]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+
+const x12 = f10(42);  // [number]
+>x12 : [number]
+>f10(42) : [number]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+
+const x13 = f10();  // []
+>x13 : []
+>f10() : []
+>f10 : <T extends unknown[]>(...args: T) => T
+
+const x14 = f10(...t3);  // [number, string, boolean]
+>x14 : [number, string, boolean]
+>f10(...t3) : [number, string, boolean]
+>f10 : <T extends unknown[]>(...args: T) => T
+>...t3 : string | number | boolean
+>t3 : [number, string, boolean]
+
+const x15 = f10(42, ...t2);  // [number, string, boolean]
+>x15 : [number, string, boolean]
+>f10(42, ...t2) : [number, string, boolean]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, boolean]
+
+const x16 = f10(42, "hello", ...t1);  // [number, string, boolean]
+>x16 : [number, string, boolean]
+>f10(42, "hello", ...t1) : [number, string, boolean]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>...t1 : boolean
+>t1 : [boolean]
+
+const x17 = f10(42, "hello", true, ...t0);  // [number, string, boolean]
+>x17 : [number, string, boolean]
+>f10(42, "hello", true, ...t0) : [number, string, boolean]
+>f10 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t0 : never
+>t0 : []
+
+const x18 = f10(...ns, true);  // (string | number | boolean)[]
+>x18 : (string | number | boolean)[]
+>f10(...ns, true) : (string | number | boolean)[]
+>f10 : <T extends unknown[]>(...args: T) => T
+>...ns : string | number
+>ns : [number, string]
+>true : true
+
+function g10<U extends string[], V extends [number, number]>(u: U, v: V) {
+>g10 : <U extends string[], V extends [number, number]>(u: U, v: V) => void
+>U : U
+>V : V
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let x1 = f10(...u);  // U
+>x1 : U
+>f10(...u) : U
+>f10 : <T extends unknown[]>(...args: T) => T
+>...u : string
+>u : U
+
+    let x2 = f10(...v);  // V
+>x2 : V
+>f10(...v) : V
+>f10 : <T extends unknown[]>(...args: T) => T
+>...v : number
+>v : V
+
+    let x3 = f10(1, ...u);  // [number, ...string[]]
+>x3 : [number, ...string[]]
+>f10(1, ...u) : [number, ...string[]]
+>f10 : <T extends unknown[]>(...args: T) => T
+>1 : 1
+>...u : string
+>u : U
+
+    let x4 = f10(...u, ...v);  // (string | number)[]
+>x4 : (string | number)[]
+>f10(...u, ...v) : (string | number)[]
+>f10 : <T extends unknown[]>(...args: T) => T
+>...u : string
+>u : U
+>...v : number
+>v : V
+}
+
+declare function f11<T extends (string | number | boolean)[]>(...args: T): T;
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>T : T
+>args : T
+>T : T
+>T : T
+
+const z10 = f11(42, "hello", true);  // [42, "hello", true]
+>z10 : [42, "hello", true]
+>f11(42, "hello", true) : [42, "hello", true]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+const z11 = f11(42, "hello");  // [42, "hello"]
+>z11 : [42, "hello"]
+>f11(42, "hello") : [42, "hello"]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+
+const z12 = f11(42);  // [42]
+>z12 : [42]
+>f11(42) : [42]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+
+const z13 = f11();  // []
+>z13 : []
+>f11() : []
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+
+const z14 = f11(...t3);  // [number, string, boolean]
+>z14 : [number, string, boolean]
+>f11(...t3) : [number, string, boolean]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>...t3 : string | number | boolean
+>t3 : [number, string, boolean]
+
+const z15 = f11(42, ...t2);  // [42, string, boolean]
+>z15 : [42, string, boolean]
+>f11(42, ...t2) : [42, string, boolean]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, boolean]
+
+const z16 = f11(42, "hello", ...t1);  // [42, "hello", boolean]
+>z16 : [42, "hello", boolean]
+>f11(42, "hello", ...t1) : [42, "hello", boolean]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>...t1 : boolean
+>t1 : [boolean]
+
+const z17 = f11(42, "hello", true, ...t0);  // [42, "hello", true]
+>z17 : [42, "hello", true]
+>f11(42, "hello", true, ...t0) : [42, "hello", true]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t0 : never
+>t0 : []
+
+const z18 = f11(...ns, true);  // (string | number | true)[]
+>z18 : (string | number | true)[]
+>f11(...ns, true) : (string | number | true)[]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>...ns : string | number
+>ns : [number, string]
+>true : true
+
+function g11<U extends string[], V extends [number, number]>(u: U, v: V) {
+>g11 : <U extends string[], V extends [number, number]>(u: U, v: V) => void
+>U : U
+>V : V
+>u : U
+>U : U
+>v : V
+>V : V
+
+    let x1 = f11(...u);  // U
+>x1 : U
+>f11(...u) : U
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>...u : string
+>u : U
+
+    let x2 = f11(...v);  // V
+>x2 : V
+>f11(...v) : V
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>...v : number
+>v : V
+
+    let x3 = f11(1, ...u);  // [1, ...string[]]
+>x3 : [1, ...string[]]
+>f11(1, ...u) : [1, ...string[]]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>1 : 1
+>...u : string
+>u : U
+
+    let x4 = f11(...u, ...v);  // (string | number)[]
+>x4 : (string | number)[]
+>f11(...u, ...v) : (string | number)[]
+>f11 : <T extends (string | number | boolean)[]>(...args: T) => T
+>...u : string
+>u : U
+>...v : number
+>v : V
+}
+
+function call<T extends unknown[], U>(f: (...args: T) => U, ...args: T) {
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>T : T
+>U : U
+>f : (...args: T) => U
+>args : T
+>T : T
+>U : U
+>args : T
+>T : T
+
+    return f(...args);
+>f(...args) : U
+>f : (...args: T) => U
+>...args : unknown
+>args : T
+}
+
+function callr<T extends unknown[], U>(args: T, f: (...args: T) => U) {
+>callr : <T extends unknown[], U>(args: T, f: (...args: T) => U) => U
+>T : T
+>U : U
+>args : T
+>T : T
+>f : (...args: T) => U
+>args : T
+>T : T
+>U : U
+
+    return f(...args);
+>f(...args) : U
+>f : (...args: T) => U
+>...args : unknown
+>args : T
+}
+
+declare function f15(a: string, b: number): string | number;
+>f15 : (a: string, b: number) => string | number
+>a : string
+>b : number
+
+declare function f16<A, B>(a: A, b: B): A | B;
+>f16 : <A, B>(a: A, b: B) => A | B
+>A : A
+>B : B
+>a : A
+>A : A
+>b : B
+>B : B
+>A : A
+>B : B
+
+let x20 = call((x, y) => x + y, 10, 20);  // number
+>x20 : number
+>call((x, y) => x + y, 10, 20) : number
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>(x, y) => x + y : (x: number, y: number) => number
+>x : number
+>y : number
+>x + y : number
+>x : number
+>y : number
+>10 : 10
+>20 : 20
+
+let x21 = call((x, y) => x + y, 10, "hello");  // string
+>x21 : string
+>call((x, y) => x + y, 10, "hello") : string
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>(x, y) => x + y : (x: number, y: string) => string
+>x : number
+>y : string
+>x + y : string
+>x : number
+>y : string
+>10 : 10
+>"hello" : "hello"
+
+let x22 = call(f15, "hello", 42);  // string | number
+>x22 : string | number
+>call(f15, "hello", 42) : string | number
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>f15 : (a: string, b: number) => string | number
+>"hello" : "hello"
+>42 : 42
+
+let x23 = call(f16, "hello", 42);  // unknown
+>x23 : unknown
+>call(f16, "hello", 42) : unknown
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>f16 : <A, B>(a: A, b: B) => A | B
+>"hello" : "hello"
+>42 : 42
+
+let x24 = call<[string, number], string | number>(f16, "hello", 42);  // string | number
+>x24 : string | number
+>call<[string, number], string | number>(f16, "hello", 42) : string | number
+>call : <T extends unknown[], U>(f: (...args: T) => U, ...args: T) => U
+>f16 : <A, B>(a: A, b: B) => A | B
+>"hello" : "hello"
+>42 : 42
+
+let x30 = callr(sn, (x, y) => x + y);  // string
+>x30 : string
+>callr(sn, (x, y) => x + y) : string
+>callr : <T extends unknown[], U>(args: T, f: (...args: T) => U) => U
+>sn : [string, number]
+>(x, y) => x + y : (x: string, y: number) => string
+>x : string
+>y : number
+>x + y : string
+>x : string
+>y : number
+
+let x31 = callr(sn, f15);  // string | number
+>x31 : string | number
+>callr(sn, f15) : string | number
+>callr : <T extends unknown[], U>(args: T, f: (...args: T) => U) => U
+>sn : [string, number]
+>f15 : (a: string, b: number) => string | number
+
+let x32 = callr(sn, f16);  // string | number
+>x32 : string | number
+>callr(sn, f16) : string | number
+>callr : <T extends unknown[], U>(args: T, f: (...args: T) => U) => U
+>sn : [string, number]
+>f16 : <A, B>(a: A, b: B) => A | B
+
+function bind<T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) {
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>T : T
+>U : U
+>V : V
+>f : (x: T, ...rest: U) => V
+>x : T
+>T : T
+>rest : U
+>U : U
+>V : V
+>x : T
+>T : T
+
+    return (...rest: U) => f(x, ...rest);
+>(...rest: U) => f(x, ...rest) : (...rest: U) => V
+>rest : U
+>U : U
+>f(x, ...rest) : V
+>f : (x: T, ...rest: U) => V
+>x : T
+>...rest : unknown
+>rest : U
+}
+
+declare const f20: (x: number, y: string, z: boolean) => string[];
+>f20 : (x: number, y: string, z: boolean) => string[]
+>x : number
+>y : string
+>z : boolean
+
+const f21 = bind(f20, 42);  // (y: string, z: boolean) => string[]
+>f21 : (y: string, z: boolean) => string[]
+>bind(f20, 42) : (y: string, z: boolean) => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>f20 : (x: number, y: string, z: boolean) => string[]
+>42 : 42
+
+const f22 = bind(f21, "hello");  // (z: boolean) => string[]
+>f22 : (z: boolean) => string[]
+>bind(f21, "hello") : (z: boolean) => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>f21 : (y: string, z: boolean) => string[]
+>"hello" : "hello"
+
+const f23 = bind(f22, true);  // () => string[]
+>f23 : () => string[]
+>bind(f22, true) : () => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>f22 : (z: boolean) => string[]
+>true : true
+
+f20(42, "hello", true);
+>f20(42, "hello", true) : string[]
+>f20 : (x: number, y: string, z: boolean) => string[]
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f21("hello", true);
+>f21("hello", true) : string[]
+>f21 : (y: string, z: boolean) => string[]
+>"hello" : "hello"
+>true : true
+
+f22(true);
+>f22(true) : string[]
+>f22 : (z: boolean) => string[]
+>true : true
+
+f23();
+>f23() : string[]
+>f23 : () => string[]
+
+declare const g20: (x: number, y?: string, z?: boolean) => string[];
+>g20 : (x: number, y?: string | undefined, z?: boolean | undefined) => string[]
+>x : number
+>y : string | undefined
+>z : boolean | undefined
+
+const g21 = bind(g20, 42);  // (y: string, z: boolean) => string[]
+>g21 : (y?: string | undefined, z?: boolean | undefined) => string[]
+>bind(g20, 42) : (y?: string | undefined, z?: boolean | undefined) => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>g20 : (x: number, y?: string | undefined, z?: boolean | undefined) => string[]
+>42 : 42
+
+const g22 = bind(g21, "hello");  // (z: boolean) => string[]
+>g22 : (z?: boolean | undefined) => string[]
+>bind(g21, "hello") : (z?: boolean | undefined) => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>g21 : (y?: string | undefined, z?: boolean | undefined) => string[]
+>"hello" : "hello"
+
+const g23 = bind(g22, true);  // () => string[]
+>g23 : () => string[]
+>bind(g22, true) : () => string[]
+>bind : <T, U extends unknown[], V>(f: (x: T, ...rest: U) => V, x: T) => (...rest: U) => V
+>g22 : (z?: boolean | undefined) => string[]
+>true : true
+
+g20(42, "hello", true);
+>g20(42, "hello", true) : string[]
+>g20 : (x: number, y?: string | undefined, z?: boolean | undefined) => string[]
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+g20(42, "hello");
+>g20(42, "hello") : string[]
+>g20 : (x: number, y?: string | undefined, z?: boolean | undefined) => string[]
+>42 : 42
+>"hello" : "hello"
+
+g20(42);
+>g20(42) : string[]
+>g20 : (x: number, y?: string | undefined, z?: boolean | undefined) => string[]
+>42 : 42
+
+g21("hello", true);
+>g21("hello", true) : string[]
+>g21 : (y?: string | undefined, z?: boolean | undefined) => string[]
+>"hello" : "hello"
+>true : true
+
+g21("hello");
+>g21("hello") : string[]
+>g21 : (y?: string | undefined, z?: boolean | undefined) => string[]
+>"hello" : "hello"
+
+g21();
+>g21() : string[]
+>g21 : (y?: string | undefined, z?: boolean | undefined) => string[]
+
+g22(true);
+>g22(true) : string[]
+>g22 : (z?: boolean | undefined) => string[]
+>true : true
+
+g22();
+>g22() : string[]
+>g22 : (z?: boolean | undefined) => string[]
+
+g23();
+>g23() : string[]
+>g23 : () => string[]
+
+declare function f30<T, U extends ((x: T) => any)[]>(x: T, ...args: U): U;
+>f30 : <T, U extends ((x: T) => any)[]>(x: T, ...args: U) => U
+>T : T
+>U : U
+>x : T
+>T : T
+>x : T
+>T : T
+>args : U
+>U : U
+>U : U
+
+const c30 = f30(42, x => "" + x, x => x + 1);  // [(x: number) => string, (x: number) => number]
+>c30 : [(x: number) => string, (x: number) => number]
+>f30(42, x => "" + x, x => x + 1) : [(x: number) => string, (x: number) => number]
+>f30 : <T, U extends ((x: T) => any)[]>(x: T, ...args: U) => U
+>42 : 42
+>x => "" + x : (x: number) => string
+>x : number
+>"" + x : string
+>"" : ""
+>x : number
+>x => x + 1 : (x: number) => number
+>x : number
+>x + 1 : number
+>x : number
+>1 : 1
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+>Parameters : Parameters<T>
+>T : T
+>Function : Function
+>T : T
+>args : U
+>U : U
+>args : U
+>U : U
+>U : U
+
+type T01 = Parameters<(x: number, y: string, z: boolean) => void>;
+>T01 : [number, string, boolean]
+>Parameters : Parameters<T>
+>x : number
+>y : string
+>z : boolean
+
+type T02 = Parameters<(...args: [number, string, boolean]) => void>;
+>T02 : [number, string, boolean]
+>Parameters : Parameters<T>
+>args : [number, string, boolean]
+
+type T03 = Parameters<new (x: number, y: string, z: boolean) => void>;
+>T03 : [number, string, boolean]
+>Parameters : Parameters<T>
+>x : number
+>y : string
+>z : boolean
+
+type T04 = Parameters<new (...args: [number, string, boolean]) => void>;
+>T04 : [number, string, boolean]
+>Parameters : Parameters<T>
+>args : [number, string, boolean]
+
+type T05<T> = Parameters<(...args: T[]) => void>;
+>T05 : T[]
+>T : T
+>Parameters : Parameters<T>
+>args : T[]
+>T : T
+
+type T06<T> = Parameters<new (...args: []) => void>;
+>T06 : []
+>T : T
+>Parameters : Parameters<T>
+>args : []
+
+type T07<T extends any[]> = Parameters<(...args: T) => void>;
+>T07 : T
+>T : T
+>Parameters : Parameters<T>
+>args : T
+>T : T
+
+type T08<T extends any[]> = Parameters<new (...args: T) => void>;
+>T08 : T
+>T : T
+>Parameters : Parameters<T>
+>args : T
+>T : T
+
+type T09 = Parameters<Function>;
+>T09 : any[]
+>Parameters : Parameters<T>
+>Function : Function
+
+type Record1 = {
+>Record1 : Record1
+
+  move: [number, 'left' | 'right'];
+>move : [number, "left" | "right"]
+
+  jump: [number, 'up' | 'down'];
+>jump : [number, "up" | "down"]
+
+  stop: string;
+>stop : string
+
+  done: [];
+>done : []
+}
+
+type EventType<T> = {
+>EventType : EventType<T>
+>T : T
+
+  emit<K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]): void; 
+>emit : <K extends keyof T = keyof T>(e: K, ...payload: T[K] extends any[] ? T[K] : [T[K]]) => void
+>K : K
+>T : T
+>T : T
+>e : K
+>K : K
+>payload : T[K] extends any[] ? T[K] : [T[K]]
+>T : T
+>K : K
+>T : T
+>K : K
+>T : T
+>K : K
+}
+
+declare var events: EventType<Record1>;
+>events : EventType<Record1>
+>EventType : EventType<T>
+>Record1 : Record1
+
+events.emit('move', 10, 'left');
+>events.emit('move', 10, 'left') : void
+>events.emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>events : EventType<Record1>
+>emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>'move' : "move"
+>10 : 10
+>'left' : "left"
+
+events.emit('jump', 20, 'up');
+>events.emit('jump', 20, 'up') : void
+>events.emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>events : EventType<Record1>
+>emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>'jump' : "jump"
+>20 : 20
+>'up' : "up"
+
+events.emit('stop', 'Bye!');
+>events.emit('stop', 'Bye!') : void
+>events.emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>events : EventType<Record1>
+>emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>'stop' : "stop"
+>'Bye!' : "Bye!"
+
+events.emit('done');
+>events.emit('done') : void
+>events.emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>events : EventType<Record1>
+>emit : <K extends "move" | "jump" | "stop" | "done" = "move" | "jump" | "stop" | "done">(e: K, ...payload: Record1[K] extends any[] ? Record1[K] : [Record1[K]]) => void
+>'done' : "done"
+

