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Fix significant drop detection

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This commit is contained in:
Ruihan Li 2024-04-26 17:26:35 +08:00
parent 20b085d500
commit a032189503
2 changed files with 42 additions and 28 deletions
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60
clippy_lints/src/matches/significant_drop_in_scrutinee.rs
View file

@ -119,41 +119,49 @@ impl<'a, 'tcx> SigDropChecker<'a, 'tcx> {
self.cx.typeck_results().expr_ty(ex)
}
fn has_seen_type(&mut self, ty: Ty<'tcx>) -> bool {
!self.seen_types.insert(ty)
fn has_sig_drop_attr(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
self.seen_types.clear();
self.has_sig_drop_attr_impl(cx, ty)
}
fn has_sig_drop_attr(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
fn has_sig_drop_attr_impl(&mut self, cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
if let Some(adt) = ty.ty_adt_def() {
if get_attr(cx.sess(), cx.tcx.get_attrs_unchecked(adt.did()), "has_significant_drop").count() > 0 {
return true;
}
}
match ty.kind() {
rustc_middle::ty::Adt(a, b) => {
for f in a.all_fields() {
let ty = f.ty(cx.tcx, b);
if !self.has_seen_type(ty) && self.has_sig_drop_attr(cx, ty) {
return true;
}
}
for generic_arg in *b {
if let GenericArgKind::Type(ty) = generic_arg.unpack() {
if self.has_sig_drop_attr(cx, ty) {
return true;
}
}
}
false
},
rustc_middle::ty::Array(ty, _)
| rustc_middle::ty::RawPtr(ty, _)
| rustc_middle::ty::Ref(_, ty, _)
| rustc_middle::ty::Slice(ty) => self.has_sig_drop_attr(cx, *ty),
_ => false,
if !self.seen_types.insert(ty) {
return false;
}
let result = match ty.kind() {
rustc_middle::ty::Adt(adt, args) => {
// if some field has significant drop,
adt.all_fields()
.map(|field| field.ty(cx.tcx, args))
.any(|ty| self.has_sig_drop_attr(cx, ty))
// or if there is no generic lifetime and..
// (to avoid false positive on `Ref<'a, MutexGuard<Foo>>`)
|| (args
.iter()
.all(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_)))
// some generic parameter has significant drop
// (to avoid false negative on `Box<MutexGuard<Foo>>`)
&& args
.iter()
.filter_map(|arg| match arg.unpack() {
GenericArgKind::Type(ty) => Some(ty),
_ => None,
})
.any(|ty| self.has_sig_drop_attr(cx, ty)))
},
rustc_middle::ty::Tuple(tys) => tys.iter().any(|ty| self.has_sig_drop_attr(cx, ty)),
rustc_middle::ty::Array(ty, _) | rustc_middle::ty::Slice(ty) => self.has_sig_drop_attr(cx, *ty),
_ => false,
};
result
}
}

10
tests/ui/significant_drop_in_scrutinee.stderr
View file

@ -28,6 +28,9 @@ LL | match s.lock_m().get_the_value() {
LL | println!("{}", s.lock_m().get_the_value());
| ---------- another value with significant `Drop` created here
...
LL | println!("{}", s.lock_m().get_the_value());
| ---------- another value with significant `Drop` created here
...
LL | }
| - temporary lives until here
|
@ -47,6 +50,9 @@ LL | match s.lock_m_m().get_the_value() {
LL | println!("{}", s.lock_m().get_the_value());
| ---------- another value with significant `Drop` created here
...
LL | println!("{}", s.lock_m().get_the_value());
| ---------- another value with significant `Drop` created here
...
LL | }
| - temporary lives until here
|
@ -360,7 +366,7 @@ LL | match s.lock().deref().deref() {
| ^^^^^^^^^^^^^^^^^^^^^^^^
...
LL | _ => println!("Value is {}", s.lock().deref()),
| ---------------- another value with significant `Drop` created here
| -------- another value with significant `Drop` created here
LL | };
| - temporary lives until here
|
@ -378,7 +384,7 @@ LL | match s.lock().deref().deref() {
| ^^^^^^^^^^^^^^^^^^^^^^^^
...
LL | matcher => println!("Value is {}", s.lock().deref()),
| ---------------- another value with significant `Drop` created here
| -------- another value with significant `Drop` created here
LL | _ => println!("Value was not a match"),
LL | };
| - temporary lives until here