Desugars drop and replace at MIR build

This commit desugars the drop and replace deriving from an
assignment at MIR build, avoiding the construction of the
DropAndReplace terminator (which will be removed in a followign PR)

In order to retain the same error messages for replaces a new
DesugaringKind::Replace variant is introduced.

20 files changed, 268 insertions, 152 deletions

diff --git a/compiler/rustc_borrowck/src/diagnostics/mod.rs b/compiler/rustc_borrowck/src/diagnostics/mod.rs
index a99fd594a07..a1817f85483 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mod.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mod.rs
@@ -925,7 +925,20 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
             return OtherUse(use_span);
         }
 
-        for stmt in &self.body[location.block].statements[location.statement_index + 1..] {
+        // drop and replace might have moved the assignment to the next block
+        let maybe_additional_statement =
+            if let TerminatorKind::Drop { target: drop_target, .. } =
+                self.body[location.block].terminator().kind
+            {
+                self.body[drop_target].statements.first()
+            } else {
+                None
+            };
+
+        let statements =
+            self.body[location.block].statements[location.statement_index + 1..].iter();
+
+        for stmt in statements.chain(maybe_additional_statement) {
             if let StatementKind::Assign(box (_, Rvalue::Aggregate(kind, places))) = &stmt.kind {
                 let (&def_id, is_generator) = match kind {
                     box AggregateKind::Closure(def_id, _) => (def_id, false),
diff --git a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
index 328ac880dd4..eded913ae96 100644
--- a/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
@@ -828,7 +828,13 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             let Some(hir::Node::Item(item)) = node else { return; };
             let hir::ItemKind::Fn(.., body_id) = item.kind else { return; };
             let body = self.infcx.tcx.hir().body(body_id);
-            let mut v = V { assign_span: span, err, ty, suggested: false };
+            let mut assign_span = span;
+            // Drop desugaring is done at MIR build so it's not in the HIR
+            if let Some(DesugaringKind::Replace) = span.desugaring_kind() {
+                assign_span.remove_mark();
+            }
+
+            let mut v = V { assign_span, err, ty, suggested: false };
             v.visit_body(body);
             if !v.suggested {
                 err.help(&format!(
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 0f591460e9d..11a746ffb0a 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -40,7 +40,7 @@ use rustc_middle::mir::{InlineAsmOperand, Terminator, TerminatorKind};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, CapturedPlace, ParamEnv, RegionVid, TyCtxt};
 use rustc_session::lint::builtin::UNUSED_MUT;
-use rustc_span::{Span, Symbol};
+use rustc_span::{DesugaringKind, Span, Symbol};
 
 use either::Either;
 use smallvec::SmallVec;
@@ -1184,13 +1184,22 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                                 this.report_conflicting_borrow(location, place_span, bk, borrow);
                             this.buffer_error(err);
                         }
-                        WriteKind::StorageDeadOrDrop => this
-                            .report_borrowed_value_does_not_live_long_enough(
-                                location,
-                                borrow,
-                                place_span,
-                                Some(kind),
-                            ),
+                        WriteKind::StorageDeadOrDrop => {
+                            if let Some(DesugaringKind::Replace) = place_span.1.desugaring_kind() {
+                                // If this is a drop triggered by a reassignment, it's more user friendly
+                                // to report a problem with the explicit assignment than the implicit drop.
+                                this.report_illegal_mutation_of_borrowed(
+                                    location, place_span, borrow,
+                                )
+                            } else {
+                                this.report_borrowed_value_does_not_live_long_enough(
+                                    location,
+                                    borrow,
+                                    place_span,
+                                    Some(kind),
+                                )
+                            }
+                        }
                         WriteKind::Mutate => {
                             this.report_illegal_mutation_of_borrowed(location, place_span, borrow)
                         }
diff --git a/compiler/rustc_mir_build/src/build/expr/stmt.rs b/compiler/rustc_mir_build/src/build/expr/stmt.rs
index 78083685193..ea5aeb67d85 100644
--- a/compiler/rustc_mir_build/src/build/expr/stmt.rs
+++ b/compiler/rustc_mir_build/src/build/expr/stmt.rs
@@ -40,7 +40,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // Generate better code for things that don't need to be
                 // dropped.
                 if lhs.ty.needs_drop(this.tcx, this.param_env) {
-                    let rhs = unpack!(block = this.as_local_operand(block, rhs));
+                    let rhs = unpack!(block = this.as_local_rvalue(block, rhs));
                     let lhs = unpack!(block = this.as_place(block, lhs));
                     unpack!(block = this.build_drop_and_replace(block, lhs_span, lhs, rhs));
                 } else {
diff --git a/compiler/rustc_mir_build/src/build/scope.rs b/compiler/rustc_mir_build/src/build/scope.rs
index 591b416337b..770701b3750 100644
--- a/compiler/rustc_mir_build/src/build/scope.rs
+++ b/compiler/rustc_mir_build/src/build/scope.rs
@@ -91,7 +91,7 @@ use rustc_middle::middle::region;
 use rustc_middle::mir::*;
 use rustc_middle::thir::{Expr, LintLevel};
 
