1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
|
//// [functionExpressionContextualTyping2.ts]
// 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
//// [functionExpressionContextualTyping2.js]
// 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;
var a1;
a1 = function (foo, bar) { return true; }; // Error
|
