diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs index ccc6644923ae6..be51fc7045493 100644 --- a/compiler/rustc_ast_lowering/src/expr.rs +++ b/compiler/rustc_ast_lowering/src/expr.rs @@ -632,17 +632,27 @@ impl<'hir> LoweringContext<'_, 'hir> { ) -> hir::ExprKind<'hir> { let output = ret_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span))); - // Resume argument type: `ResumeTy` - let unstable_span = self.mark_span_with_reason( - DesugaringKind::Async, - self.lower_span(span), - Some(self.allow_gen_future.clone()), - ); - let resume_ty = self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span); + // Resume argument type: `&mut Context<'_>`. + let context_lifetime_ident = Ident::with_dummy_span(kw::UnderscoreLifetime); + let context_lifetime = self.arena.alloc(hir::Lifetime { + hir_id: self.next_id(), + ident: context_lifetime_ident, + res: hir::LifetimeName::Infer, + }); + let context_path = hir::QPath::LangItem(hir::LangItem::Context, self.lower_span(span)); + let context_ty = hir::MutTy { + ty: self.arena.alloc(hir::Ty { + hir_id: self.next_id(), + kind: hir::TyKind::Path(context_path), + span: self.lower_span(span), + }), + mutbl: hir::Mutability::Mut, + }; + let input_ty = hir::Ty { hir_id: self.next_id(), - kind: hir::TyKind::Path(resume_ty), - span: unstable_span, + kind: hir::TyKind::Ref(context_lifetime, context_ty), + span: self.lower_span(span), }; // The closure/coroutine `FnDecl` takes a single (resume) argument of type `input_ty`. @@ -768,17 +778,27 @@ impl<'hir> LoweringContext<'_, 'hir> { ) -> hir::ExprKind<'hir> { let output = hir::FnRetTy::DefaultReturn(self.lower_span(span)); - // Resume argument type: `ResumeTy` - let unstable_span = self.mark_span_with_reason( - DesugaringKind::Async, - self.lower_span(span), - Some(self.allow_gen_future.clone()), - ); - let resume_ty = self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span); + // Resume argument type: `&mut Context<'_>`. + let context_lifetime_ident = Ident::with_dummy_span(kw::UnderscoreLifetime); + let context_lifetime = self.arena.alloc(hir::Lifetime { + hir_id: self.next_id(), + ident: context_lifetime_ident, + res: hir::LifetimeName::Infer, + }); + let context_path = hir::QPath::LangItem(hir::LangItem::Context, self.lower_span(span)); + let context_ty = hir::MutTy { + ty: self.arena.alloc(hir::Ty { + hir_id: self.next_id(), + kind: hir::TyKind::Path(context_path), + span: self.lower_span(span), + }), + mutbl: hir::Mutability::Mut, + }; + let input_ty = hir::Ty { hir_id: self.next_id(), - kind: hir::TyKind::Path(resume_ty), - span: unstable_span, + kind: hir::TyKind::Ref(context_lifetime, context_ty), + span: self.lower_span(span), }; // The closure/coroutine `FnDecl` takes a single (resume) argument of type `input_ty`. @@ -871,7 +891,7 @@ impl<'hir> LoweringContext<'_, 'hir> { /// mut __awaitee => loop { /// match unsafe { ::std::future::Future::poll( /// <::std::pin::Pin>::new_unchecked(&mut __awaitee), - /// ::std::future::get_context(task_context), + /// task_context, /// ) } { /// ::std::task::Poll::Ready(result) => break result, /// ::std::task::Poll::Pending => {} @@ -912,29 +932,21 @@ impl<'hir> LoweringContext<'_, 'hir> { FutureKind::AsyncIterator => Some(self.allow_for_await.clone()), }; let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features); - let gen_future_span = self.mark_span_with_reason( - DesugaringKind::Await, - full_span, - Some(self.allow_gen_future.clone()), - ); let expr_hir_id = expr.hir_id; // Note that the name of this binding must not be changed to something else because // debuggers and debugger extensions expect it to be called `__awaitee`. They use // this name to identify what is being awaited by a suspended async functions. let awaitee_ident = Ident::with_dummy_span(sym::__awaitee); - let (awaitee_pat, awaitee_pat_hid) = self.pat_ident_binding_mode( - gen_future_span, - awaitee_ident, - hir::BindingAnnotation::MUT, - ); + let (awaitee_pat, awaitee_pat_hid) = + self.pat_ident_binding_mode(full_span, awaitee_ident, hir::BindingAnnotation::MUT); let task_context_ident = Ident::with_dummy_span(sym::_task_context); // unsafe { // ::std::future::Future::poll( // ::std::pin::Pin::new_unchecked(&mut __awaitee), - // ::std::future::get_context(task_context), + // task_context, // ) // } let poll_expr = { @@ -952,21 +964,16 @@ impl<'hir> LoweringContext<'_, 'hir> { hir::LangItem::PinNewUnchecked, arena_vec![self; ref_mut_awaitee], ); - let get_context = self.expr_call_lang_item_fn_mut( - gen_future_span, - hir::LangItem::GetContext, - arena_vec![self; task_context], - ); let call = match await_kind { FutureKind::Future => self.expr_call_lang_item_fn( span, hir::LangItem::FuturePoll, - arena_vec![self; new_unchecked, get_context], + arena_vec![self; new_unchecked, task_context], ), FutureKind::AsyncIterator => self.expr_call_lang_item_fn( span, hir::LangItem::AsyncIteratorPollNext, - arena_vec![self; new_unchecked, get_context], + arena_vec![self; new_unchecked, task_context], ), }; self.arena.alloc(self.expr_unsafe(call)) @@ -977,14 +984,14 @@ impl<'hir> LoweringContext<'_, 'hir> { let loop_hir_id = self.lower_node_id(loop_node_id); let ready_arm = { let x_ident = Ident::with_dummy_span(sym::result); - let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident); - let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid); - let ready_field = self.single_pat_field(gen_future_span, x_pat); + let (x_pat, x_pat_hid) = self.pat_ident(full_span, x_ident); + let x_expr = self.expr_ident(full_span, x_ident, x_pat_hid); + let ready_field = self.single_pat_field(full_span, x_pat); let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field); let break_x = self.with_loop_scope(loop_node_id, move |this| { let expr_break = hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr)); - this.arena.alloc(this.expr(gen_future_span, expr_break)) + this.arena.alloc(this.expr(full_span, expr_break)) }); self.arm(ready_pat, break_x) }; diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs index 3f3b57ba94f98..8a6c7c31d270c 100644 --- a/compiler/rustc_hir/src/lang_items.rs +++ b/compiler/rustc_hir/src/lang_items.rs @@ -299,11 +299,6 @@ language_item_table! { AsyncGenPending, sym::AsyncGenPending, async_gen_pending, Target::AssocConst, GenericRequirement::Exact(1); AsyncGenFinished, sym::AsyncGenFinished, async_gen_finished, Target::AssocConst, GenericRequirement::Exact(1); - // FIXME(swatinem): the following lang items are used for async lowering and - // should become obsolete eventually. - ResumeTy, sym::ResumeTy, resume_ty, Target::Struct, GenericRequirement::None; - GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None; - Context, sym::Context, context, Target::Struct, GenericRequirement::None; FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; diff --git a/compiler/rustc_mir_transform/src/coroutine.rs b/compiler/rustc_mir_transform/src/coroutine.rs index 05d8d842b5813..f881504c49dde 100644 --- a/compiler/rustc_mir_transform/src/coroutine.rs +++ b/compiler/rustc_mir_transform/src/coroutine.rs @@ -616,104 +616,6 @@ fn replace_local<'tcx>( new_local } -/// Transforms the `body` of the coroutine applying the following transforms: -/// -/// - Eliminates all the `get_context` calls that async lowering created. -/// - Replace all `Local` `ResumeTy` types with `&mut Context<'_>` (`context_mut_ref`). -/// -/// The `Local`s that have their types replaced are: -/// - The `resume` argument itself. -/// - The argument to `get_context`. -/// - The yielded value of a `yield`. -/// -/// The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the -/// `get_context` function is being used to convert that back to a `&mut Context<'_>`. -/// -/// Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection, -/// but rather directly use `&mut Context<'_>`, however that would currently -/// lead to higher-kinded lifetime errors. -/// See . -/// -/// The async lowering step and the type / lifetime inference / checking are -/// still using the `ResumeTy` indirection for the time being, and that indirection -/// is removed here. After this transform, the coroutine body only knows about `&mut Context<'_>`. -fn transform_async_context<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let