diff options
Diffstat (limited to 'src/test/ui/regions/type-param-outlives-reempty-issue-74429.rs')
-rw-r--r-- | src/test/ui/regions/type-param-outlives-reempty-issue-74429.rs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/src/test/ui/regions/type-param-outlives-reempty-issue-74429.rs b/src/test/ui/regions/type-param-outlives-reempty-issue-74429.rs new file mode 100644 index 000000000..d463f311c --- /dev/null +++ b/src/test/ui/regions/type-param-outlives-reempty-issue-74429.rs @@ -0,0 +1,35 @@ +// Regression test for #74429, where we didn't think that a type parameter +// outlived `ReEmpty`. + +// check-pass + +use std::marker::PhantomData; + +fn apply<T, F: FnOnce(T)>(_: T, _: F) {} + +#[derive(Clone, Copy)] +struct Invariant<T> { + t: T, + p: PhantomData<fn(T) -> T>, +} + +fn verify_reempty<T>(x: T) { + // r is inferred to have type `Invariant<&ReEmpty(U0) T>` + let r = Invariant { t: &x, p: PhantomData }; + // Creates a new universe, all variables from now on are in `U1`, say. + let _: fn(&()) = |_| {}; + // Closure parameter is of type `&ReEmpty(U1) T`, so the closure has an implied + // bound of `T: ReEmpty(U1)` + apply(&x, |_| { + // Requires `typeof(r)` is well-formed, i.e. `T: ReEmpty(U0)`. If we + // only have the implied bound from the closure parameter to use this + // requires `ReEmpty(U1): ReEmpty(U0)`, which isn't true so we reported + // an error. + // + // This doesn't happen any more because we ensure that `T: ReEmpty(U0)` + // is an implicit bound for all type parameters. + drop(r); + }); +} + +fn main() {} |