tests/baselines/reference/genericRestParameters2.js

@@ -0,0 +1,158 @@
+//// [genericRestParameters2.ts]
+declare const t1: [number, string, ...boolean[]];
+declare const t2: [string, ...boolean[]];
+declare const t3: [...boolean[]];
+declare const t4: [];
+
+declare let f00: (...x: [number, string, boolean]) => void;
+declare let f01: (a: number, ...x: [string, boolean]) => void;
+declare let f02: (a: number, b: string, ...x: [boolean]) => void;
+declare let f03: (a: number, b: string, c: boolean) => void;
+declare let f04: (a: number, b: string, c: boolean, ...x: []) => void;
+
+declare let f10: (...x: [number, string, ...boolean[]]) => void;
+declare let f11: (a: number, ...x: [string, ...boolean[]]) => void;
+declare let f12: (a: number, b: string, ...x: [...boolean[]]) => void;
+declare let f13: (a: number, b: string, ...c: boolean[]) => void;
+
+declare const ns: [number, string];
+declare const sn: [string, number];
+
+f10(42, "hello");
+f10(42, "hello", true);
+f10(42, "hello", true, false);
+f10(t1[0], t1[1], t1[2], t1[3]);
+f10(...t1);
+f10(42, ...t2);
+f10(42, "hello", ...t3);
+f10(42, "hello", true, ...t4);
+f10(42, "hello", true, ...t4, false, ...t3);
+
+f11(42, "hello");
+f11(42, "hello", true);
+f11(42, "hello", true, false);
+f11(t1[0], t1[1], t1[2], t1[3]);
+f11(...t1);
+f11(42, ...t2);
+f11(42, "hello", ...t3);
+f11(42, "hello", true, ...t4);
+f11(42, "hello", true, ...t4, false, ...t3);
+
+f12(42, "hello");
+f12(42, "hello", true);
+f12(42, "hello", true, false);
+f12(t1[0], t1[1], t1[2], t1[3]);
+f12(...t1);
+f12(42, ...t2);
+f12(42, "hello", ...t3);
+f12(42, "hello", true, ...t4);
+f12(42, "hello", true, ...t4, false, ...t3);
+
+f13(42, "hello");
+f13(42, "hello", true);
+f13(42, "hello", true, false);
+f13(t1[0], t1[1], t1[2], t1[3]);
+f13(...t1);
+f13(42, ...t2);
+f13(42, "hello", ...t3);
+f13(42, "hello", true, ...t4);
+f13(42, "hello", true, ...t4, false, ...t3);
+
+declare const f20: <T extends unknown[]>(...args: T) => T;
+
+f20(...t1);
+f20(42, ...t2);
+f20(42, "hello", ...t3);
+f20(42, "hello", ...t2, true);
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+
+type T01 = Parameters<(x: number, y: string, ...z: boolean[]) => void>;
+type T02 = Parameters<(...args: [number, string, ...boolean[]]) => void>;
+type T03 = Parameters<new (x: number, y: string, ...z: boolean[]) => void>;
+type T04 = Parameters<new (...args: [number, string, ...boolean[]]) => void>;
+type T05<T extends any[]> = Parameters<(x: string, ...args: T) => void>;
+type T06 = T05<[number, ...boolean[]]>;
+
+type P1<T extends Function> = T extends (head: infer A, ...tail: infer B) => any ? { head: A, tail: B } : any[];
+
+type T10 = P1<(x: number, y: string, ...z: boolean[]) => void>;
+type T11 = P1<(...z: number[]) => void>;
+type T12 = P1<(x: number, y: number) => void>;
+
+
+//// [genericRestParameters2.js]
+"use strict";
+f10(42, "hello");
+f10(42, "hello", true);
+f10(42, "hello", true, false);
+f10(t1[0], t1[1], t1[2], t1[3]);
+f10.apply(void 0, t1);
+f10.apply(void 0, [42].concat(t2));
+f10.apply(void 0, [42, "hello"].concat(t3));
+f10.apply(void 0, [42, "hello", true].concat(t4));
+f10.apply(void 0, [42, "hello", true].concat(t4, [false], t3));
+f11(42, "hello");
+f11(42, "hello", true);
+f11(42, "hello", true, false);
+f11(t1[0], t1[1], t1[2], t1[3]);
+f11.apply(void 0, t1);
+f11.apply(void 0, [42].concat(t2));
+f11.apply(void 0, [42, "hello"].concat(t3));
+f11.apply(void 0, [42, "hello", true].concat(t4));
+f11.apply(void 0, [42, "hello", true].concat(t4, [false], t3));
+f12(42, "hello");
+f12(42, "hello", true);
+f12(42, "hello", true, false);
+f12(t1[0], t1[1], t1[2], t1[3]);
+f12.apply(void 0, t1);
+f12.apply(void 0, [42].concat(t2));
+f12.apply(void 0, [42, "hello"].concat(t3));
+f12.apply(void 0, [42, "hello", true].concat(t4));
+f12.apply(void 0, [42, "hello", true].concat(t4, [false], t3));
+f13(42, "hello");
+f13(42, "hello", true);
+f13(42, "hello", true, false);
+f13(t1[0], t1[1], t1[2], t1[3]);
+f13.apply(void 0, t1);
+f13.apply(void 0, [42].concat(t2));
+f13.apply(void 0, [42, "hello"].concat(t3));
+f13.apply(void 0, [42, "hello", true].concat(t4));
+f13.apply(void 0, [42, "hello", true].concat(t4, [false], t3));
+f20.apply(void 0, t1);
+f20.apply(void 0, [42].concat(t2));
+f20.apply(void 0, [42, "hello"].concat(t3));
+f20.apply(void 0, [42, "hello"].concat(t2, [true]));
+
+
+//// [genericRestParameters2.d.ts]
+declare const t1: [number, string, ...boolean[]];
+declare const t2: [string, ...boolean[]];
+declare const t3: [...boolean[]];
+declare const t4: [];
+declare let f00: (...x: [number, string, boolean]) => void;
+declare let f01: (a: number, ...x: [string, boolean]) => void;
+declare let f02: (a: number, b: string, ...x: [boolean]) => void;
+declare let f03: (a: number, b: string, c: boolean) => void;
+declare let f04: (a: number, b: string, c: boolean, ...x: []) => void;
+declare let f10: (...x: [number, string, ...boolean[]]) => void;
+declare let f11: (a: number, ...x: [string, ...boolean[]]) => void;
+declare let f12: (a: number, b: string, ...x: [...boolean[]]) => void;
+declare let f13: (a: number, b: string, ...c: boolean[]) => void;
+declare const ns: [number, string];
+declare const sn: [string, number];
+declare const f20: <T extends unknown[]>(...args: T) => T;
+declare type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new (...args: infer U) => any) ? U : any[];
+declare type T01 = Parameters<(x: number, y: string, ...z: boolean[]) => void>;
+declare type T02 = Parameters<(...args: [number, string, ...boolean[]]) => void>;
+declare type T03 = Parameters<new (x: number, y: string, ...z: boolean[]) => void>;
+declare type T04 = Parameters<new (...args: [number, string, ...boolean[]]) => void>;
+declare type T05<T extends any[]> = Parameters<(x: string, ...args: T) => void>;
+declare type T06 = T05<[number, ...boolean[]]>;
+declare type P1<T extends Function> = T extends (head: infer A, ...tail: infer B) => any ? {
+    head: A;
+    tail: B;
+} : any[];
+declare type T10 = P1<(x: number, y: string, ...z: boolean[]) => void>;
+declare type T11 = P1<(...z: number[]) => void>;
+declare type T12 = P1<(x: number, y: number) => void>;

