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Merge pull request #5906 from weswigham/this-type-guards

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This type predicates for type guards
This commit is contained in:
Wesley Wigham
2015-12-09 17:22:39 -08:00
parent 6e06752c05 8e586943a1
commit 58400ed771
30 changed files with 2943 additions and 178 deletions
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src/compiler/binder.ts
+13 -1
View File
@@ -1189,7 +1189,8 @@ namespace ts {
case SyntaxKind.ThisType:
seenThisKeyword = true;
return;
case SyntaxKind.TypePredicate:
return checkTypePredicate(node as TypePredicateNode);
case SyntaxKind.TypeParameter:
return declareSymbolAndAddToSymbolTable(<Declaration>node, SymbolFlags.TypeParameter, SymbolFlags.TypeParameterExcludes);
case SyntaxKind.Parameter:
@@ -1275,6 +1276,17 @@ namespace ts {
}
}
function checkTypePredicate(node: TypePredicateNode) {
const { parameterName, type } = node;
if (parameterName && parameterName.kind === SyntaxKind.Identifier) {
checkStrictModeIdentifier(parameterName as Identifier);
}
if (parameterName && parameterName.kind === SyntaxKind.ThisType) {
seenThisKeyword = true;
}
bind(type);
}
function bindSourceFileIfExternalModule() {
setExportContextFlag(file);
if (isExternalModule(file)) {
src/compiler/checker.ts
+241 -121
View File
@@ -124,8 +124,8 @@ namespace ts {
const noConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const anySignature = createSignature(undefined, undefined, emptyArray, anyType, undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const unknownSignature = createSignature(undefined, undefined, emptyArray, unknownType, undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const anySignature = createSignature(undefined, undefined, emptyArray, anyType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const unknownSignature = createSignature(undefined, undefined, emptyArray, unknownType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const globals: SymbolTable = {};
@@ -1743,10 +1743,16 @@ namespace ts {
function writeType(type: Type, flags: TypeFormatFlags) {
// Write undefined/null type as any
if (type.flags & TypeFlags.Intrinsic) {
// Special handling for unknown / resolving types, they should show up as any and not unknown or __resolving
writer.writeKeyword(!(globalFlags & TypeFormatFlags.WriteOwnNameForAnyLike) && isTypeAny(type)
? "any"
: (<IntrinsicType>type).intrinsicName);
if (type.flags & TypeFlags.PredicateType) {
buildTypePredicateDisplay(writer, (type as PredicateType).predicate);
buildTypeDisplay((type as PredicateType).predicate.type, writer, enclosingDeclaration, flags, symbolStack);
}
else {
// Special handling for unknown / resolving types, they should show up as any and not unknown or __resolving
writer.writeKeyword(!(globalFlags & TypeFormatFlags.WriteOwnNameForAnyLike) && isTypeAny(type)
? "any"
: (<IntrinsicType>type).intrinsicName);
}
}
else if (type.flags & TypeFlags.ThisType) {
if (inObjectTypeLiteral) {
@@ -2116,6 +2122,18 @@ namespace ts {
writePunctuation(writer, SyntaxKind.CloseParenToken);
}
function buildTypePredicateDisplay(writer: SymbolWriter, predicate: TypePredicate) {
if (isIdentifierTypePredicate(predicate)) {
writer.writeParameter(predicate.parameterName);
}
else {
writeKeyword(writer, SyntaxKind.ThisKeyword);
}
writeSpace(writer);
writeKeyword(writer, SyntaxKind.IsKeyword);
writeSpace(writer);
}
function buildReturnTypeDisplay(signature: Signature, writer: SymbolWriter, enclosingDeclaration?: Node, flags?: TypeFormatFlags, symbolStack?: Symbol[]) {
if (flags & TypeFormatFlags.WriteArrowStyleSignature) {
writeSpace(writer);
@@ -2126,17 +2144,7 @@ namespace ts {
}
writeSpace(writer);
let returnType: Type;
if (signature.typePredicate) {
writer.writeParameter(signature.typePredicate.parameterName);
writeSpace(writer);
writeKeyword(writer, SyntaxKind.IsKeyword);
writeSpace(writer);
returnType = signature.typePredicate.type;
}
else {
returnType = getReturnTypeOfSignature(signature);
}
const returnType = getReturnTypeOfSignature(signature);
buildTypeDisplay(returnType, writer, enclosingDeclaration, flags, symbolStack);
}
@@ -2693,7 +2701,13 @@ namespace ts {
// During a normal type check we'll never get to here with a property assignment (the check of the containing
// object literal uses a different path). We exclude widening only so that language services and type verification
// tools see the actual type.
