End locals' live range before suspending coroutine

compiler/rustc_mir_transform/src/coroutine.rs

@@ -527,12 +527,26 @@ impl<'tcx> MutVisitor<'tcx> for TransformVisitor<'tcx> {
                         resume_arg
                     };
 
+                let storage_liveness: GrowableBitSet<Local> =
+                    self.storage_liveness[block].clone().unwrap().into();
+
+                for i in 0..self.always_live_locals.domain_size() {
+                    let l = Local::new(i);
+                    let needs_storage_dead = storage_liveness.contains(l)
+                        && !self.remap.contains_key(&l)
+                        && !self.always_live_locals.contains(l);
+                    if needs_storage_dead {
+                        data.statements
+                            .push(Statement { source_info, kind: StatementKind::StorageDead(l) });
+                    }
+                }
+
                 self.suspension_points.push(SuspensionPoint {
                     state,
                     resume,
                     resume_arg,
                     drop,
-                    storage_liveness: self.storage_liveness[block].clone().unwrap().into(),
+                    storage_liveness,
                 });
 
                 VariantIdx::new(state)
@@ -1496,13 +1510,6 @@ fn create_cases<'tcx>(
 
                 // Create StorageLive instructions for locals with live storage
                 for i in 0..(body.local_decls.len()) {
-                    if i == 2 {
-                        // The resume argument is live on function entry. Don't insert a
-                        // `StorageLive`, or the following `Assign` will read from uninitialized
-                        // memory.
-                        continue;
-                    }
-
                     let l = Local::new(i);
                     let needs_storage_live = point.storage_liveness.contains(l)
                         && !transform.remap.contains_key(&l)

tests/mir-opt/building/async_await.b-{closure#0}.coroutine_resume.0.mir

@@ -178,6 +178,10 @@ fn b::{closure#0}(_1: Pin<&mut {async fn body@$DIR/async_await.rs:15:18: 18:2}>,
         StorageLive(_20);
         _20 = ();
         _0 = Poll::<()>::Pending;
+        StorageDead(_3);
+        StorageDead(_4);
+        StorageDead(_19);
+        StorageDead(_20);
         discriminant((*(_1.0: &mut {async fn body@$DIR/async_await.rs:15:18: 18:2}))) = 3;
         return;
     }
@@ -276,6 +280,9 @@ fn b::{closure#0}(_1: Pin<&mut {async fn body@$DIR/async_await.rs:15:18: 18:2}>,
         StorageLive(_36);
         _36 = ();
         _0 = Poll::<()>::Pending;
+        StorageDead(_21);
+        StorageDead(_35);
+        StorageDead(_36);
         discriminant((*(_1.0: &mut {async fn body@$DIR/async_await.rs:15:18: 18:2}))) = 4;
         return;
     }

tests/mir-opt/coroutine_tiny.main-{closure#0}.coroutine_resume.0.mir

@@ -55,6 +55,9 @@ fn main::{closure#0}(_1: Pin<&mut {coroutine@$DIR/coroutine_tiny.rs:20:16: 20:24
         StorageLive(_7);
         _7 = ();
         _0 = CoroutineState::<(), ()>::Yielded(move _7);
+        StorageDead(_4);
+        StorageDead(_6);
+        StorageDead(_7);
         discriminant((*(_1.0: &mut {coroutine@$DIR/coroutine_tiny.rs:20:16: 20:24}))) = 3;
         return;
     }

tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff

@@ -89,6 +89,7 @@
 + 
 +     bb6: {
 +         _1 = CoroutineState::<i32, bool>::Yielded(move _8);
++         StorageDead(_8);
 +         discriminant((*_6)) = 3;
 +         goto -> bb2;
 +     }

tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff

@@ -103,6 +103,7 @@
 + 
 +     bb8: {
 +         _1 = CoroutineState::<i32, bool>::Yielded(move _8);
++         StorageDead(_8);
 +         discriminant((*_6)) = 3;
 +         goto -> bb4;
 +     }