tests/baselines/reference/genericRestParameters2.symbols

@@ -0,0 +1,326 @@
+=== tests/cases/conformance/types/rest/genericRestParameters2.ts ===
+declare const t1: [number, string, ...boolean[]];
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+declare const t2: [string, ...boolean[]];
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+declare const t3: [...boolean[]];
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+declare const t4: [];
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+
+declare let f00: (...x: [number, string, boolean]) => void;
+>f00 : Symbol(f00, Decl(genericRestParameters2.ts, 5, 11))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 5, 18))
+
+declare let f01: (a: number, ...x: [string, boolean]) => void;
+>f01 : Symbol(f01, Decl(genericRestParameters2.ts, 6, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 6, 18))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 6, 28))
+
+declare let f02: (a: number, b: string, ...x: [boolean]) => void;
+>f02 : Symbol(f02, Decl(genericRestParameters2.ts, 7, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 7, 18))
+>b : Symbol(b, Decl(genericRestParameters2.ts, 7, 28))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 7, 39))
+
+declare let f03: (a: number, b: string, c: boolean) => void;
+>f03 : Symbol(f03, Decl(genericRestParameters2.ts, 8, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 8, 18))
+>b : Symbol(b, Decl(genericRestParameters2.ts, 8, 28))
+>c : Symbol(c, Decl(genericRestParameters2.ts, 8, 39))
+
+declare let f04: (a: number, b: string, c: boolean, ...x: []) => void;
+>f04 : Symbol(f04, Decl(genericRestParameters2.ts, 9, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 9, 18))
+>b : Symbol(b, Decl(genericRestParameters2.ts, 9, 28))
+>c : Symbol(c, Decl(genericRestParameters2.ts, 9, 39))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 9, 51))
+
+declare let f10: (...x: [number, string, ...boolean[]]) => void;
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 11, 18))
+
+declare let f11: (a: number, ...x: [string, ...boolean[]]) => void;
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 12, 18))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 12, 28))
+
+declare let f12: (a: number, b: string, ...x: [...boolean[]]) => void;
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 13, 18))
+>b : Symbol(b, Decl(genericRestParameters2.ts, 13, 28))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 13, 39))
+
+declare let f13: (a: number, b: string, ...c: boolean[]) => void;
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>a : Symbol(a, Decl(genericRestParameters2.ts, 14, 18))
+>b : Symbol(b, Decl(genericRestParameters2.ts, 14, 28))
+>c : Symbol(c, Decl(genericRestParameters2.ts, 14, 39))
+
+declare const ns: [number, string];
+>ns : Symbol(ns, Decl(genericRestParameters2.ts, 16, 13))
+
+declare const sn: [string, number];
+>sn : Symbol(sn, Decl(genericRestParameters2.ts, 17, 13))
+
+f10(42, "hello");
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+
+f10(42, "hello", true);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+
+f10(42, "hello", true, false);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+
+f10(t1[0], t1[1], t1[2], t1[3]);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>0 : Symbol(0)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>1 : Symbol(1)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f10(...t1);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f10(42, ...t2);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+f10(42, "hello", ...t3);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f10(42, "hello", true, ...t4);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+
+f10(42, "hello", true, ...t4, false, ...t3);
+>f10 : Symbol(f10, Decl(genericRestParameters2.ts, 11, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f11(42, "hello");
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+
+f11(42, "hello", true);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+
+f11(42, "hello", true, false);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+
+f11(t1[0], t1[1], t1[2], t1[3]);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>0 : Symbol(0)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>1 : Symbol(1)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f11(...t1);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f11(42, ...t2);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+f11(42, "hello", ...t3);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f11(42, "hello", true, ...t4);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+
+f11(42, "hello", true, ...t4, false, ...t3);
+>f11 : Symbol(f11, Decl(genericRestParameters2.ts, 12, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f12(42, "hello");
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+
+f12(42, "hello", true);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+
+f12(42, "hello", true, false);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+
+f12(t1[0], t1[1], t1[2], t1[3]);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>0 : Symbol(0)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>1 : Symbol(1)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f12(...t1);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f12(42, ...t2);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+f12(42, "hello", ...t3);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f12(42, "hello", true, ...t4);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+
+f12(42, "hello", true, ...t4, false, ...t3);
+>f12 : Symbol(f12, Decl(genericRestParameters2.ts, 13, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f13(42, "hello");
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+
+f13(42, "hello", true);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+
+f13(42, "hello", true, false);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+
+f13(t1[0], t1[1], t1[2], t1[3]);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>0 : Symbol(0)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>1 : Symbol(1)
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f13(...t1);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f13(42, ...t2);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+f13(42, "hello", ...t3);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f13(42, "hello", true, ...t4);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+
+f13(42, "hello", true, ...t4, false, ...t3);
+>f13 : Symbol(f13, Decl(genericRestParameters2.ts, 14, 11))
+>t4 : Symbol(t4, Decl(genericRestParameters2.ts, 3, 13))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+declare const f20: <T extends unknown[]>(...args: T) => T;
+>f20 : Symbol(f20, Decl(genericRestParameters2.ts, 59, 13))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 59, 20))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 59, 41))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 59, 20))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 59, 20))
+
+f20(...t1);
+>f20 : Symbol(f20, Decl(genericRestParameters2.ts, 59, 13))
+>t1 : Symbol(t1, Decl(genericRestParameters2.ts, 0, 13))
+
+f20(42, ...t2);
+>f20 : Symbol(f20, Decl(genericRestParameters2.ts, 59, 13))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+f20(42, "hello", ...t3);
+>f20 : Symbol(f20, Decl(genericRestParameters2.ts, 59, 13))
+>t3 : Symbol(t3, Decl(genericRestParameters2.ts, 2, 13))
+
+f20(42, "hello", ...t2, true);
+>f20 : Symbol(f20, Decl(genericRestParameters2.ts, 59, 13))
+>t2 : Symbol(t2, Decl(genericRestParameters2.ts, 1, 13))
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 66, 16))
+>Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 66, 16))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 66, 50))
+>U : Symbol(U, Decl(genericRestParameters2.ts, 66, 64), Decl(genericRestParameters2.ts, 66, 97))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 66, 83))
+>U : Symbol(U, Decl(genericRestParameters2.ts, 66, 64), Decl(genericRestParameters2.ts, 66, 97))
+>U : Symbol(U, Decl(genericRestParameters2.ts, 66, 64), Decl(genericRestParameters2.ts, 66, 97))
+
+type T01 = Parameters<(x: number, y: string, ...z: boolean[]) => void>;
+>T01 : Symbol(T01, Decl(genericRestParameters2.ts, 66, 121))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 68, 23))
+>y : Symbol(y, Decl(genericRestParameters2.ts, 68, 33))
+>z : Symbol(z, Decl(genericRestParameters2.ts, 68, 44))
+
+type T02 = Parameters<(...args: [number, string, ...boolean[]]) => void>;
+>T02 : Symbol(T02, Decl(genericRestParameters2.ts, 68, 71))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 69, 23))
+
+type T03 = Parameters<new (x: number, y: string, ...z: boolean[]) => void>;
+>T03 : Symbol(T03, Decl(genericRestParameters2.ts, 69, 73))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 70, 27))
+>y : Symbol(y, Decl(genericRestParameters2.ts, 70, 37))
+>z : Symbol(z, Decl(genericRestParameters2.ts, 70, 48))
+
+type T04 = Parameters<new (...args: [number, string, ...boolean[]]) => void>;
+>T04 : Symbol(T04, Decl(genericRestParameters2.ts, 70, 75))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 71, 27))
+
+type T05<T extends any[]> = Parameters<(x: string, ...args: T) => void>;
+>T05 : Symbol(T05, Decl(genericRestParameters2.ts, 71, 77))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 72, 9))
+>Parameters : Symbol(Parameters, Decl(genericRestParameters2.ts, 64, 30))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 72, 40))
+>args : Symbol(args, Decl(genericRestParameters2.ts, 72, 50))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 72, 9))
+
+type T06 = T05<[number, ...boolean[]]>;
+>T06 : Symbol(T06, Decl(genericRestParameters2.ts, 72, 72))
+>T05 : Symbol(T05, Decl(genericRestParameters2.ts, 71, 77))
+
+type P1<T extends Function> = T extends (head: infer A, ...tail: infer B) => any ? { head: A, tail: B } : any[];
+>P1 : Symbol(P1, Decl(genericRestParameters2.ts, 73, 39))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 75, 8))
+>Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(genericRestParameters2.ts, 75, 8))
+>head : Symbol(head, Decl(genericRestParameters2.ts, 75, 41))
+>A : Symbol(A, Decl(genericRestParameters2.ts, 75, 52))
+>tail : Symbol(tail, Decl(genericRestParameters2.ts, 75, 55))
+>B : Symbol(B, Decl(genericRestParameters2.ts, 75, 70))
+>head : Symbol(head, Decl(genericRestParameters2.ts, 75, 84))
+>A : Symbol(A, Decl(genericRestParameters2.ts, 75, 52))
+>tail : Symbol(tail, Decl(genericRestParameters2.ts, 75, 93))
+>B : Symbol(B, Decl(genericRestParameters2.ts, 75, 70))
+
+type T10 = P1<(x: number, y: string, ...z: boolean[]) => void>;
+>T10 : Symbol(T10, Decl(genericRestParameters2.ts, 75, 112))
+>P1 : Symbol(P1, Decl(genericRestParameters2.ts, 73, 39))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 77, 15))
+>y : Symbol(y, Decl(genericRestParameters2.ts, 77, 25))
+>z : Symbol(z, Decl(genericRestParameters2.ts, 77, 36))
+
+type T11 = P1<(...z: number[]) => void>;
+>T11 : Symbol(T11, Decl(genericRestParameters2.ts, 77, 63))
+>P1 : Symbol(P1, Decl(genericRestParameters2.ts, 73, 39))
+>z : Symbol(z, Decl(genericRestParameters2.ts, 78, 15))
+
+type T12 = P1<(x: number, y: number) => void>;
+>T12 : Symbol(T12, Decl(genericRestParameters2.ts, 78, 40))
+>P1 : Symbol(P1, Decl(genericRestParameters2.ts, 73, 39))
+>x : Symbol(x, Decl(genericRestParameters2.ts, 79, 15))
+>y : Symbol(y, Decl(genericRestParameters2.ts, 79, 25))
+

