exclude iffes from getContextualType

Author: Andarist

src/compiler/checker.ts

@@ -32149,6 +32149,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             case SyntaxKind.CallExpression:
             case SyntaxKind.NewExpression:
                 if (node === (parent as CallExpression | NewExpression).expression) {
+                    if (getImmediatelyInvokedFunctionExpression(skipParentheses(node))) {
+                        // iifes themselves can't be contextually-typed (unlike their parameters)
+                        return undefined;
+                    }
                     return getContextualType(parent as CallExpression | NewExpression, contextFlags);
                 }
                 return getContextualTypeForArgument(parent as CallExpression | NewExpression, node);

tests/baselines/reference/generatorTypeCheck64.symbols

@@ -0,0 +1,35 @@
+//// [tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck64.ts] ////
+
+=== generatorTypeCheck64.ts ===
+function* g3(): Generator<Generator<(x: string) => number>> {
+>g3 : Symbol(g3, Decl(generatorTypeCheck64.ts, 0, 0))
+>Generator : Symbol(Generator, Decl(lib.es2015.generator.d.ts, --, --))
+>Generator : Symbol(Generator, Decl(lib.es2015.generator.d.ts, --, --))
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 0, 37))
+
+    yield function* () {
+        yield x => x.length;
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 2, 13))
+>x.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 2, 13))
+>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+
+    } ()
+}
+
+function* g4(): Iterator<Iterable<(x: string) => number>> {
+>g4 : Symbol(g4, Decl(generatorTypeCheck64.ts, 4, 1))
+>Iterator : Symbol(Iterator, Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.esnext.iterator.d.ts, --, --))
+>Iterable : Symbol(Iterable, Decl(lib.es2015.iterable.d.ts, --, --))
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 6, 35))
+
+  yield (function* () {
+    yield (x) => x.length;
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 8, 11))
+>x.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+>x : Symbol(x, Decl(generatorTypeCheck64.ts, 8, 11))
+>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
+
+  })();
+}
+

tests/baselines/reference/generatorTypeCheck64.types

@@ -0,0 +1,67 @@
+//// [tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck64.ts] ////
+
+=== Performance Stats ===
+Type Count: 1,000
+Instantiation count: 2,500
+
+=== generatorTypeCheck64.ts ===
+function* g3(): Generator<Generator<(x: string) => number>> {
+>g3 : () => Generator<Generator<(x: string) => number>>
+>   : ^^^^^^                                           
+>x : string
+>  : ^^^^^^
+
+    yield function* () {
+>yield function* () {        yield x => x.length;    } () : any
+>function* () {        yield x => x.length;    } () : Generator<(x: string) => number, void, any>
+>                                                   : ^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>function* () {        yield x => x.length;    } : () => Generator<(x: string) => number, void, any>
+>                                                : ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+        yield x => x.length;
+>yield x => x.length : any
+>x => x.length : (x: string) => number
+>              : ^ ^^^^^^^^^^^^^^^^^^^
+>x : string
+>  : ^^^^^^
+>x.length : number
+>         : ^^^^^^
+>x : string
+>  : ^^^^^^
+>length : number
+>       : ^^^^^^
+
+    } ()
+}
+
+function* g4(): Iterator<Iterable<(x: string) => number>> {
+>g4 : () => Iterator<Iterable<(x: string) => number>>
+>   : ^^^^^^                                         
+>x : string
+>  : ^^^^^^
+
+  yield (function* () {
+>yield (function* () {    yield (x) => x.length;  })() : any
+>(function* () {    yield (x) => x.length;  })() : Generator<(x: string) => number, void, any>
+>                                                : ^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>(function* () {    yield (x) => x.length;  }) : () => Generator<(x: string) => number, void, any>
+>                                              : ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>function* () {    yield (x) => x.length;  } : () => Generator<(x: string) => number, void, any>
+>                                            : ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+    yield (x) => x.length;
+>yield (x) => x.length : any
+>(x) => x.length : (x: string) => number
+>                : ^ ^^^^^^^^^^^^^^^^^^^
+>x : string
+>  : ^^^^^^
+>x.length : number
+>         : ^^^^^^
+>x : string
+>  : ^^^^^^
+>length : number
+>       : ^^^^^^
+
+  })();
+}
+

tests/cases/conformance/es6/yieldExpressions/generatorTypeCheck64.ts

@@ -0,0 +1,15 @@
+// @strict: true
+// @target: esnext
+// @noEmit: true
+
+function* g3(): Generator<Generator<(x: string) => number>> {
+    yield function* () {
+        yield x => x.length;
+    } ()
+}
+
+function* g4(): Iterator<Iterable<(x: string) => number>> {
+  yield (function* () {
+    yield (x) => x.length;
+  })();
+}