tests/cases/compiler/contextualTypingWithFixedTypeParameters1.ts(2,22): error TS2339: Property 'foo' does not exist on type 'string'. tests/cases/compiler/contextualTypingWithFixedTypeParameters1.ts(3,32): error TS2339: Property 'foo' does not exist on type 'string'. tests/cases/compiler/contextualTypingWithFixedTypeParameters1.ts(3,38): error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'. ==== tests/cases/compiler/contextualTypingWithFixedTypeParameters1.ts (3 errors) ==== var f10: (x: T, b: () => (a: T) => void, y: T) => T; f10('', () => a => a.foo, ''); // a is string ~~~ !!! error TS2339: Property 'foo' does not exist on type 'string'. var r9 = f10('', () => (a => a.foo), 1); // error ~~~ !!! error TS2339: Property 'foo' does not exist on type 'string'. ~ !!! error TS2345: Argument of type 'number' is not assignable to parameter of type 'string'.