return declaration.kind !== SyntaxKind.PropertyAssignment ? getWidenedType(type) : type;
if (declaration.kind === SyntaxKind.PropertyAssignment) {
return type;
}
if (type.flags & TypeFlags.PredicateType && (declaration.kind === SyntaxKind.PropertyDeclaration || declaration.kind === SyntaxKind.PropertySignature)) {
return type;
}
return getWidenedType(type);
}
// Rest parameters default to type any[], other parameters default to type any
@@ -3427,13 +3441,12 @@ namespace ts {
}
function createSignature(declaration: SignatureDeclaration, typeParameters: TypeParameter[], parameters: Symbol[],
resolvedReturnType: Type, typePredicate: TypePredicate, minArgumentCount: number, hasRestParameter: boolean, hasStringLiterals: boolean): Signature {
resolvedReturnType: Type, minArgumentCount: number, hasRestParameter: boolean, hasStringLiterals: boolean): Signature {
const sig = new Signature(checker);
sig.declaration = declaration;
sig.typeParameters = typeParameters;
sig.parameters = parameters;
sig.resolvedReturnType = resolvedReturnType;
sig.typePredicate = typePredicate;
sig.minArgumentCount = minArgumentCount;
sig.hasRestParameter = hasRestParameter;
sig.hasStringLiterals = hasStringLiterals;
@@ -3441,7 +3454,7 @@ namespace ts {
}
function cloneSignature(sig: Signature): Signature {
return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType, sig.typePredicate,
return createSignature(sig.declaration, sig.typeParameters, sig.parameters, sig.resolvedReturnType,
sig.minArgumentCount, sig.hasRestParameter, sig.hasStringLiterals);
}
@@ -3449,7 +3462,7 @@ namespace ts {
const baseConstructorType = getBaseConstructorTypeOfClass(classType);
const baseSignatures = getSignaturesOfType(baseConstructorType, SignatureKind.Construct);
if (baseSignatures.length === 0) {
return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, undefined, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
return [createSignature(undefined, classType.localTypeParameters, emptyArray, classType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false)];
}
const baseTypeNode = getBaseTypeNodeOfClass(classType);
const typeArguments = map(baseTypeNode.typeArguments, getTypeFromTypeNode);
@@ -3915,6 +3928,24 @@ namespace ts {
return false;
}
function createTypePredicateFromTypePredicateNode(node: TypePredicateNode): IdentifierTypePredicate | ThisTypePredicate {
if (node.parameterName.kind === SyntaxKind.Identifier) {
const parameterName = node.parameterName as Identifier;
return {
kind: TypePredicateKind.Identifier,
parameterName: parameterName ? parameterName.text : undefined,
parameterIndex: parameterName ? getTypePredicateParameterIndex((node.parent as SignatureDeclaration).parameters, parameterName) : undefined,
type: getTypeFromTypeNode(node.type)
} as IdentifierTypePredicate;
}
else {
return {
kind: TypePredicateKind.This,
type: getTypeFromTypeNode(node.type)
} as ThisTypePredicate;
}
}
function getSignatureFromDeclaration(declaration: SignatureDeclaration): Signature {
const links = getNodeLinks(declaration);
if (!links.resolvedSignature) {
@@ -3955,20 +3986,11 @@ namespace ts {
}
let returnType: Type;
let typePredicate: TypePredicate;
if (classType) {
returnType = classType;
}
else if (declaration.type) {
returnType = getTypeFromTypeNode(declaration.type);
if (declaration.type.kind === SyntaxKind.TypePredicate) {
const typePredicateNode = <TypePredicateNode>declaration.type;
typePredicate = {
parameterName: typePredicateNode.parameterName ? typePredicateNode.parameterName.text : undefined,
parameterIndex: typePredicateNode.parameterName ? getTypePredicateParameterIndex(declaration.parameters, typePredicateNode.parameterName) : undefined,
type: getTypeFromTypeNode(typePredicateNode.type)
};
}
}
else {
// TypeScript 1.0 spec (April 2014):
@@ -3983,8 +4005,7 @@ namespace ts {
}
}
links.resolvedSignature = createSignature(declaration, typeParameters, parameters, returnType, typePredicate,
minArgumentCount, hasRestParameter(declaration), hasStringLiterals);
links.resolvedSignature = createSignature(declaration, typeParameters, parameters, returnType, minArgumentCount, hasRestParameter(declaration), hasStringLiterals);
}
return links.resolvedSignature;
}
@@ -4643,6 +4664,25 @@ namespace ts {
