f9dcd9ef98
* Don't record Ternary.Maybe results in cache during recursive variance measurement * Add regression test * Accept new baselines * Use Ternary.Unknown to signal variance recursion * Add comments * Fix comment
78 lines
1.6 KiB
TypeScript
78 lines
1.6 KiB
TypeScript
// @strict: true
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// The type below should be invariant in T but is measured as covariant because
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// we don't analyze recursive references.
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interface Foo1<T> {
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x: T;
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y: Foo1<(arg: T) => void>;
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}
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declare const f10: Foo1<string>;
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const f11: Foo1<'a'> = f10;
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const f12: Foo1<unknown> = f10;
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// The type below is invariant in T and is measured as such.
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interface Foo2<T> {
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x: T;
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y: { x: (arg: T) => void, y: Foo2<(arg: T) => void>; }
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}
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declare const f20: Foo2<string>;
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const f21: Foo2<'a'> = f20;
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const f22: Foo2<unknown> = f20;
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// The type below should be invariant in T but is measured as covariant because
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// we don't analyze recursive references.
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type Foo3<T> = {
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x: T;
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y: Foo3<(arg: T) => void>;
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}
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declare const f30: Foo3<string>;
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const f31: Foo3<'a'> = f30;
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const f32: Foo3<unknown> = f30;
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// The type below is invariant in T and is measured as such.
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type Foo4<T> = {
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x: T;
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y: { x: (arg: T) => void, y: Foo4<(arg: T) => void>; }
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}
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declare const f40: Foo4<string>;
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const f41: Foo4<'a'> = f40;
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const f42: Foo4<unknown> = f40;
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// Repro from #3580
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interface Fn<A, B> {
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(a: A): B;
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then<C>(next: Fn<B, C>): Fn<A, C>;
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}
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declare const fn: Fn<string, number>;
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// Contravariant in A
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const fn1: Fn<unknown, number> = fn; // Error
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const fn2: Fn<'a', number> = fn;
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// Covariant in B
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const fn3: Fn<string, unknown> = fn;
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const fn4: Fn<string, 0> = fn; // Error
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// Repro from #39947
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interface I<Dummy, V> {
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c: C<Dummy, V>;
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}
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class C<Dummy, V> {
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declare sub: I<Dummy, V>;
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declare covariance: V;
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}
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const c1: C<unknown, string> = new C<unknown, number>(); // Error
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