tests/baselines/reference/genericRestParameters2.types

@@ -0,0 +1,500 @@
+=== tests/cases/conformance/types/rest/genericRestParameters2.ts ===
+declare const t1: [number, string, ...boolean[]];
+>t1 : [number, string, ...boolean[]]
+
+declare const t2: [string, ...boolean[]];
+>t2 : [string, ...boolean[]]
+
+declare const t3: [...boolean[]];
+>t3 : boolean[]
+
+declare const t4: [];
+>t4 : []
+
+declare let f00: (...x: [number, string, boolean]) => void;
+>f00 : (x_0: number, x_1: string, x_2: boolean) => void
+>x : [number, string, boolean]
+
+declare let f01: (a: number, ...x: [string, boolean]) => void;
+>f01 : (a: number, x_0: string, x_1: boolean) => void
+>a : number
+>x : [string, boolean]
+
+declare let f02: (a: number, b: string, ...x: [boolean]) => void;
+>f02 : (a: number, b: string, x_0: boolean) => void
+>a : number
+>b : string
+>x : [boolean]
+
+declare let f03: (a: number, b: string, c: boolean) => void;
+>f03 : (a: number, b: string, c: boolean) => void
+>a : number
+>b : string
+>c : boolean
+
+declare let f04: (a: number, b: string, c: boolean, ...x: []) => void;
+>f04 : (a: number, b: string, c: boolean) => void
+>a : number
+>b : string
+>c : boolean
+>x : []
+
+declare let f10: (...x: [number, string, ...boolean[]]) => void;
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>x : [number, string, ...boolean[]]
+
+declare let f11: (a: number, ...x: [string, ...boolean[]]) => void;
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>a : number
+>x : [string, ...boolean[]]
+
+declare let f12: (a: number, b: string, ...x: [...boolean[]]) => void;
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>a : number
+>b : string
+>x : boolean[]
+
+declare let f13: (a: number, b: string, ...c: boolean[]) => void;
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>a : number
+>b : string
+>c : boolean[]
+
+declare const ns: [number, string];
+>ns : [number, string]
+
+declare const sn: [string, number];
+>sn : [string, number]
+
+f10(42, "hello");
+>f10(42, "hello") : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+
+f10(42, "hello", true);
+>f10(42, "hello", true) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f10(42, "hello", true, false);
+>f10(42, "hello", true, false) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>false : false
+
+f10(t1[0], t1[1], t1[2], t1[3]);
+>f10(t1[0], t1[1], t1[2], t1[3]) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>t1[0] : number
+>t1 : [number, string, ...boolean[]]
+>0 : 0
+>t1[1] : string
+>t1 : [number, string, ...boolean[]]
+>1 : 1
+>t1[2] : boolean
+>t1 : [number, string, ...boolean[]]
+>2 : 2
+>t1[3] : boolean
+>t1 : [number, string, ...boolean[]]
+>3 : 3
+
+f10(...t1);
+>f10(...t1) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>...t1 : string | number | boolean
+>t1 : [number, string, ...boolean[]]
+
+f10(42, ...t2);
+>f10(42, ...t2) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+
+f10(42, "hello", ...t3);
+>f10(42, "hello", ...t3) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>...t3 : boolean
+>t3 : boolean[]
+
+f10(42, "hello", true, ...t4);
+>f10(42, "hello", true, ...t4) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+
+f10(42, "hello", true, ...t4, false, ...t3);
+>f10(42, "hello", true, ...t4, false, ...t3) : void
+>f10 : (x_0: number, x_1: string, ...x_2: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+>false : false
+>...t3 : boolean
+>t3 : boolean[]
+
+f11(42, "hello");
+>f11(42, "hello") : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+
+f11(42, "hello", true);
+>f11(42, "hello", true) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f11(42, "hello", true, false);
+>f11(42, "hello", true, false) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>false : false
+
+f11(t1[0], t1[1], t1[2], t1[3]);
+>f11(t1[0], t1[1], t1[2], t1[3]) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>t1[0] : number
+>t1 : [number, string, ...boolean[]]
+>0 : 0
+>t1[1] : string
+>t1 : [number, string, ...boolean[]]
+>1 : 1
+>t1[2] : boolean
+>t1 : [number, string, ...boolean[]]
+>2 : 2
+>t1[3] : boolean
+>t1 : [number, string, ...boolean[]]
+>3 : 3
+
+f11(...t1);
+>f11(...t1) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>...t1 : string | number | boolean
+>t1 : [number, string, ...boolean[]]
+
+f11(42, ...t2);
+>f11(42, ...t2) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+
+f11(42, "hello", ...t3);
+>f11(42, "hello", ...t3) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>...t3 : boolean
+>t3 : boolean[]
+
+f11(42, "hello", true, ...t4);
+>f11(42, "hello", true, ...t4) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+
+f11(42, "hello", true, ...t4, false, ...t3);
+>f11(42, "hello", true, ...t4, false, ...t3) : void
+>f11 : (a: number, x_0: string, ...x_1: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+>false : false
+>...t3 : boolean
+>t3 : boolean[]
+
+f12(42, "hello");
+>f12(42, "hello") : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+
+f12(42, "hello", true);
+>f12(42, "hello", true) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f12(42, "hello", true, false);
+>f12(42, "hello", true, false) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>false : false
+
+f12(t1[0], t1[1], t1[2], t1[3]);
+>f12(t1[0], t1[1], t1[2], t1[3]) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>t1[0] : number
+>t1 : [number, string, ...boolean[]]
+>0 : 0
+>t1[1] : string
+>t1 : [number, string, ...boolean[]]
+>1 : 1
+>t1[2] : boolean
+>t1 : [number, string, ...boolean[]]
+>2 : 2
+>t1[3] : boolean
+>t1 : [number, string, ...boolean[]]
+>3 : 3
+
+f12(...t1);
+>f12(...t1) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>...t1 : string | number | boolean
+>t1 : [number, string, ...boolean[]]
+
+f12(42, ...t2);
+>f12(42, ...t2) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+
+f12(42, "hello", ...t3);
+>f12(42, "hello", ...t3) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>...t3 : boolean
+>t3 : boolean[]
+
+f12(42, "hello", true, ...t4);
+>f12(42, "hello", true, ...t4) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+
+f12(42, "hello", true, ...t4, false, ...t3);
+>f12(42, "hello", true, ...t4, false, ...t3) : void
+>f12 : (a: number, b: string, ...x: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+>false : false
+>...t3 : boolean
+>t3 : boolean[]
+
+f13(42, "hello");
+>f13(42, "hello") : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+
+f13(42, "hello", true);
+>f13(42, "hello", true) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+
+f13(42, "hello", true, false);
+>f13(42, "hello", true, false) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>false : false
+
+f13(t1[0], t1[1], t1[2], t1[3]);
+>f13(t1[0], t1[1], t1[2], t1[3]) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>t1[0] : number
+>t1 : [number, string, ...boolean[]]
+>0 : 0
+>t1[1] : string
+>t1 : [number, string, ...boolean[]]
+>1 : 1
+>t1[2] : boolean
+>t1 : [number, string, ...boolean[]]
+>2 : 2
+>t1[3] : boolean
+>t1 : [number, string, ...boolean[]]
+>3 : 3
+
+f13(...t1);
+>f13(...t1) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>...t1 : string | number | boolean
+>t1 : [number, string, ...boolean[]]
+
+f13(42, ...t2);
+>f13(42, ...t2) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+
+f13(42, "hello", ...t3);
+>f13(42, "hello", ...t3) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>...t3 : boolean
+>t3 : boolean[]
+
+f13(42, "hello", true, ...t4);
+>f13(42, "hello", true, ...t4) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+
+f13(42, "hello", true, ...t4, false, ...t3);
+>f13(42, "hello", true, ...t4, false, ...t3) : void
+>f13 : (a: number, b: string, ...c: boolean[]) => void
+>42 : 42
+>"hello" : "hello"
+>true : true
+>...t4 : never
+>t4 : []
+>false : false
+>...t3 : boolean
+>t3 : boolean[]
+
+declare const f20: <T extends unknown[]>(...args: T) => T;
+>f20 : <T extends unknown[]>(...args: T) => T
+>T : T
+>args : T
+>T : T
+>T : T
+
+f20(...t1);
+>f20(...t1) : [number, string, ...boolean[]]
+>f20 : <T extends unknown[]>(...args: T) => T
+>...t1 : string | number | boolean
+>t1 : [number, string, ...boolean[]]
+
+f20(42, ...t2);
+>f20(42, ...t2) : [number, string, ...boolean[]]
+>f20 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+
+f20(42, "hello", ...t3);
+>f20(42, "hello", ...t3) : [number, string, ...boolean[]]
+>f20 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>...t3 : boolean
+>t3 : boolean[]
+
+f20(42, "hello", ...t2, true);
+>f20(42, "hello", ...t2, true) : [number, string, ...(string | boolean)[]]
+>f20 : <T extends unknown[]>(...args: T) => T
+>42 : 42
+>"hello" : "hello"
+>...t2 : string | boolean
+>t2 : [string, ...boolean[]]
+>true : true
+
+type Parameters<T extends Function> = T extends ((...args: infer U) => any) | (new(...args: infer U) => any) ? U : any[];
+>Parameters : Parameters<T>
+>T : T
+>Function : Function
+>T : T
+>args : U
+>U : U
+>args : U
+>U : U
+>U : U
+
+type T01 = Parameters<(x: number, y: string, ...z: boolean[]) => void>;
+>T01 : [number, string, ...boolean[]]
+>Parameters : Parameters<T>
+>x : number
+>y : string
+>z : boolean[]
+
+type T02 = Parameters<(...args: [number, string, ...boolean[]]) => void>;
+>T02 : [number, string, ...boolean[]]
+>Parameters : Parameters<T>
+>args : [number, string, ...boolean[]]
+
+type T03 = Parameters<new (x: number, y: string, ...z: boolean[]) => void>;
+>T03 : [number, string, ...boolean[]]
+>Parameters : Parameters<T>
+>x : number
+>y : string
+>z : boolean[]
+
+type T04 = Parameters<new (...args: [number, string, ...boolean[]]) => void>;
+>T04 : [number, string, ...boolean[]]
+>Parameters : Parameters<T>
+>args : [number, string, ...boolean[]]
+
+type T05<T extends any[]> = Parameters<(x: string, ...args: T) => void>;
+>T05 : Parameters<(x: string, ...args: T) => void>
+>T : T
+>Parameters : Parameters<T>
+>x : string
+>args : T
+>T : T
+
+type T06 = T05<[number, ...boolean[]]>;
+>T06 : [string, number, ...boolean[]]
+>T05 : Parameters<(x: string, ...args: T) => void>
+
+type P1<T extends Function> = T extends (head: infer A, ...tail: infer B) => any ? { head: A, tail: B } : any[];
+>P1 : P1<T>
+>T : T
+>Function : Function
+>T : T
+>head : A
+>A : A
+>tail : B
+>B : B
+>head : A
+>A : A
+>tail : B
+>B : B
+
+type T10 = P1<(x: number, y: string, ...z: boolean[]) => void>;
+>T10 : { head: number; tail: [string, ...boolean[]]; }
+>P1 : P1<T>
+>x : number
+>y : string
+>z : boolean[]
+
+type T11 = P1<(...z: number[]) => void>;
+>T11 : { head: number; tail: number[]; }
+>P1 : P1<T>
+>z : number[]
+
+type T12 = P1<(x: number, y: number) => void>;
+>T12 : { head: number; tail: [number]; }
+>P1 : P1<T>
+>x : number
+>y : number
+

tests/baselines/reference/initializedDestructuringAssignmentTypes.types

@@ -3,13 +3,13 @@ const [, a = ''] = ''.match('') || [];
 > : undefined
 >a : string
 >'' : ""
->''.match('') || [] : RegExpMatchArray | [undefined, ""]
+>''.match('') || [] : RegExpMatchArray
 >''.match('') : RegExpMatchArray
 >''.match : (regexp: string | RegExp) => RegExpMatchArray
 >'' : ""
 >match : (regexp: string | RegExp) => RegExpMatchArray
 >'' : ""
->[] : [undefined, ""]
+>[] : [undefined?, ""?]
 
