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Use the correct span for simplifying or-patterns

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We have to make sure we set it everywhere that we set `subcandidates`.
This commit is contained in:
Nadrieril 2024-03-05 21:51:22 +01:00
parent 60b5ca6275
commit 08d7379961
2 changed files with 15 additions and 9 deletions
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21
compiler/rustc_mir_build/src/build/matches/mod.rs
View File

@ -1006,6 +1006,10 @@ struct Candidate<'pat, 'tcx> {
/// If the candidate matches, bindings and ascriptions must be established.
extra_data: PatternExtraData<'tcx>,
/// If we filled `self.subcandidate`, we store here the span of the or-pattern they came from.
// Invariant: it is `None` iff `subcandidates.is_empty()`.
or_span: Option<Span>,
/// The block before the `bindings` have been established.
pre_binding_block: Option<BasicBlock>,
/// The pre-binding block of the next candidate.
@ -1028,6 +1032,7 @@ impl<'tcx, 'pat> Candidate<'pat, 'tcx> {
extra_data: flat_pat.extra_data,
has_guard,
subcandidates: Vec::new(),
or_span: None,
otherwise_block: None,
pre_binding_block: None,
next_candidate_pre_binding_block: None,
@ -1277,7 +1282,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
//
// only generates a single switch.
candidate.subcandidates = self.create_or_subcandidates(pats, candidate.has_guard);
candidate.match_pairs.pop();
let first_match_pair = candidate.match_pairs.pop().unwrap();
candidate.or_span = Some(first_match_pair.pattern.span);
split_or_candidate = true;
}
}
@ -1531,16 +1537,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
&mut or_candidate_refs,
);
candidate.subcandidates = or_candidates;
self.merge_trivial_subcandidates(candidate, self.source_info(or_span));
candidate.or_span = Some(or_span);
self.merge_trivial_subcandidates(candidate);
}
/// Try to merge all of the subcandidates of the given candidate into one.
/// This avoids exponentially large CFGs in cases like `(1 | 2, 3 | 4, ...)`.
fn merge_trivial_subcandidates(
&mut self,
candidate: &mut Candidate<'_, 'tcx>,
source_info: SourceInfo,
) {
fn merge_trivial_subcandidates(&mut self, candidate: &mut Candidate<'_, 'tcx>) {
if candidate.subcandidates.is_empty() || candidate.has_guard {
// FIXME(or_patterns; matthewjasper) Don't give up if we have a guard.
return;
@ -1550,7 +1553,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
// Not `Iterator::all` because we don't want to short-circuit.
for subcandidate in &mut candidate.subcandidates {
self.merge_trivial_subcandidates(subcandidate, source_info);
self.merge_trivial_subcandidates(subcandidate);
// FIXME(or_patterns; matthewjasper) Try to be more aggressive here.
can_merge &=
@ -1559,6 +1562,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
if can_merge {
let any_matches = self.cfg.start_new_block();
let or_span = candidate.or_span.take().unwrap();
let source_info = self.source_info(or_span);
for subcandidate in mem::take(&mut candidate.subcandidates) {
let or_block = subcandidate.pre_binding_block.unwrap();
self.cfg.goto(or_block, source_info, any_matches);

3
compiler/rustc_mir_build/src/build/matches/simplify.rs
View File

@ -82,7 +82,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
&*candidate.match_pairs
{
candidate.subcandidates = self.create_or_subcandidates(pats, has_guard);
candidate.match_pairs.pop();
let first_match_pair = candidate.match_pairs.pop().unwrap();
candidate.or_span = Some(first_match_pair.pattern.span);
}
candidate
})