bjoernager/rust
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pattern_analysis doesn't need to know what spans are

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This commit is contained in:
Nadrieril 2023-12-15 16:18:21 +01:00
parent 8c5e89907c
commit 1e89a38423
6 changed files with 39 additions and 36 deletions
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10
compiler/rustc_pattern_analysis/src/usefulness.rs
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@ -849,7 +849,7 @@ impl<'a, 'p, Cx: MatchCx> Matrix<'a, 'p, Cx> {
scrut_validity: ValidityConstraint,
) -> Self {
let wild_pattern =
wildcard_arena.alloc(DeconstructedPat::wildcard(scrut_ty, Cx::Span::default()));
wildcard_arena.alloc(DeconstructedPat::wildcard(scrut_ty, Default::default()));
let wildcard_row = PatStack::from_pattern(wild_pattern);
let mut matrix = Matrix {
rows: Vec::with_capacity(arms.len()),
@ -1287,11 +1287,11 @@ fn compute_exhaustiveness_and_usefulness<'a, 'p, Cx: MatchCx>(
/// Indicates whether or not a given arm is useful.
#[derive(Clone, Debug)]
pub enum Usefulness<Span> {
pub enum Usefulness<'p, Cx: MatchCx> {
/// The arm is useful. This additionally carries a set of or-pattern branches that have been
/// found to be redundant despite the overall arm being useful. Used only in the presence of
/// or-patterns, otherwise it stays empty.
Useful(Vec<Span>),
Useful(Vec<&'p DeconstructedPat<'p, Cx>>),
/// The arm is redundant and can be removed without changing the behavior of the match
/// expression.
Redundant,
@ -1300,7 +1300,7 @@ pub enum Usefulness<Span> {
/// The output of checking a match for exhaustiveness and arm usefulness.
pub struct UsefulnessReport<'p, Cx: MatchCx> {
/// For each arm of the input, whether that arm is useful after the arms above it.
pub arm_usefulness: Vec<(MatchArm<'p, Cx>, Usefulness<Cx::Span>)>,
pub arm_usefulness: Vec<(MatchArm<'p, Cx>, Usefulness<'p, Cx>)>,
/// If the match is exhaustive, this is empty. If not, this contains witnesses for the lack of
/// exhaustiveness.
pub non_exhaustiveness_witnesses: Vec<WitnessPat<Cx>>,
@ -1327,7 +1327,7 @@ pub fn compute_match_usefulness<'p, Cx: MatchCx>(
debug!(?arm);
// We warn when a pattern is not useful.
let usefulness = if arm.pat.is_useful() {
Usefulness::Useful(arm.pat.redundant_spans())
Usefulness::Useful(arm.pat.redundant_subpatterns())
} else {
Usefulness::Redundant
};