return links.resolvedType;
}
function getPredicateType(node: TypePredicateNode): Type {
return createPredicateType(getSymbolOfNode(node), createTypePredicateFromTypePredicateNode(node));
}
function createPredicateType(symbol: Symbol, predicate: ThisTypePredicate | IdentifierTypePredicate) {
const type = createType(TypeFlags.Boolean | TypeFlags.PredicateType) as PredicateType;
type.symbol = symbol;
type.predicate = predicate;
return type;
}
function getTypeFromPredicateTypeNode(node: TypePredicateNode): Type {
const links = getNodeLinks(node);
if (!links.resolvedType) {
links.resolvedType = getPredicateType(node);
}
return links.resolvedType;
}
function getTypeFromTypeNode(node: TypeNode): Type {
switch (node.kind) {
case SyntaxKind.AnyKeyword:
@@ -4664,7 +4704,7 @@ namespace ts {
case SyntaxKind.TypeReference:
return getTypeFromTypeReference(<TypeReferenceNode>node);
case SyntaxKind.TypePredicate:
return booleanType;
return getTypeFromPredicateTypeNode(<TypePredicateNode>node);
case SyntaxKind.ExpressionWithTypeArguments:
return getTypeFromTypeReference(<ExpressionWithTypeArguments>node);
case SyntaxKind.TypeQuery:
@@ -4787,24 +4827,32 @@ namespace ts {
return result;
}
function cloneTypePredicate(predicate: TypePredicate, mapper: TypeMapper): ThisTypePredicate | IdentifierTypePredicate {
if (isIdentifierTypePredicate(predicate)) {
return {
kind: TypePredicateKind.Identifier,
parameterName: predicate.parameterName,
parameterIndex: predicate.parameterIndex,
type: instantiateType(predicate.type, mapper)
} as IdentifierTypePredicate;
}
else {
return {
kind: TypePredicateKind.This,
type: instantiateType(predicate.type, mapper)
} as ThisTypePredicate;
}
}
function instantiateSignature(signature: Signature, mapper: TypeMapper, eraseTypeParameters?: boolean): Signature {
let freshTypeParameters: TypeParameter[];
let freshTypePredicate: TypePredicate;
if (signature.typeParameters && !eraseTypeParameters) {
freshTypeParameters = instantiateList(signature.typeParameters, mapper, instantiateTypeParameter);
mapper = combineTypeMappers(createTypeMapper(signature.typeParameters, freshTypeParameters), mapper);
}
if (signature.typePredicate) {
freshTypePredicate = {
parameterName: signature.typePredicate.parameterName,
parameterIndex: signature.typePredicate.parameterIndex,
type: instantiateType(signature.typePredicate.type, mapper)
};
}
const result = createSignature(signature.declaration, freshTypeParameters,
instantiateList(signature.parameters, mapper, instantiateSymbol),
instantiateType(signature.resolvedReturnType, mapper),
freshTypePredicate,
signature.minArgumentCount, signature.hasRestParameter, signature.hasStringLiterals);
result.target = signature;
result.mapper = mapper;
@@ -4874,6 +4922,10 @@ namespace ts {
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(instantiateList((<IntersectionType>type).types, mapper, instantiateType));
}
if (type.flags & TypeFlags.PredicateType) {
const predicate = (type as PredicateType).predicate;
return createPredicateType(type.symbol, cloneTypePredicate(predicate, mapper));
}
}
return type;
}
@@ -5045,6 +5097,36 @@ namespace ts {
if (isTypeAny(source)) return Ternary.True;
if (source === numberType && target.flags & TypeFlags.Enum) return Ternary.True;
}
if (source.flags & TypeFlags.Boolean && target.flags & TypeFlags.Boolean) {
if (source.flags & TypeFlags.PredicateType && target.flags & TypeFlags.PredicateType) {
const sourcePredicate = source as PredicateType;
const targetPredicate = target as PredicateType;
if (sourcePredicate.predicate.kind !== targetPredicate.predicate.kind) {
if (reportErrors) {
reportError(Diagnostics.A_this_based_type_guard_is_not_compatible_with_a_parameter_based_type_guard);
reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
}
return Ternary.False;
}
if (sourcePredicate.predicate.kind === TypePredicateKind.Identifier) {
const sourceIdentifierPredicate = sourcePredicate.predicate as IdentifierTypePredicate;
const targetIdentifierPredicate = targetPredicate.predicate as IdentifierTypePredicate;
if (sourceIdentifierPredicate.parameterIndex !== targetIdentifierPredicate.parameterIndex) {
if (reportErrors) {
