From ea68ce7fac0a5888e54e5725066b04fcd4290efa Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Tue, 28 Jun 2022 08:00:25 +0000 Subject: [PATCH] Revert a hack that only ever worked on level deep --- compiler/rustc_mir_build/src/thir/pattern/usefulness.rs | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs index 3203f801fa03..9e7a267ecbd7 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs @@ -967,11 +967,7 @@ pub(crate) fn compute_match_usefulness<'p, 'tcx>( }) .collect(); - // In case we're matching on an opaque type in its defining scope, the patterns define the hidden type. - // The wildcard pattern needs to have the same type, otherwise it will always be deemed useful, even if the - // match is exhaustive for the pattern type. - let wild_ty = arms.first().map_or(scrut_ty, |arm| arm.pat.ty()); - let wild_pattern = cx.pattern_arena.alloc(DeconstructedPat::wildcard(wild_ty)); + let wild_pattern = cx.pattern_arena.alloc(DeconstructedPat::wildcard(scrut_ty)); let v = PatStack::from_pattern(wild_pattern); let usefulness = is_useful(cx, &matrix, &v, FakeExtraWildcard, scrut_hir_id, false, true); let non_exhaustiveness_witnesses = match usefulness {