35 lines
900 B
Rust
35 lines
900 B
Rust
// Test that the NLL solver cannot find a solution
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// for `exists<R1> { forall<R1> { R2: R1 } }`.
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//
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// In this test, the impl should match `fn(T)` for some `T`,
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// but we ask it to match `for<'a> fn(&'a ())`. Due to argument
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// contravariance, this effectively requires a `T = &'b ()` where
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// `forall<'a> { 'a: 'b }`. Therefore, we get an error.
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//
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// Note the use of `-Zno-leak-check` here. This is presently required in order
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// to skip the leak-check errors.
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//
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// c.f. Issue #57642.
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//
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// compile-flags:-Zno-leak-check
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trait Y {
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type F;
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fn make_f() -> Self::F;
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}
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impl<T> Y for fn(T) {
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type F = fn(T);
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fn make_f() -> Self::F {
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|_| {}
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}
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}
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fn main() {
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let _x = <fn(&())>::make_f();
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//~^ ERROR implementation of `Y` is not general enough
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//~| ERROR implementation of `Y` is not general enough
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//~| ERROR implementation of `Y` is not general enough
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}
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