41 lines
1,021 B
Plaintext
41 lines
1,021 B
Plaintext
=== tests/cases/conformance/types/typeRelationships/subtypesAndSuperTypes/subtypingWithOptionalProperties.ts ===
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// subtyping is not transitive due to optional properties but the subtyping algorithm assumes it is for the 99% case
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// returns { s?: number; }
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function f<T>(a: T) {
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>f : <T>(a: T) => { s?: number; }
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>T : T
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>a : T
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>T : T
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var b: { s?: number } = a;
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>b : { s?: number; }
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>s : number
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>a : T
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return b;
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>b : { s?: number; }
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}
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var r = f({ s: new Object() }); // ok
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>r : { s?: number; }
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>f({ s: new Object() }) : { s?: number; }
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>f : <T>(a: T) => { s?: number; }
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>{ s: new Object() } : { s: Object; }
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>s : Object
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>new Object() : Object
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>Object : ObjectConstructor
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r.s && r.s.toFixed(); // would blow up at runtime
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>r.s && r.s.toFixed() : string
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>r.s : number
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>r : { s?: number; }
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>s : number
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>r.s.toFixed() : string
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>r.s.toFixed : (fractionDigits?: number) => string
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>r.s : number
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>r : { s?: number; }
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>s : number
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>toFixed : (fractionDigits?: number) => string
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