 a.toFixed()
 >a.toFixed() : any

tests/baselines/reference/iterableArrayPattern13.errors.txt

@@ -0,0 +1,25 @@
+tests/cases/conformance/es6/destructuring/iterableArrayPattern13.ts(17,5): error TS2345: Argument of type 'FooIterator' is not assignable to parameter of type '[any, ...any[]]'.
+  Property '0' is missing in type 'FooIterator'.
+
+
+==== tests/cases/conformance/es6/destructuring/iterableArrayPattern13.ts (1 errors) ====
+    class Bar { x }
+    class Foo extends Bar { y }
+    class FooIterator {
+        next() {
+            return {
+                value: new Foo,
+                done: false
+            };
+        }
+    
+        [Symbol.iterator]() {
+            return this;
+        }
+    }
+    
+    function fun([a, ...b]) { }
+    fun(new FooIterator);
+        ~~~~~~~~~~~~~~~
+!!! error TS2345: Argument of type 'FooIterator' is not assignable to parameter of type '[any, ...any[]]'.
+!!! error TS2345:   Property '0' is missing in type 'FooIterator'.

tests/baselines/reference/iterableArrayPattern13.types

@@ -41,13 +41,13 @@ class FooIterator {
 }
 
 function fun([a, ...b]) { }
->fun : ([a, ...b]: Iterable<any>) => void
+>fun : ([a, ...b]: [any, ...any[]]) => void
 >a : any
 >b : any[]
 
 fun(new FooIterator);
 >fun(new FooIterator) : void
->fun : ([a, ...b]: Iterable<any>) => void
+>fun : ([a, ...b]: [any, ...any[]]) => void
 >new FooIterator : FooIterator
 >FooIterator : typeof FooIterator
 

tests/baselines/reference/iterableArrayPattern14.types

@@ -41,13 +41,13 @@ class FooIterator {
 }
 
 function fun(...[a, ...b]) { }
->fun : (...[a, ...b]: Iterable<any>) => void
+>fun : (__0_0: any, ...__0_1: any[]) => void
 >a : any
 >b : any[]
 
 fun(new FooIterator);
 >fun(new FooIterator) : void
->fun : (...[a, ...b]: Iterable<any>) => void
+>fun : (__0_0: any, ...__0_1: any[]) => void
 >new FooIterator : FooIterator
 >FooIterator : typeof FooIterator
 

tests/baselines/reference/iterableArrayPattern24.types

@@ -5,7 +5,7 @@ var a: string, b: boolean[];
 
 [a, ...b] = { 0: "", 1: true };
 >[a, ...b] = { 0: "", 1: true } : { 0: string; 1: true; }
->[a, ...b] : (string | boolean)[]
+>[a, ...b] : [string, ...boolean[]]
 >a : string
 >...b : boolean
 >b : boolean[]

tests/baselines/reference/iterableArrayPattern25.errors.txt

@@ -1,8 +1,11 @@
 tests/cases/conformance/es6/destructuring/iterableArrayPattern25.ts(1,33): error TS2501: A rest element cannot contain a binding pattern.
+tests/cases/conformance/es6/destructuring/iterableArrayPattern25.ts(2,1): error TS2554: Expected 2 arguments, but got 1.
 
 
-==== tests/cases/conformance/es6/destructuring/iterableArrayPattern25.ts (1 errors) ====
+==== tests/cases/conformance/es6/destructuring/iterableArrayPattern25.ts (2 errors) ====
     function takeFirstTwoEntries(...[[k1, v1], [k2, v2]]) { }
                                     ~~~~~~~~~~~~~~~~~~~~
 !!! error TS2501: A rest element cannot contain a binding pattern.
-    takeFirstTwoEntries(new Map([["", 0], ["hello", 1]]));
+    takeFirstTwoEntries(new Map([["", 0], ["hello", 1]]));
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2554: Expected 2 arguments, but got 1.

tests/baselines/reference/iterableArrayPattern25.types

@@ -1,6 +1,6 @@
 === tests/cases/conformance/es6/destructuring/iterableArrayPattern25.ts ===
 function takeFirstTwoEntries(...[[k1, v1], [k2, v2]]) { }
->takeFirstTwoEntries : (...[[k1, v1], [k2, v2]]: [[any, any], [any, any]]) => void
+>takeFirstTwoEntries : (__0_0: [any, any], __0_1: [any, any]) => void
 >k1 : any
 >v1 : any
 >k2 : any
@@ -8,7 +8,7 @@ function takeFirstTwoEntries(...[[k1, v1], [k2, v2]]) { }
 
 takeFirstTwoEntries(new Map([["", 0], ["hello", 1]]));
 >takeFirstTwoEntries(new Map([["", 0], ["hello", 1]])) : void
->takeFirstTwoEntries : (...[[k1, v1], [k2, v2]]: [[any, any], [any, any]]) => void
+>takeFirstTwoEntries : (__0_0: [any, any], __0_1: [any, any]) => void
 >new Map([["", 0], ["hello", 1]]) : Map<string, number>
 >Map : MapConstructor
 >[["", 0], ["hello", 1]] : [string, number][]

tests/baselines/reference/iterableArrayPattern4.types

@@ -48,7 +48,7 @@ var a: Bar, b: Bar[];
 
 [a, ...b] = new FooIterator
 >[a, ...b] = new FooIterator : FooIterator
->[a, ...b] : Bar[]
+>[a, ...b] : [Bar, ...Bar[]]
 >a : Bar
 >...b : Bar
 >b : Bar[]

tests/baselines/reference/iterableArrayPattern6.types

@@ -47,7 +47,7 @@ var a: Bar, b: string[];
 
 [a, ...b] = new FooIterator;
 >[a, ...b] = new FooIterator : FooIterator
->[a, ...b] : (string | Bar)[]
+>[a, ...b] : [Bar, ...string[]]
 >a : Bar
 >...b : string
 >b : string[]

tests/baselines/reference/iterableArrayPattern8.types

@@ -47,7 +47,7 @@ var a: Bar, b: string;
 
 [a, ...b] = new FooIterator;
 >[a, ...b] = new FooIterator : FooIterator
->[a, ...b] : (string | Bar)[]
+>[a, ...b] : [Bar, ...string[]]
 >a : Bar
 >...b : string
 >b : string

tests/baselines/reference/keyofAndIndexedAccessErrors.errors.txt

@@ -15,7 +15,6 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(35,21): error
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(36,21): error TS2538: Type 'boolean' cannot be used as an index type.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(41,31): error TS2538: Type 'boolean' cannot be used as an index type.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(46,16): error TS2538: Type 'boolean' cannot be used as an index type.
-tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(49,12): error TS1122: A tuple type element list cannot be empty.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(63,33): error TS2345: Argument of type '"size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
 tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(64,33): error TS2345: Argument of type '"name" | "size"' is not assignable to parameter of type '"name" | "width" | "height" | "visible"'.
   Type '"size"' is not assignable to type '"name" | "width" | "height" | "visible"'.
@@ -61,7 +60,7 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(117,5): error
   Type 'T' is not assignable to type 'U'.
 
 
-==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (34 errors) ====
+==== tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts (33 errors) ====
     class Shape {
         name: string;
         width: number;
@@ -145,8 +144,6 @@ tests/cases/conformance/types/keyof/keyofAndIndexedAccessErrors.ts(117,5): error
     
     type T60 = {}["toString"];
     type T61 = []["toString"];
-               ~~
-!!! error TS1122: A tuple type element list cannot be empty.
     
     declare let cond: boolean;
     

tests/baselines/reference/noImplicitAnyDestructuringParameterDeclaration.types

@@ -7,7 +7,7 @@ function f1([a], {b}, c, d) { // error
 >d : any
 }
 function f2([a = undefined], {b = null}, c = undefined, d = null) { // error
->f2 : ([a]: [any], { b }: { b?: any; }, c?: any, d?: any) => void
+>f2 : ([a]: [any?], { b }: { b?: any; }, c?: any, d?: any) => void
 >a : any
 >undefined : undefined
 >b : any

tests/baselines/reference/noImplicitAnyDestructuringVarDeclaration.types

@@ -44,5 +44,5 @@ var [a4] = [undefined], {b4} = { b4: null }, c4 = undefined, d4 = null; // error
 var [a5 = undefined] = []; // error
 >a5 : any
 >undefined : undefined
->[] : [undefined]
+>[] : [undefined?]
 

tests/baselines/reference/objectRestAssignment.types

@@ -59,9 +59,9 @@ var { a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit;
 ({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit);
 >({ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit) : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
 >{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } = overEmit : { a: { ka: string; x: string; }[]; b: { z: string; ki: string; ku: string; }; ke: string; ko: string; }
->{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } : { ke: string; ko: string; a: { ka: string; x: string; }[]; b: { ki: string; ku: string; z: string; }; }
->a : { ka: string; x: string; }[]
->[{ ...nested2 }, ...y] : { ka: string; x: string; }[]
+>{ a: [{ ...nested2 }, ...y], b: { z, ...c }, ...rest2 } : { ke: string; ko: string; a: [{ ka: string; x: string; }, ...{ ka: string; x: string; }[]]; b: { ki: string; ku: string; z: string; }; }
+>a : [{ ka: string; x: string; }, ...{ ka: string; x: string; }[]]
+>[{ ...nested2 }, ...y] : [{ ka: string; x: string; }, ...{ ka: string; x: string; }[]]
 >{ ...nested2 } : { ka: string; x: string; }
 >nested2 : { ka: string; x: string; }
 >...y : { ka: string; x: string; }

tests/baselines/reference/optionalTupleElements1.errors.txt

@@ -0,0 +1,105 @@
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(11,29): error TS1257: A required element cannot follow an optional element.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(15,5): error TS2322: Type '[number, string, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+  Types of property '2' are incompatible.
+    Type 'boolean | undefined' is not assignable to type 'boolean'.
+      Type 'undefined' is not assignable to type 'boolean'.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(16,5): error TS2322: Type '[number, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+  Types of property '1' are incompatible.
+    Type 'string | undefined' is not assignable to type 'string'.
+      Type 'undefined' is not assignable to type 'string'.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(17,5): error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+  Types of property '0' are incompatible.
+    Type 'number | undefined' is not assignable to type 'number'.
+      Type 'undefined' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(20,5): error TS2322: Type '[number, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, (boolean | undefined)?]'.
+  Types of property '1' are incompatible.
+    Type 'string | undefined' is not assignable to type 'string'.
+      Type 'undefined' is not assignable to type 'string'.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(21,5): error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, (boolean | undefined)?]'.
+  Types of property '0' are incompatible.
+    Type 'number | undefined' is not assignable to type 'number'.
+      Type 'undefined' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/optionalTupleElements1.ts(25,5): error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, (string | undefined)?, (boolean | undefined)?]'.
+  Types of property '0' are incompatible.
+    Type 'number | undefined' is not assignable to type 'number'.
+      Type 'undefined' is not assignable to type 'number'.
+
+
+==== tests/cases/conformance/types/tuple/optionalTupleElements1.ts (7 errors) ====
+    type T1 = [number, string, boolean];
+    type T2 = [number, string, boolean?];
+    type T3 = [number, string?, boolean?];
+    type T4 = [number?, string?, boolean?];
+    
+    type L1 = T1["length"];
+    type L2 = T2["length"];
+    type L3 = T3["length"];
+    type L4 = T4["length"];
+    
+    type T5 = [number, string?, boolean];  // Error
+                                ~~~~~~~
+!!! error TS1257: A required element cannot follow an optional element.
+    
+    function f1(t1: T1, t2: T2, t3: T3, t4: T4) {
+        t1 = t1;
+        t1 = t2;  // Error
+        ~~
+!!! error TS2322: Type '[number, string, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+!!! error TS2322:   Types of property '2' are incompatible.
+!!! error TS2322:     Type 'boolean | undefined' is not assignable to type 'boolean'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'boolean'.
+        t1 = t3;  // Error
+        ~~
+!!! error TS2322: Type '[number, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+!!! error TS2322:   Types of property '1' are incompatible.
+!!! error TS2322:     Type 'string | undefined' is not assignable to type 'string'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'string'.
+        t1 = t4;  // Error
+        ~~
+!!! error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, boolean]'.
+!!! error TS2322:   Types of property '0' are incompatible.
+!!! error TS2322:     Type 'number | undefined' is not assignable to type 'number'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'number'.
+        t2 = t1;
+        t2 = t2;
+        t2 = t3;  // Error
+        ~~
+!!! error TS2322: Type '[number, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, (boolean | undefined)?]'.
+!!! error TS2322:   Types of property '1' are incompatible.
+!!! error TS2322:     Type 'string | undefined' is not assignable to type 'string'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'string'.
+        t2 = t4;  // Error
+        ~~
+!!! error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, string, (boolean | undefined)?]'.
+!!! error TS2322:   Types of property '0' are incompatible.
+!!! error TS2322:     Type 'number | undefined' is not assignable to type 'number'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'number'.
+        t3 = t1;
+        t3 = t2;
+        t3 = t3;
+        t3 = t4;  // Error
+        ~~
+!!! error TS2322: Type '[(number | undefined)?, (string | undefined)?, (boolean | undefined)?]' is not assignable to type '[number, (string | undefined)?, (boolean | undefined)?]'.
+!!! error TS2322:   Types of property '0' are incompatible.
+!!! error TS2322:     Type 'number | undefined' is not assignable to type 'number'.
+!!! error TS2322:       Type 'undefined' is not assignable to type 'number'.
+        t4 = t1;
+        t4 = t2;
+        t4 = t3;
+        t4 = t4;
+    }
+    
+    let t2: T2;
+    let t3: T3;
+    let t4: T4;
+    
+    t2 = [42, "hello"];
+    t3 = [42, "hello"];
+    t3 = [42,,true]
+    t3 = [42];
+    t4 = [42, "hello"];
+    t4 = [42,,true];
+    t4 = [,"hello", true];
+    t4 = [,,true];
+    t4 = [];
+    

tests/baselines/reference/optionalTupleElements1.js

@@ -0,0 +1,95 @@
+//// [optionalTupleElements1.ts]
+type T1 = [number, string, boolean];
+type T2 = [number, string, boolean?];
+type T3 = [number, string?, boolean?];
+type T4 = [number?, string?, boolean?];
+
+type L1 = T1["length"];
+type L2 = T2["length"];
+type L3 = T3["length"];
+type L4 = T4["length"];
+
+type T5 = [number, string?, boolean];  // Error
+
+function f1(t1: T1, t2: T2, t3: T3, t4: T4) {
+    t1 = t1;
+    t1 = t2;  // Error
+    t1 = t3;  // Error
+    t1 = t4;  // Error
+    t2 = t1;
+    t2 = t2;
+    t2 = t3;  // Error
+    t2 = t4;  // Error
+    t3 = t1;
+    t3 = t2;
+    t3 = t3;
+    t3 = t4;  // Error
+    t4 = t1;
+    t4 = t2;
+    t4 = t3;
+    t4 = t4;
+}
+
+let t2: T2;
+let t3: T3;
+let t4: T4;
+
+t2 = [42, "hello"];
+t3 = [42, "hello"];
+t3 = [42,,true]
+t3 = [42];
+t4 = [42, "hello"];
+t4 = [42,,true];
+t4 = [,"hello", true];
+t4 = [,,true];
+t4 = [];
+
+
+//// [optionalTupleElements1.js]
+"use strict";
+function f1(t1, t2, t3, t4) {
+    t1 = t1;
+    t1 = t2; // Error
+    t1 = t3; // Error
+    t1 = t4; // Error
+    t2 = t1;
+    t2 = t2;
+    t2 = t3; // Error
+    t2 = t4; // Error
+    t3 = t1;
+    t3 = t2;
+    t3 = t3;
+    t3 = t4; // Error
+    t4 = t1;
+    t4 = t2;
+    t4 = t3;
+    t4 = t4;
+}
+var t2;
+var t3;
+var t4;
+t2 = [42, "hello"];
+t3 = [42, "hello"];
+t3 = [42, , true];
+t3 = [42];
+t4 = [42, "hello"];
+t4 = [42, , true];
+t4 = [, "hello", true];
+t4 = [, , true];
+t4 = [];
+
+
+//// [optionalTupleElements1.d.ts]
+declare type T1 = [number, string, boolean];
+declare type T2 = [number, string, boolean?];
+declare type T3 = [number, string?, boolean?];
+declare type T4 = [number?, string?, boolean?];
+declare type L1 = T1["length"];
+declare type L2 = T2["length"];
+declare type L3 = T3["length"];
+declare type L4 = T4["length"];
+declare type T5 = [number, string?, boolean];
+declare function f1(t1: T1, t2: T2, t3: T3, t4: T4): void;
+declare let t2: T2;
+declare let t3: T3;
+declare let t4: T4;