reportError(Diagnostics.Parameter_0_is_not_in_the_same_position_as_parameter_1, sourceIdentifierPredicate.parameterName, targetIdentifierPredicate.parameterName);
reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
}
return Ternary.False;
}
}
const related = isRelatedTo(sourcePredicate.predicate.type, targetPredicate.predicate.type, reportErrors, headMessage);
if (related === Ternary.False && reportErrors) {
reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1, typeToString(source), typeToString(target));
}
return related;
}
return Ternary.True;
}
if (source.flags & TypeFlags.FreshObjectLiteral) {
if (hasExcessProperties(<FreshObjectLiteralType>source, target, reportErrors)) {
@@ -5610,46 +5692,19 @@ namespace ts {
result &= related;
}
if (source.typePredicate && target.typePredicate) {
const hasDifferentParameterIndex = source.typePredicate.parameterIndex !== target.typePredicate.parameterIndex;
let hasDifferentTypes: boolean;
if (hasDifferentParameterIndex ||
(hasDifferentTypes = !isTypeIdenticalTo(source.typePredicate.type, target.typePredicate.type))) {
const targetReturnType = getReturnTypeOfSignature(target);
if (targetReturnType === voidType) return result;
const sourceReturnType = getReturnTypeOfSignature(source);
// The follow block preserves old behavior forbidding boolean returning functions from being assignable to type guard returning functions
if (targetReturnType.flags & TypeFlags.PredicateType && (targetReturnType as PredicateType).predicate.kind === TypePredicateKind.Identifier) {
if (!(sourceReturnType.flags & TypeFlags.PredicateType)) {
if (reportErrors) {
const sourceParamText = source.typePredicate.parameterName;
const targetParamText = target.typePredicate.parameterName;
const sourceTypeText = typeToString(source.typePredicate.type);
const targetTypeText = typeToString(target.typePredicate.type);
if (hasDifferentParameterIndex) {
reportError(Diagnostics.Parameter_0_is_not_in_the_same_position_as_parameter_1,
sourceParamText,
targetParamText);
}
else if (hasDifferentTypes) {
reportError(Diagnostics.Type_0_is_not_assignable_to_type_1,
sourceTypeText,
targetTypeText);
}
reportError(Diagnostics.Type_predicate_0_is_not_assignable_to_1,
`${sourceParamText} is ${sourceTypeText}`,
`${targetParamText} is ${targetTypeText}`);
reportError(Diagnostics.Signature_0_must_have_a_type_predicate, signatureToString(source));
}
return Ternary.False;
}
}
else if (!source.typePredicate && target.typePredicate) {
if (reportErrors) {
reportError(Diagnostics.Signature_0_must_have_a_type_predicate, signatureToString(source));
}
return Ternary.False;
}
const targetReturnType = getReturnTypeOfSignature(target);
if (targetReturnType === voidType) return result;
const sourceReturnType = getReturnTypeOfSignature(source);
return result & isRelatedTo(sourceReturnType, targetReturnType, reportErrors);
}
@@ -5986,6 +6041,9 @@ namespace ts {
if (type.flags & (TypeFlags.Undefined | TypeFlags.Null)) {
return anyType;
}
if (type.flags & TypeFlags.PredicateType) {
return booleanType;
}
if (type.flags & TypeFlags.ObjectLiteral) {
return getWidenedTypeOfObjectLiteral(type);
}
@@ -6209,6 +6267,11 @@ namespace ts {
inferFromTypes(sourceTypes[i], targetTypes[i]);
}
}
else if (source.flags & TypeFlags.PredicateType && target.flags & TypeFlags.PredicateType) {
if ((source as PredicateType).predicate.kind === (target as PredicateType).predicate.kind) {
inferFromTypes((source as PredicateType).predicate.type, (target as PredicateType).predicate.type);
}
}
else if (source.flags & TypeFlags.Tuple && target.flags & TypeFlags.Tuple && (<TupleType>source).elementTypes.length === (<TupleType>target).elementTypes.length) {
// If source and target are tuples of the same size, infer from element types
const sourceTypes = (<TupleType>source).elementTypes;
@@ -6304,17 +6367,7 @@ namespace ts {
function inferFromSignature(source: Signature, target: Signature) {
forEachMatchingParameterType(source, target, inferFromTypes);
if (source.typePredicate && target.typePredicate) {
if (target.typePredicate.parameterIndex === source.typePredicate.parameterIndex) {
// Return types from type predicates are treated as booleans. In order to infer types
// from type predicates we would need to infer using the type within the type predicate
// (i.e. 'Foo' from 'x is Foo').
