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=== tests/cases/conformance/expressions/contextualTyping/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
>a0 : (n: number, s: string) => number
>n : number
>s : string
var a1: typeof a0 | ((n: number, s: string) => string);
>a1 : ((n: number, s: string) => number) | ((n: number, s: string) => string)
>a0 : (n: number, s: string) => number
>n : number
>s : string
a1 = (foo, bar) => { return true; } // Error
>a1 = (foo, bar) => { return true; } : (foo: number, bar: string) => boolean
>a1 : ((n: number, s: string) => number) | ((n: number, s: string) => string)
>(foo, bar) => { return true; } : (foo: number, bar: string) => boolean
>foo : number
>bar : string
>true : true
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