tests/baselines/reference/optionalTupleElements1.symbols

@@ -0,0 +1,147 @@
+=== tests/cases/conformance/types/tuple/optionalTupleElements1.ts ===
+type T1 = [number, string, boolean];
+>T1 : Symbol(T1, Decl(optionalTupleElements1.ts, 0, 0))
+
+type T2 = [number, string, boolean?];
+>T2 : Symbol(T2, Decl(optionalTupleElements1.ts, 0, 36))
+
+type T3 = [number, string?, boolean?];
+>T3 : Symbol(T3, Decl(optionalTupleElements1.ts, 1, 37))
+
+type T4 = [number?, string?, boolean?];
+>T4 : Symbol(T4, Decl(optionalTupleElements1.ts, 2, 38))
+
+type L1 = T1["length"];
+>L1 : Symbol(L1, Decl(optionalTupleElements1.ts, 3, 39))
+>T1 : Symbol(T1, Decl(optionalTupleElements1.ts, 0, 0))
+
+type L2 = T2["length"];
+>L2 : Symbol(L2, Decl(optionalTupleElements1.ts, 5, 23))
+>T2 : Symbol(T2, Decl(optionalTupleElements1.ts, 0, 36))
+
+type L3 = T3["length"];
+>L3 : Symbol(L3, Decl(optionalTupleElements1.ts, 6, 23))
+>T3 : Symbol(T3, Decl(optionalTupleElements1.ts, 1, 37))
+
+type L4 = T4["length"];
+>L4 : Symbol(L4, Decl(optionalTupleElements1.ts, 7, 23))
+>T4 : Symbol(T4, Decl(optionalTupleElements1.ts, 2, 38))
+
+type T5 = [number, string?, boolean];  // Error
+>T5 : Symbol(T5, Decl(optionalTupleElements1.ts, 8, 23))
+
+function f1(t1: T1, t2: T2, t3: T3, t4: T4) {
+>f1 : Symbol(f1, Decl(optionalTupleElements1.ts, 10, 37))
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+>T1 : Symbol(T1, Decl(optionalTupleElements1.ts, 0, 0))
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+>T2 : Symbol(T2, Decl(optionalTupleElements1.ts, 0, 36))
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+>T3 : Symbol(T3, Decl(optionalTupleElements1.ts, 1, 37))
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+>T4 : Symbol(T4, Decl(optionalTupleElements1.ts, 2, 38))
+
+    t1 = t1;
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+
+    t1 = t2;  // Error
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+
+    t1 = t3;  // Error
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+
+    t1 = t4;  // Error
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+
+    t2 = t1;
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+
+    t2 = t2;
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+
+    t2 = t3;  // Error
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+
+    t2 = t4;  // Error
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+
+    t3 = t1;
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+
+    t3 = t2;
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+
+    t3 = t3;
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+
+    t3 = t4;  // Error
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+
+    t4 = t1;
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+>t1 : Symbol(t1, Decl(optionalTupleElements1.ts, 12, 12))
+
+    t4 = t2;
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 12, 19))
+
+    t4 = t3;
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 12, 27))
+
+    t4 = t4;
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 12, 35))
+}
+
+let t2: T2;
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 31, 3))
+>T2 : Symbol(T2, Decl(optionalTupleElements1.ts, 0, 36))
+
+let t3: T3;
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 32, 3))
+>T3 : Symbol(T3, Decl(optionalTupleElements1.ts, 1, 37))
+
+let t4: T4;
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+>T4 : Symbol(T4, Decl(optionalTupleElements1.ts, 2, 38))
+
+t2 = [42, "hello"];
+>t2 : Symbol(t2, Decl(optionalTupleElements1.ts, 31, 3))
+
+t3 = [42, "hello"];
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 32, 3))
+
+t3 = [42,,true]
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 32, 3))
+
+t3 = [42];
+>t3 : Symbol(t3, Decl(optionalTupleElements1.ts, 32, 3))
+
+t4 = [42, "hello"];
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+
+t4 = [42,,true];
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+
+t4 = [,"hello", true];
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+
+t4 = [,,true];
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+
+t4 = [];
+>t4 : Symbol(t4, Decl(optionalTupleElements1.ts, 33, 3))
+

tests/baselines/reference/optionalTupleElements1.types

@@ -0,0 +1,200 @@
+=== tests/cases/conformance/types/tuple/optionalTupleElements1.ts ===
+type T1 = [number, string, boolean];
+>T1 : [number, string, boolean]
+
+type T2 = [number, string, boolean?];
+>T2 : [number, string, (boolean | undefined)?]
+
+type T3 = [number, string?, boolean?];
+>T3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+type T4 = [number?, string?, boolean?];
+>T4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+type L1 = T1["length"];
+>L1 : 3
+>T1 : [number, string, boolean]
+
+type L2 = T2["length"];
+>L2 : 3 | 2
+>T2 : [number, string, (boolean | undefined)?]
+
+type L3 = T3["length"];
+>L3 : 3 | 2 | 1
+>T3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+type L4 = T4["length"];
+>L4 : 0 | 3 | 2 | 1
+>T4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+type T5 = [number, string?, boolean];  // Error
+>T5 : [number, string | undefined, boolean]
+
+function f1(t1: T1, t2: T2, t3: T3, t4: T4) {
+>f1 : (t1: [number, string, boolean], t2: [number, string, (boolean | undefined)?], t3: [number, (string | undefined)?, (boolean | undefined)?], t4: [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]) => void
+>t1 : [number, string, boolean]
+>T1 : [number, string, boolean]
+>t2 : [number, string, (boolean | undefined)?]
+>T2 : [number, string, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>T3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>T4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+    t1 = t1;
+>t1 = t1 : [number, string, boolean]
+>t1 : [number, string, boolean]
+>t1 : [number, string, boolean]
+
+    t1 = t2;  // Error
+>t1 = t2 : [number, string, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+>t2 : [number, string, (boolean | undefined)?]
+
+    t1 = t3;  // Error
+>t1 = t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+    t1 = t4;  // Error
+>t1 = t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+    t2 = t1;
+>t2 = t1 : [number, string, boolean]
+>t2 : [number, string, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+
+    t2 = t2;
+>t2 = t2 : [number, string, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+
+    t2 = t3;  // Error
+>t2 = t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+    t2 = t4;  // Error
+>t2 = t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+    t3 = t1;
+>t3 = t1 : [number, string, boolean]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+
+    t3 = t2;
+>t3 = t2 : [number, string, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+
+    t3 = t3;
+>t3 = t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+    t3 = t4;  // Error
+>t3 = t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+    t4 = t1;
+>t4 = t1 : [number, string, boolean]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t1 : [number, string, boolean]
+
+    t4 = t2;
+>t4 = t2 : [number, string, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t2 : [number, string, (boolean | undefined)?]
+
+    t4 = t3;
+>t4 = t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+    t4 = t4;
+>t4 = t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+}
+
+let t2: T2;
+>t2 : [number, string, (boolean | undefined)?]
+>T2 : [number, string, (boolean | undefined)?]
+
+let t3: T3;
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>T3 : [number, (string | undefined)?, (boolean | undefined)?]
+
+let t4: T4;
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>T4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+
+t2 = [42, "hello"];
+>t2 = [42, "hello"] : [number, string]
+>t2 : [number, string, (boolean | undefined)?]
+>[42, "hello"] : [number, string]
+>42 : 42
+>"hello" : "hello"
+
+t3 = [42, "hello"];
+>t3 = [42, "hello"] : [number, string]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>[42, "hello"] : [number, string]
+>42 : 42
+>"hello" : "hello"
+
+t3 = [42,,true]
+>t3 = [42,,true] : [number, undefined, true]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>[42,,true] : [number, undefined, true]
+>42 : 42
+> : undefined
+>true : true
+
+t3 = [42];
+>t3 = [42] : [number]
+>t3 : [number, (string | undefined)?, (boolean | undefined)?]
+>[42] : [number]
+>42 : 42
+
+t4 = [42, "hello"];
+>t4 = [42, "hello"] : [number, string]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>[42, "hello"] : [number, string]
+>42 : 42
+>"hello" : "hello"
+
+t4 = [42,,true];
+>t4 = [42,,true] : [number, undefined, true]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>[42,,true] : [number, undefined, true]
+>42 : 42
+> : undefined
+>true : true
+
+t4 = [,"hello", true];
+>t4 = [,"hello", true] : [undefined, string, true]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>[,"hello", true] : [undefined, string, true]
+> : undefined
+>"hello" : "hello"
+>true : true
+
+t4 = [,,true];
+>t4 = [,,true] : [undefined, undefined, true]
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>[,,true] : [undefined, undefined, true]
+> : undefined
+> : undefined
+>true : true
+
+t4 = [];
+>t4 = [] : []
+>t4 : [(number | undefined)?, (string | undefined)?, (boolean | undefined)?]
+>[] : []
+

tests/baselines/reference/promiseEmptyTupleNoException.errors.txt

@@ -1,13 +1,10 @@
-tests/cases/compiler/promiseEmptyTupleNoException.ts(1,38): error TS1122: A tuple type element list cannot be empty.
 tests/cases/compiler/promiseEmptyTupleNoException.ts(3,3): error TS2322: Type 'any[]' is not assignable to type '[]'.
   Types of property 'length' are incompatible.
     Type 'number' is not assignable to type '0'.
 
 
-==== tests/cases/compiler/promiseEmptyTupleNoException.ts (2 errors) ====
+==== tests/cases/compiler/promiseEmptyTupleNoException.ts (1 errors) ====
     export async function get(): Promise<[]> {
-                                         ~~
-!!! error TS1122: A tuple type element list cannot be empty.
       let emails = [];
       return emails;
       ~~~~~~~~~~~~~~

tests/baselines/reference/recursiveLetConst.types

@@ -49,7 +49,7 @@ for (let [v] of v) { }
 let [x2 = x2] = []
 >x2 : any
 >x2 : any
->[] : [any]
+>[] : [any?]
 
 let z0 = () => z0;
 >z0 : () => any

tests/baselines/reference/restParameterWithBindingPattern2.types

@@ -1,6 +1,6 @@
 === tests/cases/compiler/restParameterWithBindingPattern2.ts ===
 function a(...[a, b]) { }
->a : (...[a, b]: [any, any]) => void
+>a : (__0_0: any, __0_1: any) => void
 >a : any
 >b : any
 

