diff options
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/select/mod.rs | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 5e32a27cdb1..0ed59223337 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -1737,12 +1737,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { (&ImplCandidate(other_def), &ImplCandidate(victim_def)) => { // See if we can toss out `victim` based on specialization. - // This requires us to know *for sure* that the `other` impl applies - // i.e., `EvaluatedToOk`. + // While this requires us to know *for sure* that the `other` impl applies + // we still use modulo regions here. // - // FIXME(@lcnr): Using `modulo_regions` here seems kind of scary - // to me but is required for `std` to compile, so I didn't change it - // for now. + // This is fine as specialization currently assumes that specializing + // impls have to be always applicable, meaning that the only allowed + // region constraints may be constraints also present on the default impl. let tcx = self.tcx(); if other.evaluation.must_apply_modulo_regions() { if tcx.specializes((other_def, victim_def)) { |