48 lines
No EOL
2.2 KiB
Text
48 lines
No EOL
2.2 KiB
Text
tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithObjectTypeArgsAndConstraints3.ts(18,10): error TS2453: The type argument for type parameter 'T' cannot be inferred from the usage. Consider specifying the type arguments explicitly:
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Type argument candidate 'Derived' is not a valid type argument because it is not a supertype of candidate 'Derived2'.
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tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithObjectTypeArgsAndConstraints3.ts(20,29): error TS2313: Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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==== tests/cases/conformance/types/typeRelationships/typeInference/genericCallWithObjectTypeArgsAndConstraints3.ts (2 errors) ====
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// Generic call with constraints infering type parameter from object member properties
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class Base {
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x: string;
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}
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class Derived extends Base {
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y: string;
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}
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class Derived2 extends Base {
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z: string;
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}
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function f<T extends Base>(a: { x: T; y: T }) {
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var r: T;
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return r;
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}
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var r1 = f({ x: new Derived(), y: new Derived2() }); // error because neither is supertype of the other
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~
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!!! error TS2453: The type argument for type parameter 'T' cannot be inferred from the usage. Consider specifying the type arguments explicitly:
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!!! error TS2453: Type argument candidate 'Derived' is not a valid type argument because it is not a supertype of candidate 'Derived2'.
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function f2<T extends Base, U extends { x: T; y: T }>(a: U) {
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~~~~~~~~~~~~~~~~~~~~~~~~
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!!! error TS2313: Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
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var r: T;
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return r;
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}
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var r2 = f2({ x: new Derived(), y: new Derived2() }); // ok
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var r3 = f2({ x: new Derived(), y: new Derived2() }); // ok
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function f3<T extends Base>(y: (a: T) => T, x: T) {
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return y(null);
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}
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// all ok - second argument is processed before x is fixed
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var r4 = f3(x => x, new Base());
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var r5 = f3(x => x, new Derived());
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var r6 = f3(x => x, null);
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