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borrowck nested items in dead code

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This commit is contained in:
lcnr
2025-05-02 16:24:28 +00:00
parent f97b3c6044
commit ffa7d1ee5d
11 changed files with 135 additions and 64 deletions
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8
compiler/rustc_borrowck/src/lib.rs
View File

@@ -127,6 +127,14 @@ fn mir_borrowck(
Ok(tcx.arena.alloc(opaque_types))
} else {
let mut root_cx = BorrowCheckRootCtxt::new(tcx, def);
// We need to manually borrowck all nested bodies from the HIR as
// we do not generate MIR for dead code. Not doing so causes us to
// never check closures in dead code.
let nested_bodies = tcx.nested_bodies_within(def);
for def_id in nested_bodies {
root_cx.get_or_insert_nested(def_id);
}
let PropagatedBorrowCheckResults { closure_requirements, used_mut_upvars } =
do_mir_borrowck(&mut root_cx, def, None).0;
debug_assert!(closure_requirements.is_none());

5
compiler/rustc_borrowck/src/root_cx.rs
View File

@@ -62,7 +62,10 @@ impl<'tcx> BorrowCheckRootCtxt<'tcx> {
self.tainted_by_errors = Some(guar);
}
fn get_or_insert_nested(&mut self, def_id: LocalDefId) -> &PropagatedBorrowCheckResults<'tcx> {
pub(super) fn get_or_insert_nested(
&mut self,
def_id: LocalDefId,
) -> &PropagatedBorrowCheckResults<'tcx> {
debug_assert_eq!(
self.tcx.typeck_root_def_id(def_id.to_def_id()),
self.root_def_id.to_def_id()

2
compiler/rustc_middle/src/query/mod.rs
View File

@@ -387,7 +387,7 @@ rustc_queries! {
}
}
query stalled_generators_within(
query nested_bodies_within(
key: LocalDefId
) -> &'tcx ty::List<LocalDefId> {
desc {

10
compiler/rustc_middle/src/ty/context.rs
View File

@@ -684,15 +684,17 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
self.opaque_types_defined_by(defining_anchor)
}
fn opaque_types_and_generators_defined_by(
fn opaque_types_and_coroutines_defined_by(
self,
defining_anchor: Self::LocalDefId,
) -> Self::LocalDefIds {
if self.next_trait_solver_globally() {
let coroutines_defined_by = self
.nested_bodies_within(defining_anchor)
.iter()
.filter(|def_id| self.is_coroutine(def_id.to_def_id()));
self.mk_local_def_ids_from_iter(
self.opaque_types_defined_by(defining_anchor)
.iter()
.chain(self.stalled_generators_within(defining_anchor)),
self.opaque_types_defined_by(defining_anchor).iter().chain(coroutines_defined_by),
)
} else {
self.opaque_types_defined_by(defining_anchor)

4
compiler/rustc_ty_utils/src/lib.rs
View File

@@ -29,10 +29,10 @@ mod implied_bounds;
mod instance;
mod layout;
mod needs_drop;
mod nested_bodies;
mod opaque_types;
mod representability;
pub mod sig_types;
mod stalled_generators;
mod structural_match;
mod ty;
@@ -51,5 +51,5 @@ pub fn provide(providers: &mut Providers) {
ty::provide(providers);
instance::provide(providers);
structural_match::provide(providers);
stalled_generators::provide(providers);
nested_bodies::provide(providers);
}

34
compiler/rustc_ty_utils/src/nested_bodies.rs Normal file
View File

@@ -0,0 +1,34 @@
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::Visitor;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt};
fn nested_bodies_within<'tcx>(tcx: TyCtxt<'tcx>, item: LocalDefId) -> &'tcx ty::List<LocalDefId> {
let body = tcx.hir_body_owned_by(item);
let mut collector =
NestedBodiesVisitor { tcx, root_def_id: item.to_def_id(), nested_bodies: vec![] };
collector.visit_body(body);
tcx.mk_local_def_ids(&collector.nested_bodies)
}
struct NestedBodiesVisitor<'tcx> {
tcx: TyCtxt<'tcx>,
root_def_id: DefId,
nested_bodies: Vec<LocalDefId>,
}
impl<'tcx> Visitor<'tcx> for NestedBodiesVisitor<'tcx> {
fn visit_nested_body(&mut self, id: hir::BodyId) {
let body_def_id = self.tcx.hir_body_owner_def_id(id);
if self.tcx.typeck_root_def_id(body_def_id.to_def_id()) == self.root_def_id {
self.nested_bodies.push(body_def_id);
let body = self.tcx.hir_body(id);
self.visit_body(body);
}
}
}
pub(super) fn provide(providers: &mut Providers) {
*providers = Providers { nested_bodies_within, ..*providers };
}

