tests/cases/conformance/expressions/contextualTyping/functionExpressionContextualTyping2.ts(11,1): error TS2322: Type '(foo: number, bar: string) => boolean' is not assignable to type '((n: number, s: string) => number) | ((n: number, s: string) => string)'.
  Type '(foo: number, bar: string) => boolean' is not assignable to type '(n: number, s: string) => string'.
    Type 'boolean' is not assignable to type 'string'.


==== tests/cases/conformance/expressions/contextualTyping/functionExpressionContextualTyping2.ts (1 errors) ====
    // A contextual signature S is extracted from a function type T as follows:
    //      If T is a function type with exactly one call signature, and if that call signature is non- generic, S is that signature.
    //      If T is a union type, let U be the set of element types in T that have call signatures.
    //          If each type in U has exactly one call signature and that call signature is non- generic,
    //          and if all of the signatures are identical ignoring return types, then S is a signature
    //          with the same parameters and a union of the return types.
    //      Otherwise, no contextual signature can be extracted from T and S is undefined.
    
    var a0: (n: number, s: string) => number
    var a1: typeof a0 | ((n: number, s: string) => string);
    a1 = (foo, bar) => { return true; }  // Error
    ~~
!!! error TS2322: Type '(foo: number, bar: string) => boolean' is not assignable to type '((n: number, s: string) => number) | ((n: number, s: string) => string)'.
!!! error TS2322:   Type '(foo: number, bar: string) => boolean' is not assignable to type '(n: number, s: string) => string'.
!!! error TS2322:     Type 'boolean' is not assignable to type 'string'.