51 lines
2.5 KiB
TypeScript
51 lines
2.5 KiB
TypeScript
//// [contextualSignatureInstantiation.ts]
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// TypeScript Spec, section 4.12.2:
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// If e is an expression of a function type that contains exactly one generic call signature and no other members,
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// and T is a function type with exactly one non - generic call signature and no other members, then any inferences
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// made for type parameters referenced by the parameters of T's call signature are fixed, and e's type is changed
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// to a function type with e's call signature instantiated in the context of T's call signature (section 3.8.5).
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declare function foo<T>(cb: (x: number, y: string) => T): T;
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declare function bar<T, U, V>(x: T, y: U, cb: (x: T, y: U) => V): V;
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declare function baz<T, U>(x: T, y: T, cb: (x: T, y: T) => U): U;
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declare function g<T>(x: T, y: T): T;
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declare function h<T, U>(x: T, y: U): T[] | U[];
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var a: number;
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var a = bar(1, 1, g); // Should be number
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var a = baz(1, 1, g); // Should be number
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var b: number | string;
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var b = foo(g); // Should be number | string
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var b = bar(1, "one", g); // Should be number | string
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var b = bar("one", 1, g); // Should be number | string
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var b = baz(b, b, g); // Should be number | string
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var d: number[] | string[];
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var d = foo(h); // Should be number[] | string[]
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var d = bar(1, "one", h); // Should be number[] | string[]
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var d = bar("one", 1, h); // Should be number[] | string[]
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var d = baz(d, d, g); // Should be number[] | string[]
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//// [contextualSignatureInstantiation.js]
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// TypeScript Spec, section 4.12.2:
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// If e is an expression of a function type that contains exactly one generic call signature and no other members,
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// and T is a function type with exactly one non - generic call signature and no other members, then any inferences
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// made for type parameters referenced by the parameters of T's call signature are fixed, and e's type is changed
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// to a function type with e's call signature instantiated in the context of T's call signature (section 3.8.5).
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var a;
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var a = bar(1, 1, g); // Should be number
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var a = baz(1, 1, g); // Should be number
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var b;
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var b = foo(g); // Should be number | string
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var b = bar(1, "one", g); // Should be number | string
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var b = bar("one", 1, g); // Should be number | string
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var b = baz(b, b, g); // Should be number | string
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var d;
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var d = foo(h); // Should be number[] | string[]
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var d = bar(1, "one", h); // Should be number[] | string[]
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var d = bar("one", 1, h); // Should be number[] | string[]
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var d = baz(d, d, g); // Should be number[] | string[]
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