diff options
7 files changed, 106 insertions, 4 deletions
diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs index 8cca4c6231f..1f071a9ff0b 100644 --- a/compiler/rustc_infer/src/infer/canonical/query_response.rs +++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs @@ -483,7 +483,13 @@ impl<'tcx> InferCtxt<'tcx> { let result_subst = CanonicalVarValues { var_values: self.tcx.mk_args_from_iter( query_response.variables.iter().enumerate().map(|(index, info)| { - if info.is_existential() { + if info.universe() != ty::UniverseIndex::ROOT { + // A variable from inside a binder of the query. While ideally these shouldn't + // exist at all, we have to deal with them for now. + self.instantiate_canonical_var(cause.span, info, |u| { + universe_map[u.as_usize()] + }) + } else if info.is_existential() { match opt_values[BoundVar::new(index)] { Some(k) => k, None => self.instantiate_canonical_var(cause.span, info, |u| { @@ -491,9 +497,11 @@ impl<'tcx> InferCtxt<'tcx> { }), } } else { - self.instantiate_canonical_var(cause.span, info, |u| { - universe_map[u.as_usize()] - }) + // For placeholders which were already part of the input, we simply map this + // universal bound variable back the placeholder of the input. + opt_values[BoundVar::new(index)].expect( + "expected placeholder to be unified with itself during response", + ) } }), ), diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.current.stderr b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.current.stderr new file mode 100644 index 00000000000..4082d6d47e7 --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.current.stderr @@ -0,0 +1,11 @@ +warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/unifying-placeholders-in-query-response-2.rs:5:12 + | +LL | #![feature(non_lifetime_binders)] + | ^^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted + diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.next.stderr b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.next.stderr new file mode 100644 index 00000000000..4082d6d47e7 --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.next.stderr @@ -0,0 +1,11 @@ +warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/unifying-placeholders-in-query-response-2.rs:5:12 + | +LL | #![feature(non_lifetime_binders)] + | ^^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted + diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.rs b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.rs new file mode 100644 index 00000000000..bbf1a1f72db --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response-2.rs @@ -0,0 +1,23 @@ +// revisions: current next +//[next] compile-flags: -Znext-solver +// check-pass + +#![feature(non_lifetime_binders)] +//~^ WARN the feature `non_lifetime_binders` is incomplete + +trait Id { + type Output: ?Sized; +} + +impl<T: ?Sized> Id for T { + type Output = T; +} + +trait Everyone {} +impl<T: ?Sized> Everyone for T {} + +fn hello() where for<T> <T as Id>::Output: Everyone {} + +fn main() { + hello(); +} diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.current.stderr b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.current.stderr new file mode 100644 index 00000000000..040009efbde --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.current.stderr @@ -0,0 +1,11 @@ +warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/unifying-placeholders-in-query-response.rs:5:12 + | +LL | #![feature(non_lifetime_binders)] + | ^^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted + diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.next.stderr b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.next.stderr new file mode 100644 index 00000000000..040009efbde --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.next.stderr @@ -0,0 +1,11 @@ +warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes + --> $DIR/unifying-placeholders-in-query-response.rs:5:12 + | +LL | #![feature(non_lifetime_binders)] + | ^^^^^^^^^^^^^^^^^^^^ + | + = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information + = note: `#[warn(incomplete_features)]` on by default + +warning: 1 warning emitted + diff --git a/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.rs b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.rs new file mode 100644 index 00000000000..5e28a2ba8b9 --- /dev/null +++ b/tests/ui/traits/non_lifetime_binders/unifying-placeholders-in-query-response.rs @@ -0,0 +1,27 @@ +// revisions: current next +//[next] compile-flags: -Znext-solver +// check-pass + +#![feature(non_lifetime_binders)] +//~^ WARN the feature `non_lifetime_binders` is incomplete + +pub trait Foo<T: ?Sized> { + type Bar<K: ?Sized>: ?Sized; +} + +impl Foo<usize> for () { + type Bar<K: ?Sized> = K; +} + +pub fn f<T1, T2>(a: T1, b: T2) +where + T1: for<T> Foo<usize, Bar<T> = T>, + T2: for<T> Foo<usize, Bar<T> = <T1 as Foo<usize>>::Bar<T>>, +{ +} + +fn it_works() { + f((), ()); +} + +fn main() {} |