safe transmute: gracefully handle const params of wrong types

ref: https://github.com/rust-lang/rust/pull/92268/files#r925244819
2022-07-20 19:57:55 +00:00 · 2022-07-20 19:57:55 +00:00 · 18751a708a
commit 18751a708a
parent bc4a1dea41
3 changed files with 68 additions and 1 deletions
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@ -288,7 +288,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                .substs
                .const_at(i)
                .try_eval_bool(self.tcx(), obligation.param_env)
-                .unwrap()
+                .unwrap_or(true)
        };

        let src_and_dst = predicate.map_bound(|p| rustc_transmute::Types {