diff options
Diffstat (limited to 'compiler/rustc_mir_build/src/thir/pattern/usefulness.rs')
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/usefulness.rs | 36 |
1 files changed, 24 insertions, 12 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs index be66d0d47..d8f66a175 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs @@ -318,6 +318,8 @@ pub(crate) struct MatchCheckCtxt<'p, 'tcx> { pub(crate) module: DefId, pub(crate) param_env: ty::ParamEnv<'tcx>, pub(crate) pattern_arena: &'p TypedArena<DeconstructedPat<'p, 'tcx>>, + /// Only produce `NON_EXHAUSTIVE_OMITTED_PATTERNS` lint on refutable patterns. + pub(crate) refutable: bool, } impl<'a, 'tcx> MatchCheckCtxt<'a, 'tcx> { @@ -603,7 +605,7 @@ impl<'p, 'tcx> Usefulness<'p, 'tcx> { let new_patterns = if pcx.is_non_exhaustive { // Here we don't want the user to try to list all variants, we want them to add // a wildcard, so we only suggest that. - vec![DeconstructedPat::wildcard(pcx.ty)] + vec![DeconstructedPat::wildcard(pcx.ty, pcx.span)] } else { let mut split_wildcard = SplitWildcard::new(pcx); split_wildcard.split(pcx, matrix.heads().map(DeconstructedPat::ctor)); @@ -630,7 +632,7 @@ impl<'p, 'tcx> Usefulness<'p, 'tcx> { .collect(); if hide_variant_show_wild { - new.push(DeconstructedPat::wildcard(pcx.ty)); + new.push(DeconstructedPat::wildcard(pcx.ty, pcx.span)); } new @@ -733,7 +735,7 @@ impl<'p, 'tcx> Witness<'p, 'tcx> { let arity = ctor.arity(pcx); let pats = self.0.drain((len - arity)..).rev(); let fields = Fields::from_iter(pcx.cx, pats); - DeconstructedPat::new(ctor.clone(), fields, pcx.ty, DUMMY_SP) + DeconstructedPat::new(ctor.clone(), fields, pcx.ty, pcx.span) }; self.0.push(pat); @@ -764,13 +766,13 @@ impl<'p, 'tcx> Witness<'p, 'tcx> { /// `is_under_guard` is used to inform if the pattern has a guard. If it /// has one it must not be inserted into the matrix. This shouldn't be /// relied on for soundness. -#[instrument(level = "debug", skip(cx, matrix, hir_id), ret)] +#[instrument(level = "debug", skip(cx, matrix, lint_root), ret)] fn is_useful<'p, 'tcx>( cx: &MatchCheckCtxt<'p, 'tcx>, matrix: &Matrix<'p, 'tcx>, v: &PatStack<'p, 'tcx>, witness_preference: ArmType, - hir_id: HirId, + lint_root: HirId, is_under_guard: bool, is_top_level: bool, ) -> Usefulness<'p, 'tcx> { @@ -803,7 +805,7 @@ fn is_useful<'p, 'tcx>( for v in v.expand_or_pat() { debug!(?v); let usefulness = ensure_sufficient_stack(|| { - is_useful(cx, &matrix, &v, witness_preference, hir_id, is_under_guard, false) + is_useful(cx, &matrix, &v, witness_preference, lint_root, is_under_guard, false) }); debug!(?usefulness); ret.extend(usefulness); @@ -836,7 +838,7 @@ fn is_useful<'p, 'tcx>( pcx, matrix.heads(), matrix.column_count().unwrap_or(0), - hir_id, + lint_root, ) } // We split the head constructor of `v`. @@ -851,7 +853,15 @@ fn is_useful<'p, 'tcx>( let spec_matrix = start_matrix.specialize_constructor(pcx, &ctor); let v = v.pop_head_constructor(pcx, &ctor); let usefulness = ensure_sufficient_stack(|| { - is_useful(cx, &spec_matrix, &v, witness_preference, hir_id, is_under_guard, false) + is_useful( + cx, + &spec_matrix, + &v, + witness_preference, + lint_root, + is_under_guard, + false, + ) }); let usefulness = usefulness.apply_constructor(pcx, start_matrix, &ctor); @@ -859,6 +869,8 @@ fn is_useful<'p, 'tcx>( // that has the potential to trigger the `non_exhaustive_omitted_patterns` lint. // To understand the workings checkout `Constructor::split` and `SplitWildcard::new/into_ctors` if is_non_exhaustive_and_wild + // Only emit a lint on refutable patterns. + && cx.refutable // We check that the match has a wildcard pattern and that wildcard is useful, // meaning there are variants that are covered by the wildcard. Without the check // for `witness_preference` the lint would trigger on `if let NonExhaustiveEnum::A = foo {}` @@ -893,7 +905,7 @@ fn is_useful<'p, 'tcx>( // NB: The partner lint for structs lives in `compiler/rustc_hir_analysis/src/check/pat.rs`. cx.tcx.emit_spanned_lint( NON_EXHAUSTIVE_OMITTED_PATTERNS, - hir_id, + lint_root, pcx.span, NonExhaustiveOmittedPattern { scrut_ty: pcx.ty, @@ -951,7 +963,7 @@ pub(crate) struct UsefulnessReport<'p, 'tcx> { pub(crate) fn compute_match_usefulness<'p, 'tcx>( cx: &MatchCheckCtxt<'p, 'tcx>, arms: &[MatchArm<'p, 'tcx>], - scrut_hir_id: HirId, + lint_root: HirId, scrut_ty: Ty<'tcx>, ) -> UsefulnessReport<'p, 'tcx> { let mut matrix = Matrix::empty(); @@ -974,9 +986,9 @@ pub(crate) fn compute_match_usefulness<'p, 'tcx>( }) .collect(); - let wild_pattern = cx.pattern_arena.alloc(DeconstructedPat::wildcard(scrut_ty)); + let wild_pattern = cx.pattern_arena.alloc(DeconstructedPat::wildcard(scrut_ty, DUMMY_SP)); let v = PatStack::from_pattern(wild_pattern); - let usefulness = is_useful(cx, &matrix, &v, FakeExtraWildcard, scrut_hir_id, false, true); + let usefulness = is_useful(cx, &matrix, &v, FakeExtraWildcard, lint_root, false, true); let non_exhaustiveness_witnesses = match usefulness { WithWitnesses(pats) => pats.into_iter().map(|w| w.single_pattern()).collect(), NoWitnesses { .. } => bug!(), |