inferFromTypes(source.typePredicate.type, target.typePredicate.type);
}
}
else {
inferFromTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
}
inferFromTypes(getReturnTypeOfSignature(source), getReturnTypeOfSignature(target));
}
function inferFromIndexTypes(source: Type, target: Type, sourceKind: IndexKind, targetKind: IndexKind) {
@@ -6453,10 +6506,7 @@ namespace ts {
function isAssignedInBinaryExpression(node: BinaryExpression) {
if (node.operatorToken.kind >= SyntaxKind.FirstAssignment && node.operatorToken.kind <= SyntaxKind.LastAssignment) {
let n = node.left;
while (n.kind === SyntaxKind.ParenthesizedExpression) {
n = (<ParenthesizedExpression>n).expression;
}
const n = skipParenthesizedNodes(node.left);
if (n.kind === SyntaxKind.Identifier && getResolvedSymbol(<Identifier>n) === symbol) {
return true;
}
@@ -6712,20 +6762,20 @@ namespace ts {
}
if (targetType) {
if (!assumeTrue) {
if (type.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>type).types, t => !isTypeSubtypeOf(t, targetType)));
}
return type;
}
return getNarrowedType(type, targetType);
return getNarrowedType(type, targetType, assumeTrue);
}
return type;
}
function getNarrowedType(originalType: Type, narrowedTypeCandidate: Type) {
function getNarrowedType(originalType: Type, narrowedTypeCandidate: Type, assumeTrue: boolean) {
if (!assumeTrue) {
if (originalType.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>originalType).types, t => !isTypeSubtypeOf(t, narrowedTypeCandidate)));
}
return originalType;
}
// If the current type is a union type, remove all constituents that aren't assignable to target. If that produces
// 0 candidates, fall back to the assignability check
if (originalType.flags & TypeFlags.Union) {
@@ -6748,22 +6798,59 @@ namespace ts {
return type;
}
const signature = getResolvedSignature(expr);
const predicateType = getReturnTypeOfSignature(signature);
if (signature.typePredicate &&
expr.arguments[signature.typePredicate.parameterIndex] &&
getSymbolAtLocation(expr.arguments[signature.typePredicate.parameterIndex]) === symbol) {
if (!assumeTrue) {
if (type.flags & TypeFlags.Union) {
return getUnionType(filter((<UnionType>type).types, t => !isTypeSubtypeOf(t, signature.typePredicate.type)));
}
return type;
if (!predicateType || !(predicateType.flags & TypeFlags.PredicateType)) {
return type;
}
const predicate = (predicateType as PredicateType).predicate;
if (isIdentifierTypePredicate(predicate)) {
const callExpression = expr as CallExpression;
if (callExpression.arguments[predicate.parameterIndex] &&
getSymbolAtTypePredicatePosition(callExpression.arguments[predicate.parameterIndex]) === symbol) {
return getNarrowedType(type, predicate.type, assumeTrue);
}
return getNarrowedType(type, signature.typePredicate.type);
}
else {
const expression = skipParenthesizedNodes(expr.expression);
return narrowTypeByThisTypePredicate(type, predicate, expression, assumeTrue);
}
return type;
}
function narrowTypeByTypePredicateMember(type: Type, expr: ElementAccessExpression | PropertyAccessExpression, assumeTrue: boolean): Type {
if (type.flags & TypeFlags.Any) {
return type;
}
const memberType = getTypeOfExpression(expr);
if (!(memberType.flags & TypeFlags.PredicateType)) {
return type;
}
return narrowTypeByThisTypePredicate(type, (memberType as PredicateType).predicate as ThisTypePredicate, expr, assumeTrue);
}
function narrowTypeByThisTypePredicate(type: Type, predicate: ThisTypePredicate, expression: Expression, assumeTrue: boolean): Type {
if (expression.kind === SyntaxKind.ElementAccessExpression || expression.kind === SyntaxKind.PropertyAccessExpression) {