tests/baselines/reference/restTupleElements1.errors.txt

@@ -0,0 +1,138 @@
+tests/cases/conformance/types/tuple/restTupleElements1.ts(3,22): error TS1257: A required element cannot follow an optional element.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(8,13): error TS1256: A rest element must be last in a tuple type.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(9,13): error TS2574: A rest element type must be an array type.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(10,13): error TS2574: A rest element type must be an array type.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(10,16): error TS8020: JSDoc types can only be used inside documentation comments.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(23,31): error TS2344: Type 'number[]' does not satisfy the constraint '[number, ...number[]]'.
+  Property '0' is missing in type 'number[]'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(24,31): error TS2344: Type '[]' does not satisfy the constraint '[number, ...number[]]'.
+  Property '0' is missing in type '[]'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(29,18): error TS2344: Type 'number[]' does not satisfy the constraint '[number]'.
+  Property '0' is missing in type 'number[]'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(30,18): error TS2344: Type '[number, ...number[]]' does not satisfy the constraint '[number]'.
+  Types of property 'length' are incompatible.
+    Type 'number' is not assignable to type '1'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(32,31): error TS2344: Type '[number, ...string[]]' does not satisfy the constraint '[number, ...number[]]'.
+  Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(33,31): error TS2344: Type '[string, ...number[]]' does not satisfy the constraint '[number, ...number[]]'.
+  Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(34,31): error TS2344: Type '[number, number, string]' does not satisfy the constraint '[number, ...number[]]'.
+  Property '2' is incompatible with rest element type.
+    Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(35,31): error TS2344: Type '[number, number, number, string]' does not satisfy the constraint '[number, ...number[]]'.
+  Property '3' is incompatible with rest element type.
+    Type 'string' is not assignable to type 'number'.
+tests/cases/conformance/types/tuple/restTupleElements1.ts(59,4): error TS2345: Argument of type '[]' is not assignable to parameter of type '[{}, ...{}[]]'.
+  Property '0' is missing in type '[]'.
+
+
+==== tests/cases/conformance/types/tuple/restTupleElements1.ts (14 errors) ====
+    type T00 = [string?];
+    type T01 = [string, string?];
+    type T02 = [string?, string];  // Error
+                         ~~~~~~
+!!! error TS1257: A required element cannot follow an optional element.
+    type T03 = [...string[]];
+    type T04 = [...[...string[]]];
+    type T05 = [...[...[...string[]]]];
+    type T06 = [string, ...string[]];
+    type T07 = [...string[], string];  // Error
+                ~~~~~~~~~~~
+!!! error TS1256: A rest element must be last in a tuple type.
+    type T08 = [...string];  // Error
+                ~~~~~~~~~
+!!! error TS2574: A rest element type must be an array type.
+    type T09 = [...string?];  // Error
+                ~~~~~~~~~~
+!!! error TS2574: A rest element type must be an array type.
+                   ~~~~~~~
+!!! error TS8020: JSDoc types can only be used inside documentation comments.
+    type T10 = [string, ...[...string[]]];
+    type T11 = [string, ...[...[...string[]]]];
+    
+    type T15 = [boolean, number, ...string[]];
+    type L15 = T15["length"];  // number
+    
+    declare function assign<T, S extends T>(): void;
+    
+    assign<number[], [...number[]]>();
+    assign<number[], [number, ...number[]]>();
+    assign<[...number[]], number[]>();
+    
+    assign<[number, ...number[]], number[]>();  // Error
+                                  ~~~~~~~~
+!!! error TS2344: Type 'number[]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Property '0' is missing in type 'number[]'.
+    assign<[number, ...number[]], []>();  // Error
+                                  ~~
+!!! error TS2344: Type '[]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Property '0' is missing in type '[]'.
+    assign<[number, ...number[]], [number]>();
+    assign<[number, ...number[]], [number, number]>();
+    assign<[number, ...number[]], [number, number, ...number[]]>();
+    
+    assign<[number], [...number[]]>();  // Error
+                     ~~~~~~~~~~~~~
+!!! error TS2344: Type 'number[]' does not satisfy the constraint '[number]'.
+!!! error TS2344:   Property '0' is missing in type 'number[]'.
+    assign<[number], [number, ...number[]]>();  // Error
+                     ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type '[number, ...number[]]' does not satisfy the constraint '[number]'.
+!!! error TS2344:   Types of property 'length' are incompatible.
+!!! error TS2344:     Type 'number' is not assignable to type '1'.
+    
+    assign<[number, ...number[]], [number, ...string[]]>();  // Error
+                                  ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type '[number, ...string[]]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Type 'string' is not assignable to type 'number'.
+    assign<[number, ...number[]], [string, ...number[]]>();  // Error
+                                  ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type '[string, ...number[]]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Type 'string' is not assignable to type 'number'.
+    assign<[number, ...number[]], [number, number, string]>();  // Error
+                                  ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type '[number, number, string]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Property '2' is incompatible with rest element type.
+!!! error TS2344:     Type 'string' is not assignable to type 'number'.
+    assign<[number, ...number[]], [number, number, number, string]>();  // Error
+                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type '[number, number, number, string]' does not satisfy the constraint '[number, ...number[]]'.
+!!! error TS2344:   Property '3' is incompatible with rest element type.
+!!! error TS2344:     Type 'string' is not assignable to type 'number'.
+    
+    type T20 = [number, string, ...boolean[]];
+    
+    type T21 = T20[0];
+    type T22 = T20[0 | 1];
+    type T23 = T20[0 | 1 | 2];
+    type T24 = T20[0 | 1 | 2 | 3];
+    type T25 = T20[1 | 2 | 3];
+    type T26 = T20[2 | 3];
+    type T27 = T20[3];
+    type T28 = T20[number];
+    
+    declare const t: T20;
+    declare const x: number;
+    
+    let e0 = t[0];  // number
+    let e1 = t[1];  // string
+    let e2 = t[2];  // boolean
+    let e3 = t[3];  // boolean
+    let ex = t[x];  // number | string | boolean
+    
+    declare function f0<T, U>(x: [T, ...U[]]): [T, U];
+    
+    f0([]);  // Error
+       ~~
+!!! error TS2345: Argument of type '[]' is not assignable to parameter of type '[{}, ...{}[]]'.
+!!! error TS2345:   Property '0' is missing in type '[]'.
+    f0([1]);
+    f0([1, 2, 3]);
+    f0([1, "hello", true]);
+    
+    declare function f1(a: [(x: number) => number, ...((x: string) => number)[]]): void;
+    declare function f2(...a: [(x: number) => number, ...((x: string) => number)[]]): void;
+    
+    f1([x => x * 2, x => x.length, x => x.charCodeAt(0)]);
+    f2(x => x * 2, x => x.length, x => x.charCodeAt(0));
+    

tests/baselines/reference/restTupleElements1.js

@@ -0,0 +1,135 @@
+//// [restTupleElements1.ts]
+type T00 = [string?];
+type T01 = [string, string?];
+type T02 = [string?, string];  // Error
+type T03 = [...string[]];
+type T04 = [...[...string[]]];
+type T05 = [...[...[...string[]]]];
+type T06 = [string, ...string[]];
+type T07 = [...string[], string];  // Error
+type T08 = [...string];  // Error
+type T09 = [...string?];  // Error
+type T10 = [string, ...[...string[]]];
+type T11 = [string, ...[...[...string[]]]];
+
+type T15 = [boolean, number, ...string[]];
+type L15 = T15["length"];  // number
+
+declare function assign<T, S extends T>(): void;
+
+assign<number[], [...number[]]>();
+assign<number[], [number, ...number[]]>();
+assign<[...number[]], number[]>();
+
+assign<[number, ...number[]], number[]>();  // Error
+assign<[number, ...number[]], []>();  // Error
+assign<[number, ...number[]], [number]>();
+assign<[number, ...number[]], [number, number]>();
+assign<[number, ...number[]], [number, number, ...number[]]>();
+
+assign<[number], [...number[]]>();  // Error
+assign<[number], [number, ...number[]]>();  // Error
+
+assign<[number, ...number[]], [number, ...string[]]>();  // Error
+assign<[number, ...number[]], [string, ...number[]]>();  // Error
+assign<[number, ...number[]], [number, number, string]>();  // Error
+assign<[number, ...number[]], [number, number, number, string]>();  // Error
+
+type T20 = [number, string, ...boolean[]];
+
+type T21 = T20[0];
+type T22 = T20[0 | 1];
+type T23 = T20[0 | 1 | 2];
+type T24 = T20[0 | 1 | 2 | 3];
+type T25 = T20[1 | 2 | 3];
+type T26 = T20[2 | 3];
+type T27 = T20[3];
+type T28 = T20[number];
+
+declare const t: T20;
+declare const x: number;
+
+let e0 = t[0];  // number
+let e1 = t[1];  // string
+let e2 = t[2];  // boolean
+let e3 = t[3];  // boolean
+let ex = t[x];  // number | string | boolean
+
+declare function f0<T, U>(x: [T, ...U[]]): [T, U];
+
+f0([]);  // Error
+f0([1]);
+f0([1, 2, 3]);
+f0([1, "hello", true]);
+
+declare function f1(a: [(x: number) => number, ...((x: string) => number)[]]): void;
+declare function f2(...a: [(x: number) => number, ...((x: string) => number)[]]): void;
+
+f1([x => x * 2, x => x.length, x => x.charCodeAt(0)]);
+f2(x => x * 2, x => x.length, x => x.charCodeAt(0));
+
+
+//// [restTupleElements1.js]
+"use strict";
+assign();
+assign();
+assign();
+assign(); // Error
+assign(); // Error
+assign();
+assign();
+assign();
+assign(); // Error
+assign(); // Error
+assign(); // Error
+assign(); // Error
+assign(); // Error
+assign(); // Error
+var e0 = t[0]; // number
+var e1 = t[1]; // string
+var e2 = t[2]; // boolean
+var e3 = t[3]; // boolean
+var ex = t[x]; // number | string | boolean
+f0([]); // Error
+f0([1]);
+f0([1, 2, 3]);
+f0([1, "hello", true]);
+f1([function (x) { return x * 2; }, function (x) { return x.length; }, function (x) { return x.charCodeAt(0); }]);
+f2(function (x) { return x * 2; }, function (x) { return x.length; }, function (x) { return x.charCodeAt(0); });
+
+
+//// [restTupleElements1.d.ts]
+declare type T00 = [string?];
+declare type T01 = [string, string?];
+declare type T02 = [string?, string];
+declare type T03 = [...string[]];
+declare type T04 = [...[...string[]]];
+declare type T05 = [...[...[...string[]]]];
+declare type T06 = [string, ...string[]];
+declare type T07 = [...string[], string];
+declare type T08 = [...string];
+declare type T09 = [...?string];
+declare type T10 = [string, ...[...string[]]];
+declare type T11 = [string, ...[...[...string[]]]];
+declare type T15 = [boolean, number, ...string[]];
+declare type L15 = T15["length"];
+declare function assign<T, S extends T>(): void;
+declare type T20 = [number, string, ...boolean[]];
+declare type T21 = T20[0];
+declare type T22 = T20[0 | 1];
+declare type T23 = T20[0 | 1 | 2];
+declare type T24 = T20[0 | 1 | 2 | 3];
+declare type T25 = T20[1 | 2 | 3];
+declare type T26 = T20[2 | 3];
+declare type T27 = T20[3];
+declare type T28 = T20[number];
+declare const t: T20;
+declare const x: number;
+declare let e0: number;
+declare let e1: string;
+declare let e2: boolean;
+declare let e3: boolean;
+declare let ex: string | number | boolean;
+declare function f0<T, U>(x: [T, ...U[]]): [T, U];
+declare function f1(a: [(x: number) => number, ...((x: string) => number)[]]): void;
+declare function f2(...a: [(x: number) => number, ...((x: string) => number)[]]): void;

tests/baselines/reference/restTupleElements1.symbols

@@ -0,0 +1,217 @@
+=== tests/cases/conformance/types/tuple/restTupleElements1.ts ===
+type T00 = [string?];
+>T00 : Symbol(T00, Decl(restTupleElements1.ts, 0, 0))
+
+type T01 = [string, string?];
+>T01 : Symbol(T01, Decl(restTupleElements1.ts, 0, 21))
+
+type T02 = [string?, string];  // Error
+>T02 : Symbol(T02, Decl(restTupleElements1.ts, 1, 29))
+
+type T03 = [...string[]];
+>T03 : Symbol(T03, Decl(restTupleElements1.ts, 2, 29))
+
+type T04 = [...[...string[]]];
+>T04 : Symbol(T04, Decl(restTupleElements1.ts, 3, 25))
+
+type T05 = [...[...[...string[]]]];
+>T05 : Symbol(T05, Decl(restTupleElements1.ts, 4, 30))
+
+type T06 = [string, ...string[]];
+>T06 : Symbol(T06, Decl(restTupleElements1.ts, 5, 35))
+
+type T07 = [...string[], string];  // Error
+>T07 : Symbol(T07, Decl(restTupleElements1.ts, 6, 33))
+
+type T08 = [...string];  // Error
+>T08 : Symbol(T08, Decl(restTupleElements1.ts, 7, 33))
+
+type T09 = [...string?];  // Error
+>T09 : Symbol(T09, Decl(restTupleElements1.ts, 8, 23))
+
+type T10 = [string, ...[...string[]]];
+>T10 : Symbol(T10, Decl(restTupleElements1.ts, 9, 24))
+
+type T11 = [string, ...[...[...string[]]]];
+>T11 : Symbol(T11, Decl(restTupleElements1.ts, 10, 38))
+
+type T15 = [boolean, number, ...string[]];