54
compiler/rustc_ty_utils/src/stalled_generators.rs
View File

@@ -1,54 +0,0 @@
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit;
use rustc_hir::intravisit::Visitor;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt};
fn stalled_generators_within<'tcx>(
tcx: TyCtxt<'tcx>,
item: LocalDefId,
) -> &'tcx ty::List<LocalDefId> {
if !tcx.next_trait_solver_globally() {
return ty::List::empty();
}
let body = tcx.hir_body_owned_by(item);
let mut collector =
StalledGeneratorVisitor { tcx, root_def_id: item.to_def_id(), stalled_coroutines: vec![] };
collector.visit_body(body);
tcx.mk_local_def_ids(&collector.stalled_coroutines)
}
struct StalledGeneratorVisitor<'tcx> {
tcx: TyCtxt<'tcx>,
root_def_id: DefId,
stalled_coroutines: Vec<LocalDefId>,
}
impl<'tcx> Visitor<'tcx> for StalledGeneratorVisitor<'tcx> {
fn visit_nested_body(&mut self, id: hir::BodyId) {
if self.tcx.typeck_root_def_id(self.tcx.hir_body_owner_def_id(id).to_def_id())
== self.root_def_id
{
let body = self.tcx.hir_body(id);
self.visit_body(body);
}
}
fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
if let hir::ExprKind::Closure(&hir::Closure {
def_id,
kind: hir::ClosureKind::Coroutine(_),
..
}) = ex.kind
{
self.stalled_coroutines.push(def_id);
}
intravisit::walk_expr(self, ex);
}
}
pub(super) fn provide(providers: &mut Providers) {
*providers = Providers { stalled_generators_within, ..*providers };
}

2
compiler/rustc_type_ir/src/infer_ctxt.rs
View File

@@ -100,7 +100,7 @@ impl<I: Interner> TypingMode<I> {
pub fn typeck_for_body(cx: I, body_def_id: I::LocalDefId) -> TypingMode<I> {
TypingMode::Analysis {
defining_opaque_types_and_generators: cx
.opaque_types_and_generators_defined_by(body_def_id),
.opaque_types_and_coroutines_defined_by(body_def_id),
}
}

2
compiler/rustc_type_ir/src/interner.rs
View File

@@ -341,7 +341,7 @@ pub trait Interner:
fn opaque_types_defined_by(self, defining_anchor: Self::LocalDefId) -> Self::LocalDefIds;
fn opaque_types_and_generators_defined_by(
fn opaque_types_and_coroutines_defined_by(
self,
defining_anchor: Self::LocalDefId,
) -> Self::LocalDefIds;

28
tests/ui/nll/nested-bodies-in-dead-code.rs Normal file
View File

@@ -0,0 +1,28 @@
//@ edition: 2024
// Regression test for #140583. We want to borrowck nested
// bodies even if they are in dead code. While not necessary for
// soundness, it is desirable to error in such cases.
fn main() {
return;
|x: &str| -> &'static str { x };
//~^ ERROR lifetime may not live long enough
|| {
|| {
let temp = 1;
let p: &'static u32 = &temp;
//~^ ERROR `temp` does not live long enough
};
};
const {
let temp = 1;
let p: &'static u32 = &temp;
//~^ ERROR `temp` does not live long enough
};
async {
let temp = 1;
let p: &'static u32 = &temp;
//~^ ERROR `temp` does not live long enough
};
}

50
tests/ui/nll/nested-bodies-in-dead-code.stderr Normal file
View File

@@ -0,0 +1,50 @@
error: lifetime may not live long enough
--> $DIR/nested-bodies-in-dead-code.rs:9:33
|
LL | |x: &str| -> &'static str { x };
| - ^ returning this value requires that `'1` must outlive `'static`
| |
| let's call the lifetime of this reference `'1`
error[E0597]: `temp` does not live long enough
--> $DIR/nested-bodies-in-dead-code.rs:14:35
|
LL | let temp = 1;
| ---- binding `temp` declared here
LL | let p: &'static u32 = &temp;
| ------------ ^^^^^ borrowed value does not live long enough
| |
| type annotation requires that `temp` is borrowed for `'static`
LL |
LL | };
| - `temp` dropped here while still borrowed
error[E0597]: `temp` does not live long enough
--> $DIR/nested-bodies-in-dead-code.rs:20:31
|
LL | let temp = 1;
| ---- binding `temp` declared here
LL | let p: &'static u32 = &temp;
| ------------ ^^^^^ borrowed value does not live long enough
| |
| type annotation requires that `temp` is borrowed for `'static`
LL |
LL | };
| - `temp` dropped here while still borrowed
error[E0597]: `temp` does not live long enough
--> $DIR/nested-bodies-in-dead-code.rs:25:31
|
LL | let temp = 1;
| ---- binding `temp` declared here
LL | let p: &'static u32 = &temp;
| ------------ ^^^^^ borrowed value does not live long enough
| |
| type annotation requires that `temp` is borrowed for `'static`
LL |
LL | };
| - `temp` dropped here while still borrowed
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0597`.