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::{DesugaringKind, Span, DUMMY_SP};
 
 #[derive(Debug)]
 pub struct Scopes<'tcx> {
@@ -1118,24 +1118,35 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     }
 
     /// Utility function for *non*-scope code to build their own drops
+    /// Force a drop at this point in the MIR by creating a new block.
     pub(crate) fn build_drop_and_replace(
         &mut self,
         block: BasicBlock,
         span: Span,
         place: Place<'tcx>,
-        value: Operand<'tcx>,
+        value: Rvalue<'tcx>,
     ) -> BlockAnd<()> {
+        let span = self.tcx.with_stable_hashing_context(|hcx| {
+            span.mark_with_reason(None, DesugaringKind::Replace, self.tcx.sess.edition(), hcx)
+        });
         let source_info = self.source_info(span);
-        let next_target = self.cfg.start_new_block();
+
+        // create the new block for the assignment
+        let assign = self.cfg.start_new_block();
+        self.cfg.push_assign(assign, source_info, place, value.clone());
+
+        // create the new block for the assignment in the case of unwinding
+        let assign_unwind = self.cfg.start_new_cleanup_block();
+        self.cfg.push_assign(assign_unwind, source_info, place, value.clone());
 
         self.cfg.terminate(
             block,
             source_info,
-            TerminatorKind::DropAndReplace { place, value, target: next_target, unwind: None },
+            TerminatorKind::Drop { place, target: assign, unwind: Some(assign_unwind) },
         );
         self.diverge_from(block);
 
-        next_target.unit()
+        assign.unit()
     }
 
     /// Creates an `Assert` terminator and return the success block.
@@ -1413,8 +1424,15 @@ impl<'tcx> DropTreeBuilder<'tcx> for Unwind {
     fn add_entry(cfg: &mut CFG<'tcx>, from: BasicBlock, to: BasicBlock) {
         let term = &mut cfg.block_data_mut(from).terminator_mut();
         match &mut term.kind {
-            TerminatorKind::Drop { unwind, .. }
-            | TerminatorKind::DropAndReplace { unwind, .. }
+            TerminatorKind::Drop { unwind, .. } => {
+                if let Some(unwind) = *unwind {
+                    let source_info = term.source_info;
+                    cfg.terminate(unwind, source_info, TerminatorKind::Goto { target: to });
+                } else {
+                    *unwind = Some(to);
+                }
+            }
+            TerminatorKind::DropAndReplace { unwind, .. }
             | TerminatorKind::FalseUnwind { unwind, .. }
             | TerminatorKind::Call { cleanup: unwind, .. }
             | TerminatorKind::Assert { cleanup: unwind, .. }
diff --git a/compiler/rustc_mir_transform/src/elaborate_drops.rs b/compiler/rustc_mir_transform/src/elaborate_drops.rs
index bdfd8dc6e99..29424f09695 100644
--- a/compiler/rustc_mir_transform/src/elaborate_drops.rs
+++ b/compiler/rustc_mir_transform/src/elaborate_drops.rs
@@ -14,7 +14,7 @@ use rustc_mir_dataflow::un_derefer::UnDerefer;
 use rustc_mir_dataflow::MoveDataParamEnv;
 use rustc_mir_dataflow::{on_all_children_bits, on_all_drop_children_bits};
 use rustc_mir_dataflow::{Analysis, ResultsCursor};
-use rustc_span::Span;
+use rustc_span::{DesugaringKind, Span};
 use rustc_target::abi::VariantIdx;
 use std::fmt;
 
