diff options
Diffstat (limited to 'compiler/rustc_pattern_analysis/src/usefulness.rs')
| -rw-r--r-- | compiler/rustc_pattern_analysis/src/usefulness.rs | 79 |
1 files changed, 38 insertions, 41 deletions
diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs index b51b1a1f722..d2e621a6b98 100644 --- a/compiler/rustc_pattern_analysis/src/usefulness.rs +++ b/compiler/rustc_pattern_analysis/src/usefulness.rs @@ -821,22 +821,21 @@ impl fmt::Display for ValidityConstraint { /// Represents a pattern-tuple under investigation. // The three lifetimes are: -// - 'a allocated by us // - 'p coming from the input // - Cx global compilation context #[derive(derivative::Derivative)] #[derivative(Clone(bound = ""))] -struct PatStack<'a, 'p, Cx: TypeCx> { +struct PatStack<'p, Cx: TypeCx> { // Rows of len 1 are very common, which is why `SmallVec[_; 2]` works well. - pats: SmallVec<[&'a DeconstructedPat<'p, Cx>; 2]>, + pats: SmallVec<[&'p DeconstructedPat<'p, Cx>; 2]>, /// Sometimes we know that as far as this row is concerned, the current case is already handled /// by a different, more general, case. When the case is irrelevant for all rows this allows us /// to skip a case entirely. This is purely an optimization. See at the top for details. relevant: bool, } -impl<'a, 'p, Cx: TypeCx> PatStack<'a, 'p, Cx> { - fn from_pattern(pat: &'a DeconstructedPat<'p, Cx>) -> Self { +impl<'p, Cx: TypeCx> PatStack<'p, Cx> { + fn from_pattern(pat: &'p DeconstructedPat<'p, Cx>) -> Self { PatStack { pats: smallvec![pat], relevant: true } } @@ -848,17 +847,17 @@ impl<'a, 'p, Cx: TypeCx> PatStack<'a, 'p, Cx> { self.pats.len() } - fn head(&self) -> &'a DeconstructedPat<'p, Cx> { + fn head(&self) -> &'p DeconstructedPat<'p, Cx> { self.pats[0] } - fn iter<'b>(&'b self) -> impl Iterator<Item = &'a DeconstructedPat<'p, Cx>> + Captures<'b> { + fn iter(&self) -> impl Iterator<Item = &'p DeconstructedPat<'p, Cx>> + Captures<'_> { self.pats.iter().copied() } // Recursively expand the first or-pattern into its subpatterns. Only useful if the pattern is // an or-pattern. Panics if `self` is empty. - fn expand_or_pat<'b>(&'b self) -> impl Iterator<Item = PatStack<'a, 'p, Cx>> + Captures<'b> { + fn expand_or_pat(&self) -> impl Iterator<Item = PatStack<'p, Cx>> + Captures<'_> { self.head().flatten_or_pat().into_iter().map(move |pat| { let mut new = self.clone(); new.pats[0] = pat; @@ -870,10 +869,10 @@ impl<'a, 'p, Cx: TypeCx> PatStack<'a, 'p, Cx> { /// Only call if `ctor.is_covered_by(self.head().ctor())` is true. fn pop_head_constructor( &self, - pcx: &PlaceCtxt<'a, 'p, Cx>, + pcx: &PlaceCtxt<'_, 'p, Cx>, ctor: &Constructor<Cx>, ctor_is_relevant: bool, - ) -> PatStack<'a, 'p, Cx> { + ) -> PatStack<'p, Cx> { // We pop the head pattern and push the new fields extracted from the arguments of // `self.head()`. let mut new_pats = self.head().specialize(pcx, ctor); @@ -886,7 +885,7 @@ impl<'a, 'p, Cx: TypeCx> PatStack<'a, 'p, Cx> { } } -impl<'a, 'p, Cx: TypeCx> fmt::Debug for PatStack<'a, 'p, Cx> { +impl<'p, Cx: TypeCx> fmt::Debug for PatStack<'p, Cx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { // We pretty-print similarly to the `Debug` impl of `Matrix`. write!