destroy temp at the end and avoid ICE

4 files changed, 14 insertions, 11 deletions

diff --git a/compiler/rustc_mir_transform/src/deref_separator.rs b/compiler/rustc_mir_transform/src/deref_separator.rs
index c6efe79caaf..17e58a3bb89 100644
--- a/compiler/rustc_mir_transform/src/deref_separator.rs
+++ b/compiler/rustc_mir_transform/src/deref_separator.rs
@@ -8,11 +8,15 @@ pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let mut patch = MirPatch::new(body);
     let (basic_blocks, local_decl) = body.basic_blocks_and_local_decls_mut();
     for (block, data) in basic_blocks.iter_enumerated_mut() {
+        let statement_len = data.statements.len();
         for (i, stmt) in data.statements.iter_mut().enumerate() {
             match stmt.kind {
                 StatementKind::Assign(box (og_place, Rvalue::Ref(region, borrow_knd, place))) => {
                     for (idx, (p_ref, p_elem)) in place.iter_projections().enumerate() {
-                        if p_elem == ProjectionElem::Deref && !p_ref.projection.is_empty() {
+                        if p_elem == ProjectionElem::Deref
+                            && !p_ref.projection.is_empty()
+                            && region.is_erased()
+                        {
                             // The type that we are derefing
                             let ty = p_ref.ty(local_decl, tcx).ty;
                             let temp = patch.new_temp(ty, stmt.source_info.span);
@@ -36,12 +40,6 @@ pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
                             // and copying derefed values which we need to create new statement
                             let temp_place =
                                 Place::from(temp).project_deeper(&place.projection[idx..], tcx);
-                            patch.add_assign(
-                                loc,
-                                og_place,
-                                Rvalue::Ref(region, borrow_knd, temp_place),
-                            );
-
                             let new_stmt = Statement {
                                 source_info: stmt.source_info,
                                 kind: StatementKind::Assign(Box::new((
@@ -49,8 +47,13 @@ pub fn deref_finder<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
                                     Rvalue::Ref(region, borrow_knd, temp_place),
                                 ))),
                             };
+
                             // Replace current statement with newly created one
                             *stmt = new_stmt;
+
+                            // Since our job with the temp is done it should be gone
+                            let loc = Location { block: block, statement_index: statement_len };
+                            patch.add_statement(loc, StatementKind::StorageDead(temp));
                         }
                     }
                 }
diff --git a/src/test/mir-opt/derefer_test.main.Derefer.diff b/src/test/mir-opt/derefer_test.main.Derefer.diff
index 018049519cf..b9b2f70518a 100644
--- a/src/test/mir-opt/derefer_test.main.Derefer.diff
+++ b/src/test/mir-opt/derefer_test.main.Derefer.diff
@@ -38,18 +38,18 @@
 +         StorageLive(_6);                 // scope 2 at $DIR/derefer_test.rs:5:13: 5:26
 +         _6 = move (_2.1: &mut (i32, i32)); // scope 2 at $DIR/derefer_test.rs:5:13: 5:26
 +         _4 = &mut ((*_6).0: i32);        // scope 2 at $DIR/derefer_test.rs:5:13: 5:26
-+         _4 = &mut ((*_6).0: i32);        // scope 2 at $DIR/derefer_test.rs:5:13: 5:26
           StorageLive(_5);                 // scope 3 at $DIR/derefer_test.rs:6:9: 6:10
 -         _5 = &mut ((*(_2.1: &mut (i32, i32))).1: i32); // scope 3 at $DIR/derefer_test.rs:6:13: 6:26
 +         StorageLive(_7);                 // scope 3 at $DIR/derefer_test.rs:6:13: 6:26
 +         _7 = move (_2.1: &mut (i32, i32)); // scope 3 at $DIR/derefer_test.rs:6:13: 6:26
 +         _5 = &mut ((*_7).1: i32);        // scope 3 at $DIR/derefer_test.rs:6:13: 6:26
-+         _5 = &mut ((*_7).1: i32);        // scope 3 at $DIR/derefer_test.rs:6:13: 6:26
           _0 = const ();                   // scope 0 at $DIR/derefer_test.rs:2:11: 7:2
           StorageDead(_5);                 // scope 3 at $DIR/derefer_test.rs:7:1: 7:2
           StorageDead(_4);                 // scope 2 at $DIR/derefer_test.rs:7:1: 7:2
           StorageDead(_2);                 // scope 1 at $DIR/derefer_test.rs:7:1: 7:2
           StorageDead(_1);                 // scope 0 at $DIR/derefer_test.rs:7:1: 7:2
++         StorageDead(_6);                 // scope 0 at $DIR/derefer_test.rs:7:2: 7:2
++         StorageDead(_7);                 // scope 0 at $DIR/derefer_test.rs:7:2: 7:2
           return;                          // scope 0 at $DIR/derefer_test.rs:7:2: 7:2
 +     }
 + 
diff --git a/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.b.Inline.after.mir b/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.b.Inline.after.mir
index 76a83972c65..1312f1a1556 100644
--- a/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.b.Inline.after.mir
+++ b/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.b.Inline.after.mir
@@ -23,11 +23,11 @@ fn b(_1: &mut Box<T>) -> &mut T {
         StorageLive(_7);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _7 = move (*_4);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _6 = &mut (*_7);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
-        _6 = &mut (*_7);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _5 = &mut (*_6);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _3 = &mut (*_5);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         StorageDead(_6);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         StorageDead(_5);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
+        StorageDead(_7);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _2 = &mut (*_3);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:15
         StorageDead(_4);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:14: 8:15
         _0 = &mut (*_2);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:8:5: 8:15
diff --git a/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.d.Inline.after.mir b/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.d.Inline.after.mir
index 433458ed924..d079ba59ffc 100644
--- a/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.d.Inline.after.mir
+++ b/src/test/mir-opt/inline/issue_58867_inline_as_ref_as_mut.d.Inline.after.mir
@@ -17,7 +17,7 @@ fn d(_1: &Box<T>) -> &T {
         StorageLive(_4);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _4 = move (*_3);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _2 = &(*_4);                     // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
-        _2 = &(*_4);                     // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
+        StorageDead(_4);                 // scope 1 at $SRC_DIR/alloc/src/boxed.rs:LL:COL
         _0 = &(*_2);                     // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:18:5: 18:15
         StorageDead(_3);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:18:14: 18:15
         StorageDead(_2);                 // scope 0 at $DIR/issue-58867-inline-as-ref-as-mut.rs:19:1: 19:2