@@ -425,10 +425,19 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                             bb,
                         ),
                         LookupResult::Parent(..) => {
-                            self.tcx.sess.delay_span_bug(
-                                terminator.source_info.span,
-                                &format!("drop of untracked value {:?}", bb),
-                            );
+                            if !matches!(
+                                terminator.source_info.span.desugaring_kind(),
+                                Some(DesugaringKind::Replace),
+                            ) {
+                                self.tcx.sess.delay_span_bug(
+                                    terminator.source_info.span,
+                                    &format!("drop of untracked value {:?}", bb),
+                                );
+                            }
+                            // A drop and replace behind a pointer/array/whatever.
+                            // The borrow checker requires that these locations are initialized before the assignment,
+                            // so we just leave an unconditional drop.
+                            assert!(!data.is_cleanup);
                         }
                     }
                 }
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index dee823eefde..9f22e9776d4 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -1151,6 +1151,7 @@ pub enum DesugaringKind {
     Await,
     ForLoop,
     WhileLoop,
+    Replace,
 }
 
 impl DesugaringKind {
@@ -1166,6 +1167,7 @@ impl DesugaringKind {
             DesugaringKind::OpaqueTy => "`impl Trait`",
             DesugaringKind::ForLoop => "`for` loop",
             DesugaringKind::WhileLoop => "`while` loop",
+            DesugaringKind::Replace => "drop and replace",
         }
     }
 }
diff --git a/tests/mir-opt/basic_assignment.main.ElaborateDrops.diff b/tests/mir-opt/basic_assignment.main.ElaborateDrops.diff
new file mode 100644
index 00000000000..61a934685cd
--- /dev/null
+++ b/tests/mir-opt/basic_assignment.main.ElaborateDrops.diff
@@ -0,0 +1,85 @@
+- // MIR for `main` before ElaborateDrops
++ // MIR for `main` after ElaborateDrops
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/basic_assignment.rs:+0:11: +0:11
+      let _1: bool;                        // in scope 0 at $DIR/basic_assignment.rs:+1:9: +1:17
+      let mut _3: bool;                    // in scope 0 at $DIR/basic_assignment.rs:+6:16: +6:24
+      let mut _6: std::option::Option<std::boxed::Box<u32>>; // in scope 0 at $DIR/basic_assignment.rs:+13:14: +13:20
+      scope 1 {
+          debug nodrop_x => _1;            // in scope 1 at $DIR/basic_assignment.rs:+1:9: +1:17
+          let _2: bool;                    // in scope 1 at $DIR/basic_assignment.rs:+2:9: +2:17
+          scope 2 {
+              debug nodrop_y => _2;        // in scope 2 at $DIR/basic_assignment.rs:+2:9: +2:17
+              let _4: std::option::Option<std::boxed::Box<u32>>; // in scope 2 at $DIR/basic_assignment.rs:+8:9: +8:15
+              scope 3 {
+                  debug drop_x => _4;      // in scope 3 at $DIR/basic_assignment.rs:+8:9: +8:15
+                  let _5: std::option::Option<std::boxed::Box<u32>>; // in scope 3 at $DIR/basic_assignment.rs:+9:9: +9:15
+                  scope 4 {
+                      debug drop_y => _5;  // in scope 4 at $DIR/basic_assignment.rs:+9:9: +9:15
+                  }
+              }
+          }
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/basic_assignment.rs:+1:9: +1:17
+          _1 = const false;                // scope 0 at $DIR/basic_assignment.rs:+1:20: +1:25
+          StorageLive(_2);                 // scope 1 at $DIR/basic_assignment.rs:+2:9: +2:17
+          StorageLive(_3);                 // scope 2 at $DIR/basic_assignment.rs:+6:16: +6:24
+          _3 = _1;                         // scope 2 at $DIR/basic_assignment.rs:+6:16: +6:24
+          _2 = move _3;                    // scope 2 at $DIR/basic_assignment.rs:+6:5: +6:24
