31 lines
689 B
Rust
31 lines
689 B
Rust
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// Illustrates the "projection gap": in this test, even though we know
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// that `T::Foo: 'x`, that does not tell us that `T: 'x`, because
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// there might be other ways for the caller of `func` to show that
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// `T::Foo: 'x` holds (e.g., where-clause).
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trait Trait1<'x> {
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type Foo;
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}
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// calling this fn should trigger a check that the type argument
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// supplied is well-formed.
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fn wf<T>() { }
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fn func<'x, T:Trait1<'x>>(t: &'x T::Foo)
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{
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wf::<&'x T>();
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//~^ ERROR the parameter type `T` may not live long enough
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}
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fn caller2<'x, T:Trait1<'x>>(t: &'x T)
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{
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wf::<&'x T::Foo>(); // OK
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}
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fn caller3<'x, T:Trait1<'x>>(t: &'x T::Foo)
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{
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wf::<&'x T::Foo>(); // OK
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}
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fn main() { }
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