context_mut_ref = Ty::new_task_context(tcx); - - // replace the type of the `resume` argument - replace_resume_ty_local(tcx, body, Local::new(2), context_mut_ref); - - let get_context_def_id = tcx.require_lang_item(LangItem::GetContext, None); - - for bb in START_BLOCK..body.basic_blocks.next_index() { - let bb_data = &body[bb]; - if bb_data.is_cleanup { - continue; - } - - match &bb_data.terminator().kind { - TerminatorKind::Call { func, .. } => { - let func_ty = func.ty(body, tcx); - if let ty::FnDef(def_id, _) = *func_ty.kind() { - if def_id == get_context_def_id { - let local = eliminate_get_context_call(&mut body[bb]); - replace_resume_ty_local(tcx, body, local, context_mut_ref); - } - } else { - continue; - } - } - TerminatorKind::Yield { resume_arg, .. } => { - replace_resume_ty_local(tcx, body, resume_arg.local, context_mut_ref); - } - _ => {} - } - } -} - -fn eliminate_get_context_call<'tcx>(bb_data: &mut BasicBlockData<'tcx>) -> Local { - let terminator = bb_data.terminator.take().unwrap(); - if let TerminatorKind::Call { mut args, destination, target, .. } = terminator.kind { - let arg = args.pop().unwrap(); - let local = arg.place().unwrap().local; - - let arg = Rvalue::Use(arg); - let assign = Statement { - source_info: terminator.source_info, - kind: StatementKind::Assign(Box::new((destination, arg))), - }; - bb_data.statements.push(assign); - bb_data.terminator = Some(Terminator { - source_info: terminator.source_info, - kind: TerminatorKind::Goto { target: target.unwrap() }, - }); - local - } else { - bug!(); - } -} - -#[cfg_attr(not(debug_assertions), allow(unused))] -fn replace_resume_ty_local<'tcx>( - tcx: TyCtxt<'tcx>, - body: &mut Body<'tcx>, - local: Local, - context_mut_ref: Ty<'tcx>, -) { - let local_ty = std::mem::replace(&mut body.local_decls[local].ty, context_mut_ref); - // We have to replace the `ResumeTy` that is used for type and borrow checking - // with `&mut Context<'_>` in MIR. - #[cfg(debug_assertions)] - { - if let ty::Adt(resume_ty_adt, _) = local_ty.kind() { - let expected_adt = tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None)); - assert_eq!(*resume_ty_adt, expected_adt); - } else { - panic!("expected `ResumeTy`, found `{:?}`", local_ty); - }; - } -} - /// Transforms the `body` of the coroutine applying the following transform: /// /// - Remove the `resume` argument. @@ -721,7 +623,7 @@ fn replace_resume_ty_local<'tcx>( /// Ideally the async lowering would not add the `resume` argument. /// /// The async lowering step and the type / lifetime inference / checking are -/// still using the `resume` argument for the time being. After this transform, +/// still using the `resume` argument for the time being. After this transform /// the coroutine body doesn't have the `resume` argument. fn transform_gen_context<'tcx>(_tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { // This leaves the local representing the `resume` argument in place, @@ -1613,14 +1515,6 @@ impl<'tcx> MirPass<'tcx> for StateTransform { } }; - let is_async_kind = matches!( - body.coroutine_kind(), - Some(CoroutineKind::Desugared(CoroutineDesugaring::Async, _)) - ); - let is_async_gen_kind = matches!( - body.coroutine_kind(), - Some(CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _)) - ); let is_gen_kind = matches!( body.coroutine_kind(), Some(CoroutineKind::Desugared(CoroutineDesugaring::Gen, _)) @@ -1657,22 +1551,13 @@ impl<'tcx> MirPass<'tcx> for StateTransform { // RETURN_PLACE then is a fresh unused local with type ret_ty. let old_ret_local = replace_local(RETURN_PLACE, new_ret_ty, body, tcx); - // Replace all occurrences of `ResumeTy` with `&mut Context<'_>` within async bodies. - if is_async_kind || is_async_gen_kind { - transform_async_context(tcx, body); - } - // We also replace the resume argument and insert an `Assign`. // This is needed because the resume argument `_2` might be live across a `yield`, in which // case there is no `Assign` to it that the transform can turn into a store to the coroutine // state. After the yield the slot in the coroutine state would then be uninitialized. let