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Only one caller of lower_match_tree was using the fake borrows

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This commit is contained in:
Nadrieril 2024-06-17 19:29:14 +02:00
parent ea29d6ad0b
commit 012626b32b
1 changed files with 17 additions and 31 deletions
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48
compiler/rustc_mir_build/src/build/matches/mod.rs
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@ -315,12 +315,19 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let match_start_span = span.shrink_to_lo().to(scrutinee_span);
let fake_borrow_temps = self.lower_match_tree(
// The set of places that we are creating fake borrows of. If there are no match guards then
// we don't need any fake borrows, so don't track them.
let fake_borrow_temps: Vec<(Place<'tcx>, Local, FakeBorrowKind)> = if match_has_guard {
util::collect_fake_borrows(self, &candidates, scrutinee_span, scrutinee_place.base())
} else {
Vec::new()
};
self.lower_match_tree(
block,
scrutinee_span,
&scrutinee_place,
match_start_span,
match_has_guard,
&mut candidates,
);
@ -377,30 +384,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
///
/// Modifies `candidates` to store the bindings and type ascriptions for
/// that candidate.
///
/// Returns the places that need fake borrows because we bind or test them.
fn lower_match_tree<'pat>(
&mut self,
block: BasicBlock,
scrutinee_span: Span,
scrutinee_place_builder: &PlaceBuilder<'tcx>,
match_start_span: Span,
match_has_guard: bool,
candidates: &mut [&mut Candidate<'pat, 'tcx>],
) -> Vec<(Place<'tcx>, Local, FakeBorrowKind)> {
// The set of places that we are creating fake borrows of. If there are no match guards then
// we don't need any fake borrows, so don't track them.
let fake_borrows: Vec<(Place<'tcx>, Local, FakeBorrowKind)> = if match_has_guard {
util::collect_fake_borrows(
self,
candidates,
scrutinee_span,
scrutinee_place_builder.base(),
)
} else {
Vec::new()
};
) {
// See the doc comment on `match_candidates` for why we have an
// otherwise block. Match checking will ensure this is actually
// unreachable.
@ -452,8 +443,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
previous_candidate = Some(leaf_candidate);
});
}
fake_borrows
}
/// Lower the bindings, guards and arm bodies of a `match` expression.
@ -761,18 +750,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
}
let fake_borrow_temps = self.lower_match_tree(
self.lower_match_tree(
block,
irrefutable_pat.span,
&initializer,
irrefutable_pat.span,
false,
&mut [&mut candidate],
);
self.bind_pattern(
self.source_info(irrefutable_pat.span),
candidate,
fake_borrow_temps.as_slice(),
&[],
irrefutable_pat.span,
None,
false,
@ -1995,12 +1983,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let mut guard_candidate = Candidate::new(expr_place_builder.clone(), pat, false, self);
let mut otherwise_candidate =
Candidate::new(expr_place_builder.clone(), &wildcard, false, self);
let fake_borrow_temps = self.lower_match_tree(
self.lower_match_tree(
block,
pat.span,
&expr_place_builder,
pat.span,
false,
&mut [&mut guard_candidate, &mut otherwise_candidate],
);
let expr_place = expr_place_builder.try_to_place(self);
@ -2015,7 +2002,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let post_guard_block = self.bind_pattern(
self.source_info(pat.span),
guard_candidate,
fake_borrow_temps.as_slice(),
&[],
expr_span,
None,
false,
@ -2490,19 +2477,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let pat = Pat { ty: pattern.ty, span: else_block_span, kind: PatKind::Wild };
let mut wildcard = Candidate::new(scrutinee.clone(), &pat, false, this);
let mut candidate = Candidate::new(scrutinee.clone(), pattern, false, this);
let fake_borrow_temps = this.lower_match_tree(
this.lower_match_tree(
block,
initializer_span,
&scrutinee,
pattern.span,
false,
&mut [&mut candidate, &mut wildcard],
);
// This block is for the matching case
let matching = this.bind_pattern(
this.source_info(pattern.span),
candidate,
fake_borrow_temps.as_slice(),
&[],
initializer_span,
None,
true,
@ -2511,7 +2497,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let failure = this.bind_pattern(
this.source_info(else_block_span),
wildcard,
fake_borrow_temps.as_slice(),
&[],
initializer_span,
None,
true,