new_local
}
+/// Transforms the `body` of the generator 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 <https://github.com/rust-lang/rust/issues/105501>.
+///
+/// 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 generator body only knows about `&mut Context<'_>`.
+fn transform_async_context<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+ let context_mut_ref = tcx.mk_task_context();
+
+ // 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 BasicBlock::new(0)..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);
+ };
+ }
+}
+
struct LivenessInfo {
/// Which locals are live across any suspension point.
saved_locals: GeneratorSavedLocals,
}
};
- let is_async_kind = body.generator_kind().unwrap() != GeneratorKind::Gen;
+ let is_async_kind = matches!(body.generator_kind(), Some(GeneratorKind::Async(_)));
let (state_adt_ref, state_substs) = if is_async_kind {
// Compute Poll<return_ty>
- let state_did = tcx.require_lang_item(LangItem::Poll, None);
- let state_adt_ref = tcx.adt_def(state_did);
- let state_substs = tcx.intern_substs(&[body.return_ty().into()]);
- (state_adt_ref, state_substs)
+ let poll_did = tcx.require_lang_item(LangItem::Poll, None);
+ let poll_adt_ref = tcx.adt_def(poll_did);
+ let poll_substs = tcx.intern_substs(&[body.return_ty().into()]);
+ (poll_adt_ref, poll_substs)
} else {
// Compute GeneratorState<yield_ty, return_ty>
let state_did = tcx.require_lang_item(LangItem::GeneratorState, None);
// RETURN_PLACE then is a fresh unused local with type ret_ty.
let new_ret_local = replace_local(RETURN_PLACE, ret_ty, body, tcx);
+ // Replace all occurrences of `ResumeTy` with `&mut Context<'_>` within async bodies.
+ if is_async_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 generator
// state. After the yield the slot in the generator state would then be uninitialized.
let resume_local = Local::new(2);
- let new_resume_local =
- replace_local(resume_local, body.local_decls[resume_local].ty, body, tcx);
+ let resume_ty =
+ if is_async_kind { tcx.mk_task_context() } else { body.local_decls[resume_local].ty };
+ let new_resume_local = replace_local(resume_local, resume_ty, body, tcx);
// When first entering the generator, move the resume argument into its new local.
let source_info = SourceInfo::outermost(body.span);
--- /dev/null
+// MIR for `b::{closure#0}` 0 generator_resume
+/* generator_layout = GeneratorLayout {
+ field_tys: {
+ _0: impl std::future::Future<Output = ()>,
+ _1: impl std::future::Future<Output = ()>,
+ },
+ variant_fields: {
+ Unresumed(0): [],
+ Returned (1): [],
+ Panicked (2): [],
+ Suspend0 (3): [_0],
+ Suspend1 (4): [_1],
+ },
+ storage_conflicts: BitMatrix(2x2) {
+ (_0, _0),
+ (_1, _1),
+ },
+} */
+
+fn b::{closure#0}(_1: Pin<&mut [async fn body@$DIR/async_await.rs:14:18: 17:2]>, _2: &mut Context<'_>) -> Poll<()> {
+ debug _task_context => _38; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ let mut _0: std::task::Poll<()>; // return place in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ let _3: (); // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+ let mut _4: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _5: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:8
+ let mut _6: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _7: (); // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ let _8: (); // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _9: std::task::Poll<()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _10: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _11: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _12: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _13: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+ let mut _14: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+ let mut _15: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _16: isize; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _18: !; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+ let mut _19: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _20: (); // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ let mut _21: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _22: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:8
+ let mut _23: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let _24: (); // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _25: std::task::Poll<()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _26: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _27: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _28: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _29: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+ let mut _30: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+ let mut _31: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _32: isize; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _34: !; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+ let mut _35: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _36: (); // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ let mut _37: (); // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ let mut _38: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ let mut _39: u32; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ scope 1 {
+ debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // in scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ let _17: (); // in scope 1 at $DIR/async_await.rs:+1:5: +1:14
+ scope 2 {
+ }
+ scope 3 {
+ debug result => _17; // in scope 3 at $DIR/async_await.rs:+1:5: +1:14
+ }
+ }
+ scope 4 {
+ debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // in scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ let _33: (); // in scope 4 at $DIR/async_await.rs:+2:5: +2:14
+ scope 5 {
+ }
+ scope 6 {
+ debug result => _33; // in scope 6 at $DIR/async_await.rs:+2:5: +2:14
+ }
+ }
+
+ bb0: {
+ _39 = discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ switchInt(move _39) -> [0: bb1, 1: bb29, 3: bb27, 4: bb28, otherwise: bb30]; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ }
+
+ bb1: {
+ _38 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_3); // scope 0 at $DIR/async_await.rs:+1:5: +1:14
+ StorageLive(_4); // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_5); // scope 0 at $DIR/async_await.rs:+1:5: +1:8
+ _5 = a() -> bb2; // scope 0 at $DIR/async_await.rs:+1:5: +1:8
+ // mir::Constant
+ // + span: $DIR/async_await.rs:15:5: 15:6
+ // + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
+ }
+
+ bb2: {
+ _4 = <impl Future<Output = ()> as IntoFuture>::into_future(move _5) -> bb3; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:15:8: 15:14
+ // + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
+ }
+
+ bb3: {
+ StorageDead(_5); // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+ nop; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>) = move _4; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+ goto -> bb4; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ }
+
+ bb4: {
+ StorageLive(_8); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_9); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_10); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_11); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_12); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ _12 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ _11 = &mut (*_12); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ _10 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _11) -> bb5; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:15:8: 15:14
+ // + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
+ }
+
+ bb5: {
+ StorageDead(_11); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+ StorageLive(_13); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+ StorageLive(_14); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+ StorageLive(_15); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ _15 = _38; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ _14 = move _15; // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+ goto -> bb6; // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+ }
+
+ bb6: {
+ _13 = &mut (*_14); // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+ StorageDead(_15); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+ _9 = <impl Future<Output = ()> as Future>::poll(move _10, move _13) -> bb7; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:15:8: 15:14
+ // + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
+ }
+
+ bb7: {
