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 | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs index 0a660ef30..115d34ff8 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/usefulness.rs @@ -364,8 +364,8 @@ impl<'a, 'p, 'tcx> fmt::Debug for PatCtxt<'a, 'p, 'tcx> { /// A row of a matrix. Rows of len 1 are very common, which is why `SmallVec[_; 2]` /// works well. #[derive(Clone)] -struct PatStack<'p, 'tcx> { - pats: SmallVec<[&'p DeconstructedPat<'p, 'tcx>; 2]>, +pub(crate) struct PatStack<'p, 'tcx> { + pub(crate) pats: SmallVec<[&'p DeconstructedPat<'p, 'tcx>; 2]>, } impl<'p, 'tcx> PatStack<'p, 'tcx> { @@ -403,6 +403,21 @@ impl<'p, 'tcx> PatStack<'p, 'tcx> { }) } + // Recursively expand all patterns into their subpatterns and push each `PatStack` to matrix. + fn expand_and_extend<'a>(&'a self, matrix: &mut Matrix<'p, 'tcx>) { + if !self.is_empty() && self.head().is_or_pat() { + for pat in self.head().iter_fields() { + let mut new_patstack = PatStack::from_pattern(pat); + new_patstack.pats.extend_from_slice(&self.pats[1..]); + if !new_patstack.is_empty() && new_patstack.head().is_or_pat() { + new_patstack.expand_and_extend(matrix); + } else if !new_patstack.is_empty() { + matrix.push(new_patstack); + } + } + } + } + /// This computes `S(self.head().ctor(), self)`. See top of the file for explanations. /// /// Structure patterns with a partial wild pattern (Foo { a: 42, .. }) have their missing @@ -436,7 +451,7 @@ impl<'p, 'tcx> fmt::Debug for PatStack<'p, 'tcx> { /// A 2D matrix. #[derive(Clone)] pub(super) struct Matrix<'p, 'tcx> { - patterns: Vec<PatStack<'p, 'tcx>>, + pub patterns: Vec<PatStack<'p, 'tcx>>, } impl<'p, 'tcx> Matrix<'p, 'tcx> { @@ -453,7 +468,7 @@ impl<'p, 'tcx> Matrix<'p, 'tcx> { /// expands it. fn push(&mut self, row: PatStack<'p, 'tcx>) { if !row.is_empty() && row.head().is_or_pat() { - self.patterns.extend(row.expand_or_pat()); + row.expand_and_extend(self); } else { self.patterns.push(row); } @@ -739,8 +754,8 @@ fn lint_non_exhaustive_omitted_patterns<'p, 'tcx>( hir_id: HirId, witnesses: Vec<DeconstructedPat<'p, 'tcx>>, ) { - let joined_patterns = joined_uncovered_patterns(cx, &witnesses); cx.tcx.struct_span_lint_hir(NON_EXHAUSTIVE_OMITTED_PATTERNS, hir_id, sp, |build| { + let joined_patterns = joined_uncovered_patterns(cx, &witnesses); let mut lint = build.build("some variants are not matched explicitly"); lint.span_label(sp, pattern_not_covered_label(&witnesses, &joined_patterns)); lint.help( @@ -776,7 +791,7 @@ fn lint_non_exhaustive_omitted_patterns<'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))] +#[instrument(level = "debug", skip(cx, matrix, hir_id), ret)] fn is_useful<'p, 'tcx>( cx: &MatchCheckCtxt<'p, 'tcx>, matrix: &Matrix<'p, 'tcx>, @@ -902,7 +917,6 @@ fn is_useful<'p, 'tcx>( v.head().set_reachable(); } - debug!(?ret); ret } |