(f, "+")?; @@ -899,9 +898,9 @@ impl<'a, 'p, Cx: TypeCx> fmt::Debug for PatStack<'a, 'p, Cx> { /// A row of the matrix. #[derive(Clone)] -struct MatrixRow<'a, 'p, Cx: TypeCx> { +struct MatrixRow<'p, Cx: TypeCx> { // The patterns in the row. - pats: PatStack<'a, 'p, Cx>, + pats: PatStack<'p, Cx>, /// Whether the original arm had a guard. This is inherited when specializing. is_under_guard: bool, /// When we specialize, we remember which row of the original matrix produced a given row of the @@ -914,7 +913,7 @@ struct MatrixRow<'a, 'p, Cx: TypeCx> { useful: bool, } -impl<'a, 'p, Cx: TypeCx> MatrixRow<'a, 'p, Cx> { +impl<'p, Cx: TypeCx> MatrixRow<'p, Cx> { fn is_empty(&self) -> bool { self.pats.is_empty() } @@ -923,17 +922,17 @@ impl<'a, 'p, Cx: TypeCx> MatrixRow<'a, 'p, Cx> { self.pats.len() } - fn head(&self) -> &'a DeconstructedPat<'p, Cx> { + fn head(&self) -> &'p DeconstructedPat<'p, Cx> { self.pats.head() } - fn iter<'b>(&'b self) -> impl Iterator<Item = &'a DeconstructedPat<'p, Cx>> + Captures<'b> { + fn iter(&self) -> impl Iterator<Item = &'p DeconstructedPat<'p, Cx>> + Captures<'_> { self.pats.iter() } // Recursively expand the first or-pattern into its subpatterns. Only useful if the pattern is // an or-pattern. Panics if `self` is empty. - fn expand_or_pat<'b>(&'b self) -> impl Iterator<Item = MatrixRow<'a, 'p, Cx>> + Captures<'b> { + fn expand_or_pat(&self) -> impl Iterator<Item = MatrixRow<'p, Cx>> + Captures<'_> { self.pats.expand_or_pat().map(|patstack| MatrixRow { pats: patstack, parent_row: self.parent_row, @@ -946,11 +945,11 @@ impl<'a, 'p, Cx: TypeCx> MatrixRow<'a, 'p, Cx> { /// Only call if `ctor.is_covered_by(self.head().ctor())` is true. fn pop_head_constructor( &self, - pcx: &PlaceCtxt<'a, 'p, Cx>, + pcx: &PlaceCtxt<'_, 'p, Cx>, ctor: &Constructor<Cx>, ctor_is_relevant: bool, parent_row: usize, - ) -> MatrixRow<'a, 'p, Cx> { + ) -> MatrixRow<'p, Cx> { MatrixRow { pats: self.pats.pop_head_constructor(pcx, ctor, ctor_is_relevant), parent_row, @@ -960,7 +959,7 @@ impl<'a, 'p, Cx: TypeCx> MatrixRow<'a, 'p, Cx> { } } -impl<'a, 'p, Cx: TypeCx> fmt::Debug for MatrixRow<'a, 'p, Cx> { +impl<'p, Cx: TypeCx> fmt::Debug for MatrixRow<'p, Cx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { self.pats.fmt(f) } @@ -977,22 +976,22 @@ impl<'a, 'p, Cx: TypeCx> fmt::Debug for MatrixRow<'a, 'p, Cx> { /// specializing `(,)` and `Some` on a pattern of type `(Option<u32>, bool)`, the first column of /// the matrix will correspond to `scrutinee.0.Some.0` and the second column to `scrutinee.1`. #[derive(Clone)] -struct Matrix<'a, 'p, Cx: TypeCx> { +struct Matrix<'p, Cx: TypeCx> { /// Vector of rows. The rows must form a rectangular 2D array. Moreover, all the patterns of /// each column must have the same type. Each column corresponds to a place within the /// scrutinee. - rows: Vec<MatrixRow<'a, 'p, Cx>>, + rows: Vec<MatrixRow<'p, Cx>>, /// Stores an extra fictitious row full of wildcards. Mostly used to keep track of the type of /// each column. This must obey the same invariants as the real rows. - wildcard_row: PatStack<'a, 'p, Cx>, + wildcard_row: PatStack<'p, Cx>, /// Track for each column/place whether it contains a known valid value. place_validity: SmallVec<[ValidityConstraint; 2]>, } -impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { +impl<'p, Cx: TypeCx> Matrix<'p, Cx> { /// Pushes a new row to the matrix. If the row starts with an or-pattern, this recursively /// expands it. Internal method, prefer [`Matrix::new`]. - fn expand_and_push(&mut self, row: MatrixRow<'a, 'p, Cx>) { + fn expand_and_push(&mut self, row: MatrixRow<'p, Cx>) { if !row.is_empty() && row.head().is_or_pat() { // Expand nested or-patterns. for new_row in row.expand_or_pat() { @@ -1005,8 +1004,8 @@ impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { /// Build a new matrix from an iterator of `MatchArm`s. fn new( - wildcard_arena: &'a TypedArena<DeconstructedPat<'p, Cx>>, - arms: &'a [MatchArm<'p, Cx>], + wildcard_arena: &'p TypedArena<DeconstructedPat<'p, Cx>>, + arms: &[MatchArm<'p, Cx>], scrut_ty: Cx::Ty, scrut_validity: ValidityConstraint, ) -> Self { @@ -1029,7 +1028,7 @@ impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { matrix } - fn head_ty(&self, mcx: MatchCtxt<'a, 'p, Cx>) -> Option<Cx::Ty> { + fn head_ty(&self, mcx: MatchCtxt<'_, 'p, Cx>) -> Option<Cx::Ty> { if self.column_count() == 0 { return None; } @@ -1042,33 +1041,31 @@ impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { self.wildcard_row.len() } - fn rows<'b>( - &'b self, - ) -> impl Iterator<Item = &'b MatrixRow<'a, 'p, Cx>> + Clone + DoubleEndedIterator + ExactSizeIterator + fn rows( + &self, + ) -> impl Iterator<Item = &MatrixRow<'p, Cx>> + Clone + DoubleEndedIterator + ExactSizeIterator { self.rows.iter() } - fn rows_mut<'b>( - &'b mut self, - ) -> impl Iterator<Item = &'b mut MatrixRow<'a, 'p, Cx>> + DoubleEndedIterator + ExactSizeIterator + fn rows_mut( + &mut self, + ) -> impl Iterator<Item = &mut MatrixRow<'p, Cx>> + DoubleEndedIterator + ExactSizeIterator { self.rows.iter_mut() } /// Iterate over the first pattern of each row. - fn heads<'b>( - &'b self, - ) -> impl Iterator<Item = &'b DeconstructedPat<'p, Cx>> + Clone + Captures<'a> { + fn heads(&self) -> impl Iterator<Item = &'p DeconstructedPat<'p, Cx>> + Clone + Captures<'_> { self.rows().map(|r| r.head()) } /// This computes `specialize(ctor, self)`. See top of the file for explanations. fn specialize_constructor( &self, - pcx: &PlaceCtxt<'a, 'p, Cx>, + pcx: &PlaceCtxt<'_, 'p, Cx>, ctor: &Constructor<Cx>, ctor_is_relevant: bool, - ) -> Matrix<'a, 'p, Cx> { + ) -> Matrix<'p, Cx> { let wildcard_row = self.wildcard_row.pop_head_constructor(pcx, ctor, ctor_is_relevant); let new_validity = self.place_validity[0].specialize(ctor); let new_place_validity = std::iter::repeat(new_validity) @@ -1097,7 +1094,7 @@ impl<'a, 'p, Cx: TypeCx> Matrix<'a, 'p, Cx> { /// + _ + [_, _, tail @ ..] + /// | ✓ | ? | // column validity /// ``` -impl<'a, 'p, Cx: TypeCx> fmt::Debug for Matrix<'a, 'p, Cx> { +impl<'p, Cx: TypeCx> fmt::Debug for Matrix<'p, Cx> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "\n")?; @@ -1336,7 +1333,7 @@ impl<Cx: TypeCx> WitnessMatrix<Cx> { #[instrument(level = "debug", skip(mcx, is_top_level), ret)] fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: TypeCx>( mcx: MatchCtxt<'a, 'p, Cx>, - matrix: &mut Matrix<'a, 'p, Cx>, + matrix: &mut Matrix<'p, Cx>, is_top_level: bool, ) -> WitnessMatrix<Cx> { debug_assert!(matrix.rows().all(|r| r.len() == matrix.column_count())); |