const accessExpression = expression as ElementAccessExpression | PropertyAccessExpression;
const possibleIdentifier = skipParenthesizedNodes(accessExpression.expression);
if (possibleIdentifier.kind === SyntaxKind.Identifier && getSymbolAtTypePredicatePosition(possibleIdentifier) === symbol) {
return getNarrowedType(type, predicate.type, assumeTrue);
}
}
return type;
}
function getSymbolAtTypePredicatePosition(expr: Expression): Symbol {
expr = skipParenthesizedNodes(expr);
switch (expr.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.PropertyAccessExpression:
case SyntaxKind.QualifiedName:
return getSymbolOfEntityNameOrPropertyAccessExpression(expr as Node as (EntityName | PropertyAccessExpression));
}
}
// Narrow the given type based on the given expression having the assumed boolean value. The returned type
// will be a subtype or the same type as the argument.
function narrowType(type: Type, expr: Expression, assumeTrue: boolean): Type {
@@ -6792,11 +6879,21 @@ namespace ts {
return narrowType(type, (<PrefixUnaryExpression>expr).operand, !assumeTrue);
}
break;
case SyntaxKind.ElementAccessExpression:
case SyntaxKind.PropertyAccessExpression:
return narrowTypeByTypePredicateMember(type, expr as (ElementAccessExpression | PropertyAccessExpression), assumeTrue);
}
return type;
}
}
function skipParenthesizedNodes(expression: Expression): Expression {
while (expression.kind === SyntaxKind.ParenthesizedExpression) {
expression = (expression as ParenthesizedExpression).expression;
}
return expression;
}
function checkIdentifier(node: Identifier): Type {
const symbol = getResolvedSymbol(node);
@@ -10985,7 +11082,7 @@ namespace ts {
return -1;
}
function isInLegalTypePredicatePosition(node: Node): boolean {
function isInLegalParameterTypePredicatePosition(node: Node): boolean {
switch (node.parent.kind) {
case SyntaxKind.ArrowFunction:
case SyntaxKind.CallSignature:
@@ -10999,6 +11096,19 @@ namespace ts {
return false;
}
function isInLegalThisTypePredicatePosition(node: Node): boolean {
if (isInLegalParameterTypePredicatePosition(node)) {
return true;
}
switch (node.parent.kind) {
case SyntaxKind.PropertyDeclaration:
case SyntaxKind.PropertySignature:
case SyntaxKind.GetAccessor:
return node === (node.parent as (PropertyDeclaration | GetAccessorDeclaration | PropertySignature)).type;
}
return false;
}
function checkSignatureDeclaration(node: SignatureDeclaration) {
// Grammar checking
if (node.kind === SyntaxKind.IndexSignature) {
@@ -11017,9 +11127,14 @@ namespace ts {
if (node.type) {
if (node.type.kind === SyntaxKind.TypePredicate) {
const typePredicate = getSignatureFromDeclaration(node).typePredicate;
const typePredicateNode = <TypePredicateNode>node.type;
if (isInLegalTypePredicatePosition(typePredicateNode)) {
const returnType = getReturnTypeOfSignature(getSignatureFromDeclaration(node));
if (!returnType || !(returnType.flags & TypeFlags.PredicateType)) {
return;
}
const typePredicate = (returnType as PredicateType).predicate;
const typePredicateNode = node.type as TypePredicateNode;
checkSourceElement(typePredicateNode);
if (isIdentifierTypePredicate(typePredicate)) {
if (typePredicate.parameterIndex >= 0) {
if (node.parameters[typePredicate.parameterIndex].dotDotDotToken) {
error(typePredicateNode.parameterName,
@@ -11067,10 +11182,6 @@ namespace ts {
}
}
}
else {
error(typePredicateNode,
Diagnostics.A_type_predicate_is_only_allowed_in_return_type_position_for_functions_and_methods);
}
}
else {
checkSourceElement(node.type);
