From 2a87bae48d415b9ced69ae52513f004d06e34283 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Thu, 16 Nov 2023 04:28:22 +0100 Subject: Reveal opaque types in exhaustiveness checking --- compiler/rustc_pattern_analysis/src/usefulness.rs | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) (limited to 'compiler/rustc_pattern_analysis/src/usefulness.rs') diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs index 6b1de807797..6b9fbd73003 100644 --- a/compiler/rustc_pattern_analysis/src/usefulness.rs +++ b/compiler/rustc_pattern_analysis/src/usefulness.rs @@ -865,24 +865,14 @@ impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { matrix } - fn head_ty(&self) -> Option { + fn head_ty(&self, mcx: MatchCtxt<'a, 'p, Cx>) -> Option { if self.column_count() == 0 { return None; } - let mut ty = self.wildcard_row.head().ty(); - // If the type is opaque and it is revealed anywhere in the column, we take the revealed - // version. Otherwise we could encounter constructors for the revealed type and crash. - if Cx::is_opaque_ty(ty) { - for pat in self.heads() { - let pat_ty = pat.ty(); - if !Cx::is_opaque_ty(pat_ty) { - ty = pat_ty; - break; - } - } - } - Some(ty) + let ty = self.wildcard_row.head().ty(); + // FIXME(Nadrieril): `Cx` should only give us revealed types. + Some(mcx.tycx.reveal_opaque_ty(ty)) } fn column_count(&self) -> usize { self.wildcard_row.len() @@ -1181,7 +1171,7 @@ fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: TypeCx>( ) -> WitnessMatrix { debug_assert!(matrix.rows().all(|r| r.len() == matrix.column_count())); - let Some(ty) = matrix.head_ty() else { + let Some(ty) = matrix.head_ty(mcx) else { // The base case: there are no columns in the matrix. We are morally pattern-matching on (). // A row is useful iff it has no (unguarded) rows above it. for row in matrix.rows_mut() { -- cgit 1.4.1-3-g733a5