+ StorageDead(_13); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_10); // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+ _16 = discriminant(_9); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ switchInt(move _16) -> [0: bb10, 1: bb8, otherwise: bb9]; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ }
+
+ bb8: {
+ _8 = const (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ StorageDead(_14); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_12); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_9); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_8); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageLive(_19); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ StorageLive(_20); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ _20 = (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ Deinit(_0); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ discriminant(_0) = 1; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 3; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ return; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ }
+
+ bb9: {
+ unreachable; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ }
+
+ bb10: {
+ StorageLive(_17); // scope 1 at $DIR/async_await.rs:+1:5: +1:14
+ _17 = ((_9 as Ready).0: ()); // scope 1 at $DIR/async_await.rs:+1:5: +1:14
+ _3 = _17; // scope 3 at $DIR/async_await.rs:+1:5: +1:14
+ StorageDead(_17); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_14); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_12); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_9); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ StorageDead(_8); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ goto -> bb12; // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+ }
+
+ bb11: {
+ StorageDead(_20); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ _38 = move _19; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ StorageDead(_19); // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+ _7 = const (); // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ goto -> bb4; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+ }
+
+ bb12: {
+ nop; // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+ goto -> bb13; // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+ }
+
+ bb13: {
+ StorageDead(_4); // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+ StorageDead(_3); // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+ StorageLive(_21); // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_22); // scope 0 at $DIR/async_await.rs:+2:5: +2:8
+ _22 = a() -> bb14; // scope 0 at $DIR/async_await.rs:+2:5: +2:8
+ // mir::Constant
+ // + span: $DIR/async_await.rs:16:5: 16:6
+ // + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
+ }
+
+ bb14: {
+ _21 = <impl Future<Output = ()> as IntoFuture>::into_future(move _22) -> bb15; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:16:8: 16:14
+ // + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
+ }
+
+ bb15: {
+ StorageDead(_22); // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+ nop; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>) = move _21; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+ goto -> bb16; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ }
+
+ bb16: {
+ StorageLive(_24); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_25); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_26); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_27); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_28); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ _28 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ _27 = &mut (*_28); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ _26 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _27) -> bb17; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:16:8: 16:14
+ // + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
+ }
+
+ bb17: {
+ StorageDead(_27); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+ StorageLive(_29); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+ StorageLive(_30); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+ StorageLive(_31); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ _31 = _38; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ _30 = move _31; // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+ goto -> bb18; // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+ }
+
+ bb18: {
+ _29 = &mut (*_30); // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+ StorageDead(_31); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+ _25 = <impl Future<Output = ()> as Future>::poll(move _26, move _29) -> bb19; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+ // mir::Constant
+ // + span: $DIR/async_await.rs:16:8: 16:14
+ // + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
+ }
+
+ bb19: {
+ StorageDead(_29); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_26); // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+ _32 = discriminant(_25); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ switchInt(move _32) -> [0: bb22, 1: bb20, otherwise: bb21]; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ }
+
+ bb20: {
+ _24 = const (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ StorageDead(_30); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_28); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_25); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_24); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageLive(_35); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ StorageLive(_36); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ _36 = (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ Deinit(_0); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ discriminant(_0) = 1; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 4; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ return; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ }
+
+ bb21: {
+ unreachable; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ }
+
+ bb22: {
+ StorageLive(_33); // scope 4 at $DIR/async_await.rs:+2:5: +2:14
+ _33 = ((_25 as Ready).0: ()); // scope 4 at $DIR/async_await.rs:+2:5: +2:14
+ _37 = _33; // scope 6 at $DIR/async_await.rs:+2:5: +2:14
+ StorageDead(_33); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_30); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_28); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_25); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ StorageDead(_24); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ goto -> bb24; // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+ }
+
+ bb23: {
+ StorageDead(_36); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ _38 = move _35; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ StorageDead(_35); // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+ _7 = const (); // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ goto -> bb16; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+ }
+
+ bb24: {
+ nop; // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+ goto -> bb25; // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+ }
+
+ bb25: {
+ StorageDead(_21); // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+ goto -> bb26; // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+ }
+
+ bb26: {
+ Deinit(_0); // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+ ((_0 as Ready).0: ()) = move _37; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+ discriminant(_0) = 0; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+ discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 1; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+ return; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+ }
+
+ bb27: {
+ StorageLive(_3); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_4); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_19); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_20); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ _19 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ goto -> bb11; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ }
+
+ bb28: {
+ StorageLive(_21); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_35); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ StorageLive(_36); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ _35 = move _2; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ goto -> bb23; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ }
+
+ bb29: {
+ assert(const false, "`async fn` resumed after completion") -> bb29; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ }
+
+ bb30: {
+ unreachable; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+ }
+}