@@ -13027,7 +13138,7 @@ namespace ts {
error(node.expression, Diagnostics.Return_type_of_constructor_signature_must_be_assignable_to_the_instance_type_of_the_class);
}
}
else if (func.type || isGetAccessorWithAnnotatatedSetAccessor(func) || signature.typePredicate) {
else if (func.type || isGetAccessorWithAnnotatatedSetAccessor(func) || returnType.flags & TypeFlags.PredicateType) {
if (isAsyncFunctionLike(func)) {
const promisedType = getPromisedType(returnType);
const awaitedType = checkAwaitedType(exprType, node.expression, Diagnostics.Return_expression_in_async_function_does_not_have_a_valid_callable_then_member);
@@ -14218,9 +14329,18 @@ namespace ts {
}
function checkTypePredicate(node: TypePredicateNode) {
if (!isInLegalTypePredicatePosition(node)) {
const { parameterName } = node;
if (parameterName.kind === SyntaxKind.Identifier && !isInLegalParameterTypePredicatePosition(node)) {
error(node, Diagnostics.A_type_predicate_is_only_allowed_in_return_type_position_for_functions_and_methods);
}
else if (parameterName.kind === SyntaxKind.ThisType) {
if (!isInLegalThisTypePredicatePosition(node)) {
error(node, Diagnostics.A_this_based_type_predicate_is_only_allowed_within_a_class_or_interface_s_members_get_accessors_or_return_type_positions_for_functions_and_methods);
}
else {
getTypeFromThisTypeNode(parameterName as ThisTypeNode);
}
}
}
function checkSourceElement(node: Node): void {
src/compiler/diagnosticMessages.json
+8
View File
@@ -1647,6 +1647,14 @@
"category": "Error",
"code": 2517
},
"A 'this'-based type guard is not compatible with a parameter-based type guard.": {
"category": "Error",
"code": 2518
},
"A 'this'-based type predicate is only allowed within a class or interface's members, get accessors, or return type positions for functions and methods.": {
"category": "Error",
"code": 2519
},
"Duplicate identifier '{0}'. Compiler uses declaration '{1}' to support async functions.": {
"category": "Error",
"code": 2520
src/compiler/parser.ts
+20 -9
View File
@@ -1963,11 +1963,7 @@ namespace ts {
function parseTypeReferenceOrTypePredicate(): TypeReferenceNode | TypePredicateNode {
const typeName = parseEntityName(/*allowReservedWords*/ false, Diagnostics.Type_expected);
if (typeName.kind === SyntaxKind.Identifier && token === SyntaxKind.IsKeyword && !scanner.hasPrecedingLineBreak()) {
nextToken();
const node = <TypePredicateNode>createNode(SyntaxKind.TypePredicate, typeName.pos);
node.parameterName = <Identifier>typeName;
node.type = parseType();
return finishNode(node);
return parseTypePredicate(typeName as Identifier);
}
const node = <TypeReferenceNode>createNode(SyntaxKind.TypeReference, typeName.pos);
node.typeName = typeName;
@@ -1977,8 +1973,16 @@ namespace ts {
return finishNode(node);
}
function parseThisTypeNode(): TypeNode {
const node = <TypeNode>createNode(SyntaxKind.ThisType);
function parseTypePredicate(lhs: Identifier | ThisTypeNode): TypePredicateNode {
nextToken();
const node = createNode(SyntaxKind.TypePredicate, lhs.pos) as TypePredicateNode;
node.parameterName = lhs;
node.type = parseType();
return finishNode(node);
}
function parseThisTypeNode(): ThisTypeNode {
const node = createNode(SyntaxKind.ThisType) as ThisTypeNode;
nextToken();
return finishNode(node);
}
@@ -2424,8 +2428,15 @@ namespace ts {
return parseStringLiteralTypeNode();
case SyntaxKind.VoidKeyword:
return parseTokenNode<TypeNode>();
case SyntaxKind.ThisKeyword:
return parseThisTypeNode();
case SyntaxKind.ThisKeyword: {
const thisKeyword = parseThisTypeNode();
