31 lines
1.1 KiB
Plaintext
31 lines
1.1 KiB
Plaintext
==== tests/cases/conformance/types/typeParameters/typeArgumentLists/typeParameterAsTypeParameterConstraint.ts (2 errors) ====
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// using a type parameter as a constraint for a type parameter is valid
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// no errors expected except illegal constraints
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function foo<T, U extends T>(x: T, y: U): U { return y; }
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~~~~~~~~~~~
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!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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var r = foo(1, 2);
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var r = foo({}, 1);
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interface A {
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foo: string;
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}
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interface B extends A {
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bar: number;
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}
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var a: A;
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var b: B;
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var r2 = foo(a, b);
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var r3 = foo({ x: 1 }, { x: 2, y: 3 });
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function foo2<T, U extends { length: T }>(x: T, y: U) { return y; }
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~~~~~~~~~~~~~~~~~~~~~~~
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!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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foo2(1, '');
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foo2({}, { length: 2 });
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foo2(1, { width: 3, length: 2 });
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foo2(1, []);
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foo2(1, ['']); |