+>T15 : Symbol(T15, Decl(restTupleElements1.ts, 11, 43))
+
+type L15 = T15["length"];  // number
+>L15 : Symbol(L15, Decl(restTupleElements1.ts, 13, 42))
+>T15 : Symbol(T15, Decl(restTupleElements1.ts, 11, 43))
+
+declare function assign<T, S extends T>(): void;
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+>T : Symbol(T, Decl(restTupleElements1.ts, 16, 24))
+>S : Symbol(S, Decl(restTupleElements1.ts, 16, 26))
+>T : Symbol(T, Decl(restTupleElements1.ts, 16, 24))
+
+assign<number[], [...number[]]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<number[], [number, ...number[]]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[...number[]], number[]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], number[]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], []>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number, number]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number, number, ...number[]]>();
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number], [...number[]]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number], [number, ...number[]]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number, ...string[]]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [string, ...number[]]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number, number, string]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+assign<[number, ...number[]], [number, number, number, string]>();  // Error
+>assign : Symbol(assign, Decl(restTupleElements1.ts, 14, 25))
+
+type T20 = [number, string, ...boolean[]];
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T21 = T20[0];
+>T21 : Symbol(T21, Decl(restTupleElements1.ts, 36, 42))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T22 = T20[0 | 1];
+>T22 : Symbol(T22, Decl(restTupleElements1.ts, 38, 18))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T23 = T20[0 | 1 | 2];
+>T23 : Symbol(T23, Decl(restTupleElements1.ts, 39, 22))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T24 = T20[0 | 1 | 2 | 3];
+>T24 : Symbol(T24, Decl(restTupleElements1.ts, 40, 26))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T25 = T20[1 | 2 | 3];
+>T25 : Symbol(T25, Decl(restTupleElements1.ts, 41, 30))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T26 = T20[2 | 3];
+>T26 : Symbol(T26, Decl(restTupleElements1.ts, 42, 26))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T27 = T20[3];
+>T27 : Symbol(T27, Decl(restTupleElements1.ts, 43, 22))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+type T28 = T20[number];
+>T28 : Symbol(T28, Decl(restTupleElements1.ts, 44, 18))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+declare const t: T20;
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+>T20 : Symbol(T20, Decl(restTupleElements1.ts, 34, 66))
+
+declare const x: number;
+>x : Symbol(x, Decl(restTupleElements1.ts, 48, 13))
+
+let e0 = t[0];  // number
+>e0 : Symbol(e0, Decl(restTupleElements1.ts, 50, 3))
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+>0 : Symbol(0)
+
+let e1 = t[1];  // string
+>e1 : Symbol(e1, Decl(restTupleElements1.ts, 51, 3))
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+>1 : Symbol(1)
+
+let e2 = t[2];  // boolean
+>e2 : Symbol(e2, Decl(restTupleElements1.ts, 52, 3))
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+
+let e3 = t[3];  // boolean
+>e3 : Symbol(e3, Decl(restTupleElements1.ts, 53, 3))
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+
+let ex = t[x];  // number | string | boolean
+>ex : Symbol(ex, Decl(restTupleElements1.ts, 54, 3))
+>t : Symbol(t, Decl(restTupleElements1.ts, 47, 13))
+>x : Symbol(x, Decl(restTupleElements1.ts, 48, 13))
+
+declare function f0<T, U>(x: [T, ...U[]]): [T, U];
+>f0 : Symbol(f0, Decl(restTupleElements1.ts, 54, 14))
+>T : Symbol(T, Decl(restTupleElements1.ts, 56, 20))
+>U : Symbol(U, Decl(restTupleElements1.ts, 56, 22))
+>x : Symbol(x, Decl(restTupleElements1.ts, 56, 26))
+>T : Symbol(T, Decl(restTupleElements1.ts, 56, 20))
+>U : Symbol(U, Decl(restTupleElements1.ts, 56, 22))
+>T : Symbol(T, Decl(restTupleElements1.ts, 56, 20))
+>U : Symbol(U, Decl(restTupleElements1.ts, 56, 22))
+
+f0([]);  // Error
+>f0 : Symbol(f0, Decl(restTupleElements1.ts, 54, 14))
+
+f0([1]);
+>f0 : Symbol(f0, Decl(restTupleElements1.ts, 54, 14))
+
+f0([1, 2, 3]);
+>f0 : Symbol(f0, Decl(restTupleElements1.ts, 54, 14))
+
+f0([1, "hello", true]);
+>f0 : Symbol(f0, Decl(restTupleElements1.ts, 54, 14))
+
+declare function f1(a: [(x: number) => number, ...((x: string) => number)[]]): void;
+>f1 : Symbol(f1, Decl(restTupleElements1.ts, 61, 23))
+>a : Symbol(a, Decl(restTupleElements1.ts, 63, 20))
+>x : Symbol(x, Decl(restTupleElements1.ts, 63, 25))
+>x : Symbol(x, Decl(restTupleElements1.ts, 63, 52))
+
+declare function f2(...a: [(x: number) => number, ...((x: string) => number)[]]): void;
+>f2 : Symbol(f2, Decl(restTupleElements1.ts, 63, 84))
+>a : Symbol(a, Decl(restTupleElements1.ts, 64, 20))
+>x : Symbol(x, Decl(restTupleElements1.ts, 64, 28))
+>x : Symbol(x, Decl(restTupleElements1.ts, 64, 55))
+
+f1([x => x * 2, x => x.length, x => x.charCodeAt(0)]);
+>f1 : Symbol(f1, Decl(restTupleElements1.ts, 61, 23))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 4))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 4))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 15))
+>x.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 15))
+>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 30))
+>x.charCodeAt : Symbol(String.charCodeAt, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 66, 30))
+>charCodeAt : Symbol(String.charCodeAt, Decl(lib.es5.d.ts, --, --))
+
+f2(x => x * 2, x => x.length, x => x.charCodeAt(0));
+>f2 : Symbol(f2, Decl(restTupleElements1.ts, 63, 84))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 3))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 3))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 14))
+>x.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 14))
+>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 29))
+>x.charCodeAt : Symbol(String.charCodeAt, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(restTupleElements1.ts, 67, 29))
+>charCodeAt : Symbol(String.charCodeAt, Decl(lib.es5.d.ts, --, --))
+

tests/baselines/reference/restTupleElements1.types

@@ -0,0 +1,270 @@
+=== tests/cases/conformance/types/tuple/restTupleElements1.ts ===
+type T00 = [string?];
+>T00 : [(string | undefined)?]
+
+type T01 = [string, string?];
+>T01 : [string, (string | undefined)?]
+
+type T02 = [string?, string];  // Error
+>T02 : [string | undefined, string]
+
+type T03 = [...string[]];
+>T03 : string[]
+
+type T04 = [...[...string[]]];
+>T04 : string[]
+
+type T05 = [...[...[...string[]]]];
+>T05 : string[]
+
+type T06 = [string, ...string[]];
+>T06 : [string, ...string[]]
+
+type T07 = [...string[], string];  // Error
+>T07 : [string[], string]
+
+type T08 = [...string];  // Error
+>T08 : string[]
+
+type T09 = [...string?];  // Error
+>T09 : (string | null)[]
+
+type T10 = [string, ...[...string[]]];
+>T10 : [string, ...string[]]
+
+type T11 = [string, ...[...[...string[]]]];
+>T11 : [string, ...string[]]
+
+type T15 = [boolean, number, ...string[]];
+>T15 : [boolean, number, ...string[]]
+
+type L15 = T15["length"];  // number
+>L15 : number
+>T15 : [boolean, number, ...string[]]
+
+declare function assign<T, S extends T>(): void;
+>assign : <T, S extends T>() => void
+>T : T
+>S : S
+>T : T
+
+assign<number[], [...number[]]>();
+>assign<number[], [...number[]]>() : void
+>assign : <T, S extends T>() => void
+
+assign<number[], [number, ...number[]]>();
+>assign<number[], [number, ...number[]]>() : void
+>assign : <T, S extends T>() => void
+
+assign<[...number[]], number[]>();
+>assign<[...number[]], number[]>() : void
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], number[]>();  // Error
+>assign<[number, ...number[]], number[]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], []>();  // Error
+>assign<[number, ...number[]], []>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number]>();
+>assign<[number, ...number[]], [number]>() : void
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number, number]>();
+>assign<[number, ...number[]], [number, number]>() : void
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number, number, ...number[]]>();
+>assign<[number, ...number[]], [number, number, ...number[]]>() : void
+>assign : <T, S extends T>() => void
+
+assign<[number], [...number[]]>();  // Error
+>assign<[number], [...number[]]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number], [number, ...number[]]>();  // Error
+>assign<[number], [number, ...number[]]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number, ...string[]]>();  // Error
+>assign<[number, ...number[]], [number, ...string[]]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [string, ...number[]]>();  // Error
+>assign<[number, ...number[]], [string, ...number[]]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number, number, string]>();  // Error
+>assign<[number, ...number[]], [number, number, string]>() : any
+>assign : <T, S extends T>() => void
+
+assign<[number, ...number[]], [number, number, number, string]>();  // Error
+>assign<[number, ...number[]], [number, number, number, string]>() : any
+>assign : <T, S extends T>() => void
+
+type T20 = [number, string, ...boolean[]];
+>T20 : [number, string, ...boolean[]]
+
+type T21 = T20[0];
+>T21 : number
+>T20 : [number, string, ...boolean[]]
+
+type T22 = T20[0 | 1];
+>T22 : string | number
+>T20 : [number, string, ...boolean[]]
+
+type T23 = T20[0 | 1 | 2];
+>T23 : string | number | boolean
+>T20 : [number, string, ...boolean[]]
+
+type T24 = T20[0 | 1 | 2 | 3];
+>T24 : string | number | boolean
+>T20 : [number, string, ...boolean[]]
+
+type T25 = T20[1 | 2 | 3];
+>T25 : string | boolean
+>T20 : [number, string, ...boolean[]]
+
+type T26 = T20[2 | 3];
+>T26 : boolean
+>T20 : [number, string, ...boolean[]]
+
+type T27 = T20[3];
+>T27 : boolean
+>T20 : [number, string, ...boolean[]]
+
+type T28 = T20[number];
+>T28 : string | number | boolean
+>T20 : [number, string, ...boolean[]]
+
+declare const t: T20;
+>t : [number, string, ...boolean[]]
+>T20 : [number, string, ...boolean[]]
+
+declare const x: number;
+>x : number
+
+let e0 = t[0];  // number
+>e0 : number
+>t[0] : number
+>t : [number, string, ...boolean[]]
+>0 : 0
+
+let e1 = t[1];  // string
+>e1 : string
+>t[1] : string
+>t : [number, string, ...boolean[]]
+>1 : 1
+
+let e2 = t[2];  // boolean
+>e2 : boolean
+>t[2] : boolean
+>t : [number, string, ...boolean[]]
+>2 : 2
+
+let e3 = t[3];  // boolean
+>e3 : boolean
+>t[3] : boolean
+>t : [number, string, ...boolean[]]
+>3 : 3
+
+let ex = t[x];  // number | string | boolean
+>ex : string | number | boolean
+>t[x] : string | number | boolean
+>t : [number, string, ...boolean[]]
+>x : number
+
+declare function f0<T, U>(x: [T, ...U[]]): [T, U];
+>f0 : <T, U>(x: [T, ...U[]]) => [T, U]
+>T : T
+>U : U
+>x : [T, ...U[]]
+>T : T
+>U : U
+>T : T
+>U : U
+
+f0([]);  // Error
+>f0([]) : any
+>f0 : <T, U>(x: [T, ...U[]]) => [T, U]
+>[] : never[]
+
+f0([1]);
+>f0([1]) : [number, {}]
+>f0 : <T, U>(x: [T, ...U[]]) => [T, U]
+>[1] : [number]
+>1 : 1
+
+f0([1, 2, 3]);
+>f0([1, 2, 3]) : [number, number]
+>f0 : <T, U>(x: [T, ...U[]]) => [T, U]
+>[1, 2, 3] : [number, number, number]
+>1 : 1
+>2 : 2
+>3 : 3
+
+f0([1, "hello", true]);
+>f0([1, "hello", true]) : [number, string | boolean]
+>f0 : <T, U>(x: [T, ...U[]]) => [T, U]
+>[1, "hello", true] : [number, string, true]
+>1 : 1
+>"hello" : "hello"
+>true : true
+
+declare function f1(a: [(x: number) => number, ...((x: string) => number)[]]): void;
+>f1 : (a: [(x: number) => number, ...((x: string) => number)[]]) => void
+>a : [(x: number) => number, ...((x: string) => number)[]]
+>x : number
+>x : string
+
+declare function f2(...a: [(x: number) => number, ...((x: string) => number)[]]): void;
+>f2 : (a_0: (x: number) => number, ...a_1: ((x: string) => number)[]) => void
+>a : [(x: number) => number, ...((x: string) => number)[]]
+>x : number
+>x : string
+
+f1([x => x * 2, x => x.length, x => x.charCodeAt(0)]);
+>f1([x => x * 2, x => x.length, x => x.charCodeAt(0)]) : void
+>f1 : (a: [(x: number) => number, ...((x: string) => number)[]]) => void
+>[x => x * 2, x => x.length, x => x.charCodeAt(0)] : [(x: number) => number, (x: string) => number, (x: string) => number]
+>x => x * 2 : (x: number) => number
+>x : number
+>x * 2 : number
+>x : number
+>2 : 2
+>x => x.length : (x: string) => number
+>x : string
+>x.length : number
+>x : string
+>length : number
+>x => x.charCodeAt(0) : (x: string) => number
+>x : string
+>x.charCodeAt(0) : number
+>x.charCodeAt : (index: number) => number
+>x : string
+>charCodeAt : (index: number) => number
+>0 : 0
+
+f2(x => x * 2, x => x.length, x => x.charCodeAt(0));
+>f2(x => x * 2, x => x.length, x => x.charCodeAt(0)) : void
+>f2 : (a_0: (x: number) => number, ...a_1: ((x: string) => number)[]) => void
+>x => x * 2 : (x: number) => number
+>x : number
+>x * 2 : number
+>x : number
+>2 : 2
+>x => x.length : (x: string) => number
+>x : string
+>x.length : number
+>x : string
+>length : number
+>x => x.charCodeAt(0) : (x: string) => number
+>x : string
+>x.charCodeAt(0) : number
+>x.charCodeAt : (index: number) => number
+>x : string
+>charCodeAt : (index: number) => number
+>0 : 0
+