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Use more let_else in rustc_mir_build
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Helps avoid rightward drift.
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@est31
est31 committed Nov 18, 2021
1 parent 6414e0b commit 8dc8e72
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Showing 3 changed files with 66 additions and 69 deletions.
11 changes: 5 additions & 6 deletions compiler/rustc_mir_build/src/build/matches/mod.rs
View file
Expand Up @@ -1606,13 +1606,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
// encounter a candidate where the test is not relevant; at
// that point, we stop sorting.
while let Some(candidate) = candidates.first_mut() {
if let Some(idx) = self.sort_candidate(&match_place.clone(), &test, candidate) {
let (candidate, rest) = candidates.split_first_mut().unwrap();
target_candidates[idx].push(candidate);
candidates = rest;
} else {
let Some(idx) = self.sort_candidate(&match_place.clone(), &test, candidate) else {
break;
}
};
let (candidate, rest) = candidates.split_first_mut().unwrap();
target_candidates[idx].push(candidate);
candidates = rest;
}
// at least the first candidate ought to be tested
assert!(total_candidate_count > candidates.len());
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101 changes: 50 additions & 51 deletions compiler/rustc_mir_build/src/build/mod.rs
View file
Expand Up @@ -966,59 +966,58 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
DropKind::Value,
);

if let Some(arg) = arg_opt {
let pat = match tcx.hir().get(arg.pat.hir_id) {
Node::Pat(pat) | Node::Binding(pat) => pat,
node => bug!("pattern became {:?}", node),
};
let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
let original_source_scope = self.source_scope;
let span = pattern.span;
self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
match *pattern.kind {
// Don't introduce extra copies for simple bindings
PatKind::Binding {
mutability,
var,
mode: BindingMode::ByValue,
subpattern: None,
..
} => {
self.local_decls[local].mutability = mutability;
self.local_decls[local].source_info.scope = self.source_scope;
self.local_decls[local].local_info = if let Some(kind) = self_binding {
Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
BindingForm::ImplicitSelf(*kind),
))))
} else {
let binding_mode = ty::BindingMode::BindByValue(mutability);
Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
VarBindingForm {
binding_mode,
opt_ty_info,
opt_match_place: Some((Some(place), span)),
pat_span: span,
},
)))))
};
self.var_indices.insert(var, LocalsForNode::One(local));
}
_ => {
scope = self.declare_bindings(
scope,
expr.span,
&pattern,
matches::ArmHasGuard(false),
Some((Some(&place), span)),
);
let place_builder = PlaceBuilder::from(local);
unpack!(
block = self.place_into_pattern(block, pattern, place_builder, false)
);
}
let Some(arg) = arg_opt else {
continue;
};
let pat = match tcx.hir().get(arg.pat.hir_id) {
Node::Pat(pat) | Node::Binding(pat) => pat,
node => bug!("pattern became {:?}", node),
};
let pattern = pat_from_hir(tcx, self.param_env, self.typeck_results, pat);
let original_source_scope = self.source_scope;
let span = pattern.span;
self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
match *pattern.kind {
// Don't introduce extra copies for simple bindings
PatKind::Binding {
mutability,
var,
mode: BindingMode::ByValue,
subpattern: None,
..
} => {
self.local_decls[local].mutability = mutability;
self.local_decls[local].source_info.scope = self.source_scope;
self.local_decls[local].local_info = if let Some(kind) = self_binding {
Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(
BindingForm::ImplicitSelf(*kind),
))))
} else {
let binding_mode = ty::BindingMode::BindByValue(mutability);
Some(Box::new(LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
VarBindingForm {
binding_mode,
opt_ty_info,
opt_match_place: Some((Some(place), span)),
pat_span: span,
},
)))))
};
self.var_indices.insert(var, LocalsForNode::One(local));
}
_ => {
scope = self.declare_bindings(
scope,
expr.span,
&pattern,
matches::ArmHasGuard(false),
Some((Some(&place), span)),
);
let place_builder = PlaceBuilder::from(local);
unpack!(block = self.place_into_pattern(block, pattern, place_builder, false));
}
self.source_scope = original_source_scope;
}
self.source_scope = original_source_scope;
}

// Enter the argument pattern bindings source scope, if it exists.
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23 changes: 11 additions & 12 deletions compiler/rustc_mir_build/src/check_unsafety.rs
View file
Expand Up @@ -256,23 +256,22 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
}
PatKind::Binding { mode: BindingMode::ByRef(borrow_kind), ty, .. } => {
if self.inside_adt {
if let ty::Ref(_, ty, _) = ty.kind() {
match borrow_kind {
BorrowKind::Shallow | BorrowKind::Shared | BorrowKind::Unique => {
if !ty.is_freeze(self.tcx.at(pat.span), self.param_env) {
self.requires_unsafe(pat.span, BorrowOfLayoutConstrainedField);
}
}
BorrowKind::Mut { .. } => {
self.requires_unsafe(pat.span, MutationOfLayoutConstrainedField);
}
}
} else {
let ty::Ref(_, ty, _) = ty.kind() else {
span_bug!(
pat.span,
"BindingMode::ByRef in pattern, but found non-reference type {}",
ty
);
};
match borrow_kind {
BorrowKind::Shallow | BorrowKind::Shared | BorrowKind::Unique => {
if !ty.is_freeze(self.tcx.at(pat.span), self.param_env) {
self.requires_unsafe(pat.span, BorrowOfLayoutConstrainedField);
}
}
BorrowKind::Mut { .. } => {
self.requires_unsafe(pat.span, MutationOfLayoutConstrainedField);
}
}
}
visit::walk_pat(self, pat);
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