resume_local = Local::new(2); - let resume_ty = if is_async_kind { - Ty::new_task_context(tcx) - } else { - body.local_decls[resume_local].ty - }; - let old_resume_local = replace_local(resume_local, resume_ty, body, tcx); + let old_resume_local = + replace_local(resume_local, body.local_decls[resume_local].ty, body, tcx); // When first entering the coroutine, move the resume argument into its old local // (which is now a generator interior). diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 0b44071496ea8..3fee213faa426 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -291,7 +291,6 @@ symbols! { Relaxed, Release, Result, - ResumeTy, Return, Right, Rust, @@ -833,7 +832,6 @@ symbols! { generic_const_exprs, generic_const_items, generic_param_attrs, - get_context, global_allocator, global_asm, globs, diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs index 4756a45a44781..cdabe19930e80 100644 --- a/compiler/rustc_ty_utils/src/abi.rs +++ b/compiler/rustc_ty_utils/src/abi.rs @@ -140,21 +140,7 @@ fn fn_sig_for_fn_abi<'tcx>( let poll_args = tcx.mk_args(&[sig.return_ty.into()]); let ret_ty = Ty::new_adt(tcx, poll_adt_ref, poll_args); - // We have to replace the `ResumeTy` that is used for type and borrow checking - // with `&mut Context<'_>` which is used in codegen. - #[cfg(debug_assertions)] - { - if let ty::Adt(resume_ty_adt, _) = sig.resume_ty.kind() { - let expected_adt = - tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None)); - assert_eq!(*resume_ty_adt, expected_adt); - } else { - panic!("expected `ResumeTy`, found `{:?}`", sig.resume_ty); - }; - } - let context_mut_ref = Ty::new_task_context(tcx); - - (Some(context_mut_ref), ret_ty) + (Some(sig.resume_ty), ret_ty) } hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _) => { // The signature should be `Iterator::next(_) -> Option` @@ -176,21 +162,7 @@ fn fn_sig_for_fn_abi<'tcx>( // Yield type is already `Poll>` let ret_ty = sig.yield_ty; - // We have to replace the `ResumeTy` that is used for type and borrow checking - // with `&mut Context<'_>` which is used in codegen. - #[cfg(debug_assertions)] - { - if let ty::Adt(resume_ty_adt, _) = sig.resume_ty.kind() { - let expected_adt = - tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None)); - assert_eq!(*resume_ty_adt, expected_adt); - } else { - panic!("expected `ResumeTy`, found `{:?}`", sig.resume_ty); - }; - } - let context_mut_ref = Ty::new_task_context(tcx); - - (Some(context_mut_ref), ret_ty) + (Some(sig.resume_ty), ret_ty) } hir::CoroutineKind::Coroutine(_) => { // The signature should be `Coroutine::resume(_, Resume) -> CoroutineState` diff --git a/library/core/src/future/mod.rs b/library/core/src/future/mod.rs index 0f77a2d83433f..876915eb50b41 100644 --- a/library/core/src/future/mod.rs +++ b/library/core/src/future/mod.rs @@ -44,7 +44,7 @@ pub use poll_fn::{poll_fn, PollFn}; /// non-Send/Sync as well, and we don't want that. /// /// It also simplifies the HIR lowering of `.await`. -#[lang = "ResumeTy"] +#[cfg_attr(bootstrap, lang = "ResumeTy")] #[doc(hidden)] #[unstable(feature = "gen_future", issue = "50547")] #[derive(Debug, Copy, Clone)] @@ -56,7 +56,7 @@ unsafe impl Send for ResumeTy {} #[unstable(feature = "gen_future", issue = "50547")] unsafe impl Sync for ResumeTy {} -#[lang = "get_context"] +#[cfg_attr(bootstrap, lang = "get_context")] #[doc(hidden)] #[unstable(feature = "gen_future", issue = "50547")] #[must_use] diff --git a/tests/ui/async-await/issue-69446-fnmut-capture.stderr b/tests/ui/async-await/issue-69446-fnmut-capture.stderr index 0366c2f44c0e7..27cea6155f743 100644 --- a/tests/ui/async-await/issue-69446-fnmut-capture.stderr +++ b/tests/ui/async-await/issue-69446-fnmut-capture.stderr @@ -14,6 +14,9 @@ LL | | }); | = note: `FnMut` closures only have access to their captured variables while they are executing... = note: ...therefore, they cannot allow references to captured variables to escape + = note: requirement occurs because of a mutable reference to `Context<'_>` + = note: mutable references are invariant over their type parameter + = help: see for more information about variance error: aborting due to 1 previous error diff --git a/tests/ui/async-await/unreachable-lint.rs b/tests/ui/async-await/unreachable-lint.rs index ca18cfde4f2f5..decb74070b8ec 100644 --- a/tests/ui/async-await/unreachable-lint.rs +++ b/tests/ui/async-await/unreachable-lint.rs @@ -1,9 +1,9 @@ -// check-pass // edition:2018 #![deny(unreachable_code)] async fn foo() { endless().await; + //~^ ERROR unreachable expression } async fn endless() -> ! { diff --git a/tests/ui/async-await/unreachable-lint.stderr b/tests/ui/async-await/unreachable-lint.stderr new file mode 100644 index 0000000000000..0d4b3a279b4cf --- /dev/null +++ b/tests/ui/async-await/unreachable-lint.stderr @@ -0,0 +1,17 @@ +error: unreachable expression + --> $DIR/unreachable-lint.rs:5:5 + | +LL | endless().await; + | ^^^^^^^^^^^^^^^ + | | + | unreachable expression + | any code following this expression is unreachable + | +note: the lint level is defined here + --> $DIR/unreachable-lint.rs:2:9 + | +LL | #![deny(unreachable_code)] + | ^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error + diff --git a/tests/ui/regions/closure-in-projection-issue-97405.rs b/tests/ui/regions/closure-in-projection-issue-97405.rs index 5489533972e73..3b4413724e2d1 100644 --- a/tests/ui/regions/closure-in-projection-issue-97405.rs +++ b/tests/ui/regions/closure-in-projection-issue-97405.rs @@ -22,11 +22,11 @@ fn good_generic_fn() { // This should fail because `T` ends up in the upvars of the closure. fn bad_generic_fn(t: T) { assert_static(opaque(async move { t; }).next()); - //~^ ERROR the associated type `::Item` may not live long enough + //~^ ERROR the parameter type `T` may not live long enough assert_static(opaque(move || { t; }).next()); //~^ ERROR the associated type `::Item` may not live long enough assert_static(opaque(opaque(async move { t; }).next()).next()); - //~^ ERROR the associated type `::Item` may not live long enough + //~^ ERROR the parameter type `T` may not live long enough } fn main() {} diff --git a/tests/ui/regions/closure-in-projection-issue-97405.stderr b/tests/ui/regions/closure-in-projection-issue-97405.stderr index 7070dfef138ac..29e24bf2d4c05 100644 --- a/tests/ui/regions/closure-in-projection-issue-97405.stderr +++ b/tests/ui/regions/closure-in-projection-issue-97405.stderr @@ -1,13 +1,16 @@ -error[E0310]: the associated type `::Item` may not live long enough +error[E0310]: the parameter type `T` may not live long enough --> $DIR/closure-in-projection-issue-97405.rs:24:5 | LL | assert_static(opaque(async move { t; }).next()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | - | the associated type `::Item` must be valid for the static lifetime... - | ...so that the type `::Item` will meet its required lifetime bounds + | the parameter type `T` must be valid for the static lifetime... + | ...so that the type `T` will meet its required lifetime bounds | - = help: consider adding an explicit lifetime bound `::Item: 'static`... +help: consider adding an explicit lifetime bound + | +LL | fn bad_generic_fn(t: T) { + | +++++++++ error[E0310]: the associated type `::Item` may not live long enough --> $DIR/closure-in-projection-issue-97405.rs:26:5 @@ -20,16 +23,19 @@ LL | assert_static(opaque(move || { t; }).next()); | = help: consider adding an explicit lifetime bound `::Item: 'static`... -error[E0310]: the associated type `::Item` may not live long enough +error[E0310]: the parameter type `T` may not live long enough --> $DIR/closure-in-projection-issue-97405.rs:28:5 | LL | assert_static(opaque(opaque(async move { t; }).next()).next()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | | - | the associated type `::Item` must be valid for the static lifetime... - | ...so that the type `::Item` will meet its required lifetime bounds + | the parameter type `T` must be valid for the static lifetime... + | ...so that the type `T` will meet its required lifetime bounds | - = help: consider adding an explicit lifetime bound `::Item: 'static`... +help: consider adding an explicit lifetime bound + | +LL | fn bad_generic_fn(t: T) { + | +++++++++ error: aborting due to 3 previous errors