diff --git a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs index 339baf611f3c3..32bbd626d4e49 100644 --- a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs +++ b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs @@ -57,16 +57,12 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> { let ty = OpportunisticRegionResolver::new(self).fold_ty(ty); // We do not expect existential variables in implied bounds. - // We may however encounter unconstrained lifetime variables in invalid - // code. See #110161 for context. + // We may however encounter unconstrained lifetime variables + // in very rare cases. + // + // See `ui/implied-bounds/implied-bounds-unconstrained-2.rs` for + // an example. assert!(!ty.has_non_region_infer()); - if ty.has_infer() { - self.tcx.sess.delay_span_bug( - self.tcx.def_span(body_id), - "skipped implied_outlives_bounds due to unconstrained lifetimes", - ); - return vec![]; - } let mut canonical_var_values = OriginalQueryValues::default(); let canonical_ty = diff --git a/tests/ui/implied-bounds/implied-bounds-unconstrained-1.rs b/tests/ui/implied-bounds/implied-bounds-unconstrained-1.rs new file mode 100644 index 0000000000000..025e5176ff7ee --- /dev/null +++ b/tests/ui/implied-bounds/implied-bounds-unconstrained-1.rs @@ -0,0 +1,28 @@ +// check-pass + +// Regression test for #112832. +pub trait QueryDb { + type Db; +} + +pub struct QueryTable { + db: DB, + storage: Q, +} + +// We normalize `::Db` to `>::SendDb` +// using the where-bound. 'd is an unconstrained region variable which previously +// triggered an assert. +impl QueryTable::Db> where Q: for<'d> AsyncQueryFunction<'d> {} + +pub trait AsyncQueryFunction<'d>: QueryDb>::SendDb> { + type SendDb: 'd; +} + +pub trait QueryStorageOpsAsync +where + Q: for<'d> AsyncQueryFunction<'d>, +{ +} + +fn main() {} diff --git a/tests/ui/implied-bounds/implied-bounds-unconstrained-2.rs b/tests/ui/implied-bounds/implied-bounds-unconstrained-2.rs new file mode 100644 index 0000000000000..976054facee5e --- /dev/null +++ b/tests/ui/implied-bounds/implied-bounds-unconstrained-2.rs @@ -0,0 +1,20 @@ +// check-pass + +// Another minimized regression test for #112832. +trait Trait { + type Assoc; +} + +trait Sub<'a>: Trait>::SubAssoc> { + type SubAssoc; +} + +// By using the where-clause we normalize `::Assoc` to +// `>::SubAssoc` where `'a` is an unconstrained region +// variable. +fn foo(x: ::Assoc) +where + for<'a> T: Sub<'a>, +{} + +fn main() {}