diff --git a/compiler/rustc_typeck/src/check/generator_interior.rs b/compiler/rustc_typeck/src/check/generator_interior.rs index d4f8001493c8b..85a0d4e449906 100644 --- a/compiler/rustc_typeck/src/check/generator_interior.rs +++ b/compiler/rustc_typeck/src/check/generator_interior.rs @@ -457,7 +457,7 @@ impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> { } #[derive(Default)] -pub struct SuspendCheckData<'a, 'tcx> { +struct SuspendCheckData<'a, 'tcx> { expr: Option<&'tcx Expr<'tcx>>, source_span: Span, yield_span: Span, @@ -472,7 +472,7 @@ pub struct SuspendCheckData<'a, 'tcx> { // // Note that this technique was chosen over things like a `Suspend` marker trait // as it is simpler and has precedent in the compiler -pub fn check_must_not_suspend_ty<'tcx>( +fn check_must_not_suspend_ty<'tcx>( fcx: &FnCtxt<'_, 'tcx>, ty: Ty<'tcx>, hir_id: HirId, @@ -489,6 +489,8 @@ pub fn check_must_not_suspend_ty<'tcx>( let plural_suffix = pluralize!(data.plural_len); + debug!("Checking must_not_suspend for {}", ty); + match *ty.kind() { ty::Adt(..) if ty.is_box() => { let boxed_ty = ty.boxed_ty(); @@ -580,6 +582,12 @@ pub fn check_must_not_suspend_ty<'tcx>( }, ) } + // If drop tracking is enabled, we want to look through references, since the referrent + // may not be considered live across the await point. + ty::Ref(_region, ty, _mutability) if fcx.sess().opts.unstable_opts.drop_tracking => { + let descr_pre = &format!("{}reference{} to ", data.descr_pre, plural_suffix); + check_must_not_suspend_ty(fcx, ty, hir_id, SuspendCheckData { descr_pre, ..data }) + } _ => false, } } diff --git a/src/test/ui/lint/must_not_suspend/ref-drop-tracking.rs b/src/test/ui/lint/must_not_suspend/ref-drop-tracking.rs new file mode 100644 index 0000000000000..1bc4a38125753 --- /dev/null +++ b/src/test/ui/lint/must_not_suspend/ref-drop-tracking.rs @@ -0,0 +1,30 @@ +// edition:2018 +// compile-flags: -Zdrop-tracking +#![feature(must_not_suspend)] +#![deny(must_not_suspend)] + +#[must_not_suspend = "You gotta use Umm's, ya know?"] +struct Umm { + i: i64 +} + +struct Bar { + u: Umm, +} + +async fn other() {} + +impl Bar { + async fn uhoh(&mut self) { + let guard = &mut self.u; //~ ERROR `Umm` held across + + other().await; + + *guard = Umm { + i: 2 + } + } +} + +fn main() { +} diff --git a/src/test/ui/lint/must_not_suspend/ref-drop-tracking.stderr b/src/test/ui/lint/must_not_suspend/ref-drop-tracking.stderr new file mode 100644 index 0000000000000..c49d271285371 --- /dev/null +++ b/src/test/ui/lint/must_not_suspend/ref-drop-tracking.stderr @@ -0,0 +1,27 @@ +error: reference to `Umm` held across a suspend point, but should not be + --> $DIR/ref-drop-tracking.rs:19:13 + | +LL | let guard = &mut self.u; + | ^^^^^ +LL | +LL | other().await; + | ------ the value is held across this suspend point + | +note: the lint level is defined here + --> $DIR/ref-drop-tracking.rs:4:9 + | +LL | #![deny(must_not_suspend)] + | ^^^^^^^^^^^^^^^^ +note: You gotta use Umm's, ya know? + --> $DIR/ref-drop-tracking.rs:19:13 + | +LL | let guard = &mut self.u; + | ^^^^^ +help: consider using a block (`{ ... }`) to shrink the value's scope, ending before the suspend point + --> $DIR/ref-drop-tracking.rs:19:13 + | +LL | let guard = &mut self.u; + | ^^^^^ + +error: aborting due to previous error +