32 lines
705 B
JavaScript
32 lines
705 B
JavaScript
class Variance<+Out,-In> {
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foo(x: Out): Out { return x; }
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bar(y: In): In { return y; }
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}
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class A { }
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class B extends A { }
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function subtyping(
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v1: Variance<A,B>,
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v2: Variance<B,A>
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) {
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(v1: Variance<B,A>); // error on both targs (A ~/~> B)
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(v2: Variance<A,B>); // OK for both targs (B ~> A)
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}
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class PropVariance<+Out,-In> {
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inv1: Out; // error
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inv2: In; // error
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-co1: Out; // error
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-co2: In; // ok
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+con1: Out; // ok
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+con2: In; // error
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inv_dict1: {[k:string]: Out}; // error
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inv_dict2: {[k:string]: In}; // error
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co_dict1: {+[k:string]: Out}; // ok
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co_dict2: {+[k:string]: In}; // error
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con_dict1: {-[k:string]: Out}; // error
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con_dict2: {-[k:string]: In}; // ok
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}
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