if (token === SyntaxKind.IsKeyword && !scanner.hasPrecedingLineBreak()) {
return parseTypePredicate(thisKeyword);
}
else {
return thisKeyword;
}
}
case SyntaxKind.TypeOfKeyword:
return parseTypeQuery();
case SyntaxKind.OpenBraceToken:
src/compiler/types.ts
+29 -5
View File
@@ -733,11 +733,15 @@ namespace ts {
// @kind(SyntaxKind.StringKeyword)
// @kind(SyntaxKind.SymbolKeyword)
// @kind(SyntaxKind.VoidKeyword)
// @kind(SyntaxKind.ThisType)
export interface TypeNode extends Node {
_typeNodeBrand: any;
}
// @kind(SyntaxKind.ThisType)
export interface ThisTypeNode extends TypeNode {
_thisTypeNodeBrand: any;
}
export interface FunctionOrConstructorTypeNode extends TypeNode, SignatureDeclaration {
_functionOrConstructorTypeNodeBrand: any;
}
@@ -756,7 +760,7 @@ namespace ts {
// @kind(SyntaxKind.TypePredicate)
export interface TypePredicateNode extends TypeNode {
parameterName: Identifier;
parameterName: Identifier | ThisTypeNode;
type: TypeNode;
}
@@ -1820,10 +1824,25 @@ namespace ts {
CannotBeNamed
}
export const enum TypePredicateKind {
This,
Identifier
}
export interface TypePredicate {
kind: TypePredicateKind;
type: Type;
}
// @kind (TypePredicateKind.This)
export interface ThisTypePredicate extends TypePredicate {
_thisTypePredicateBrand: any;
}
// @kind (TypePredicateKind.Identifier)
export interface IdentifierTypePredicate extends TypePredicate {
parameterName: string;
parameterIndex: number;
type: Type;
}
/* @internal */
@@ -2091,6 +2110,7 @@ namespace ts {
ESSymbol = 0x01000000, // Type of symbol primitive introduced in ES6
ThisType = 0x02000000, // This type
ObjectLiteralPatternWithComputedProperties = 0x04000000, // Object literal type implied by binding pattern has computed properties
PredicateType = 0x08000000, // Predicate types are also Boolean types, but should not be considered Intrinsics - there's no way to capture this with flags
/* @internal */
Intrinsic = Any | String | Number | Boolean | ESSymbol | Void | Undefined | Null,
@@ -2102,7 +2122,7 @@ namespace ts {
UnionOrIntersection = Union | Intersection,
StructuredType = ObjectType | Union | Intersection,
/* @internal */
RequiresWidening = ContainsUndefinedOrNull | ContainsObjectLiteral,
RequiresWidening = ContainsUndefinedOrNull | ContainsObjectLiteral | PredicateType,
/* @internal */
PropagatingFlags = ContainsUndefinedOrNull | ContainsObjectLiteral | ContainsAnyFunctionType
}
@@ -2123,6 +2143,11 @@ namespace ts {
intrinsicName: string; // Name of intrinsic type
}
// Predicate types (TypeFlags.Predicate)
export interface PredicateType extends Type {
predicate: ThisTypePredicate | IdentifierTypePredicate;
}
// String literal types (TypeFlags.StringLiteral)
export interface StringLiteralType extends Type {
text: string; // Text of string literal
@@ -2239,7 +2264,6 @@ namespace ts {
declaration: SignatureDeclaration; // Originating declaration
typeParameters: TypeParameter[]; // Type parameters (undefined if non-generic)
parameters: Symbol[]; // Parameters
typePredicate?: TypePredicate; // Type predicate
/* @internal */
resolvedReturnType: Type; // Resolved return type
/* @internal */
src/compiler/utilities.ts
+4
View File
@@ -693,6 +693,10 @@ namespace ts {
return node && node.kind === SyntaxKind.MethodDeclaration && node.parent.kind === SyntaxKind.ObjectLiteralExpression;
}
export function isIdentifierTypePredicate(predicate: TypePredicate): predicate is IdentifierTypePredicate {
return predicate && predicate.kind === TypePredicateKind.Identifier;
}
export function getContainingFunction(node: Node): FunctionLikeDeclaration {
while (true) {
node = node.parent;