Merge branch 'master' into fix19349

src/compiler/checker.ts

@@ -6726,6 +6726,16 @@ namespace ts {
                 isInJavaScriptFile(signature.declaration));
         }
 
+        function getBaseSignature(signature: Signature) {
+            const typeParameters = signature.typeParameters;
+            if (typeParameters) {
+                const typeEraser = createTypeEraser(typeParameters);
+                const baseConstraints = map(typeParameters, tp => instantiateType(getBaseConstraintOfType(tp), typeEraser) || emptyObjectType);
+                return instantiateSignature(signature, createTypeMapper(typeParameters, baseConstraints), /*eraseTypeParameters*/ true);
+            }
+            return signature;
+        }
+
         function getOrCreateTypeFromSignature(signature: Signature): ObjectType {
             // There are two ways to declare a construct signature, one is by declaring a class constructor
             // using the constructor keyword, and the other is declaring a bare construct signature in an
@@ -10955,7 +10965,7 @@ namespace ts {
                 const targetLen = targetSignatures.length;
                 const len = sourceLen < targetLen ? sourceLen : targetLen;
                 for (let i = 0; i < len; i++) {
-                    inferFromSignature(getErasedSignature(sourceSignatures[sourceLen - len + i]), getErasedSignature(targetSignatures[targetLen - len + i]));
+                    inferFromSignature(getBaseSignature(sourceSignatures[sourceLen - len + i]), getBaseSignature(targetSignatures[targetLen - len + i]));
                 }
             }
 
@@ -13430,7 +13440,7 @@ namespace ts {
         // exists. Otherwise, it is the type of the string index signature in T, if one exists.
         function getContextualTypeForObjectLiteralMethod(node: MethodDeclaration): Type {
             Debug.assert(isObjectLiteralMethod(node));
-            if (isInsideWithStatementBody(node)) {
+            if (node.flags & NodeFlags.InWithStatement) {
                 // We cannot answer semantic questions within a with block, do not proceed any further
                 return undefined;
             }
@@ -13549,7 +13559,7 @@ namespace ts {
          * @returns the contextual type of an expression.
          */
         function getContextualType(node: Expression): Type | undefined {
-            if (isInsideWithStatementBody(node)) {
+            if (node.flags & NodeFlags.InWithStatement) {
                 // We cannot answer semantic questions within a with block, do not proceed any further
                 return undefined;
             }
@@ -23114,21 +23124,8 @@ namespace ts {
 
         // Language service support
 
-        function isInsideWithStatementBody(node: Node): boolean {
-            if (node) {
-                while (node.parent) {
-                    if (node.parent.kind === SyntaxKind.WithStatement && (<WithStatement>node.parent).statement === node) {
-                        return true;
-                    }
-                    node = node.parent;
-                }
-            }
-
-            return false;
-        }
-
         function getSymbolsInScope(location: Node, meaning: SymbolFlags): Symbol[] {
-            if (isInsideWithStatementBody(location)) {
+            if (location.flags & NodeFlags.InWithStatement) {
                 // We cannot answer semantic questions within a with block, do not proceed any further
                 return [];
             }
@@ -23428,7 +23425,7 @@ namespace ts {
                 return isExternalModule(<SourceFile>node) ? getMergedSymbol(node.symbol) : undefined;
             }
 
-            if (isInsideWithStatementBody(node)) {
+            if (node.flags & NodeFlags.InWithStatement) {
                 // We cannot answer semantic questions within a with block, do not proceed any further
                 return undefined;
             }
@@ -23536,7 +23533,7 @@ namespace ts {
         }
 
         function getTypeOfNode(node: Node): Type {
-            if (isInsideWithStatementBody(node)) {
+            if (node.flags & NodeFlags.InWithStatement) {
                 // We cannot answer semantic questions within a with block, do not proceed any further
                 return unknownType;
             }

src/compiler/parser.ts

@@ -4724,7 +4724,7 @@ namespace ts {
             parseExpected(SyntaxKind.OpenParenToken);
             node.expression = allowInAnd(parseExpression);
             parseExpected(SyntaxKind.CloseParenToken);
-            node.statement = parseStatement();
+            node.statement = doInsideOfContext(NodeFlags.InWithStatement, parseStatement);
             return finishNode(node);
         }
 

src/compiler/types.ts

@@ -451,6 +451,7 @@ namespace ts {
         /* @internal */
         PossiblyContainsDynamicImport = 1 << 19,
         JSDoc =              1 << 20, // If node was parsed inside jsdoc
+        /* @internal */ InWithStatement =    1 << 21, // If any ancestor of node was the `statement` of a WithStatement (not the `expression`)
 
         BlockScoped = Let | Const,
 
@@ -458,7 +459,7 @@ namespace ts {
         ReachabilityAndEmitFlags = ReachabilityCheckFlags | HasAsyncFunctions,
 
         // Parsing context flags
-        ContextFlags = DisallowInContext | YieldContext | DecoratorContext | AwaitContext | JavaScriptFile,
+        ContextFlags = DisallowInContext | YieldContext | DecoratorContext | AwaitContext | JavaScriptFile | InWithStatement,
 
         // Exclude these flags when parsing a Type
         TypeExcludesFlags = YieldContext | AwaitContext,

src/services/codefixes/fixCannotFindModule.ts

@@ -2,7 +2,6 @@
 namespace ts.codefix {
     registerCodeFix({
         errorCodes: [
-            Diagnostics.Cannot_find_module_0.code,
             Diagnostics.Could_not_find_a_declaration_file_for_module_0_1_implicitly_has_an_any_type.code,
         ],
         getCodeActions: context => {