+          StorageDead(_3);                 // scope 2 at $DIR/basic_assignment.rs:+6:23: +6:24
+          StorageLive(_4);                 // scope 2 at $DIR/basic_assignment.rs:+8:9: +8:15
+          _4 = Option::<Box<u32>>::None;   // scope 2 at $DIR/basic_assignment.rs:+8:36: +8:40
+          StorageLive(_5);                 // scope 3 at $DIR/basic_assignment.rs:+9:9: +9:15
+          StorageLive(_6);                 // scope 4 at $DIR/basic_assignment.rs:+13:14: +13:20
+          _6 = move _4;                    // scope 4 at $DIR/basic_assignment.rs:+13:14: +13:20
+-         drop(_5) -> [return: bb1, unwind: bb2]; // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
++         goto -> bb1;                     // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+      }
+  
+      bb1: {
+          _5 = move _6;                    // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+-         drop(_6) -> [return: bb3, unwind: bb6]; // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
++         goto -> bb3;                     // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
+      }
+  
+      bb2 (cleanup): {
+          _5 = move _6;                    // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+          drop(_6) -> bb6;                 // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
+      }
+  
+      bb3: {
+          StorageDead(_6);                 // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
+          _0 = const ();                   // scope 0 at $DIR/basic_assignment.rs:+0:11: +14:2
+          drop(_5) -> [return: bb4, unwind: bb7]; // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
+      }
+  
+      bb4: {
+          StorageDead(_5);                 // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
+-         drop(_4) -> bb5;                 // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
++         goto -> bb5;                     // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
+      }
+  
+      bb5: {
+          StorageDead(_4);                 // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
+          StorageDead(_2);                 // scope 1 at $DIR/basic_assignment.rs:+14:1: +14:2
+          StorageDead(_1);                 // scope 0 at $DIR/basic_assignment.rs:+14:1: +14:2
+          return;                          // scope 0 at $DIR/basic_assignment.rs:+14:2: +14:2
+      }
+  
+      bb6 (cleanup): {
+          drop(_5) -> bb7;                 // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
+      }
+  
+      bb7 (cleanup): {
+-         drop(_4) -> bb8;                 // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
++         goto -> bb8;                     // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
+      }
+  
+      bb8 (cleanup): {
+          resume;                          // scope 0 at $DIR/basic_assignment.rs:+0:1: +14:2
+      }
+  }
+  
diff --git a/tests/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir b/tests/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir
index 1f099cd5e83..9e7f5f21284 100644
--- a/tests/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir
+++ b/tests/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir
@@ -1,8 +1,8 @@
 // MIR for `main` after SimplifyCfg-initial
 
 | User Type Annotations
-| 0: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:18:17: 18:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
-| 1: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:18:17: 18:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
+| 0: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:19:17: 19:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
+| 1: user_ty: Canonical { max_universe: U0, variables: [], value: Ty(std::option::Option<std::boxed::Box<u32>>) }, span: $DIR/basic_assignment.rs:19:17: 19:33, inferred_ty: std::option::Option<std::boxed::Box<u32>>
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/basic_assignment.rs:+0:11: +0:11
@@ -41,35 +41,37 @@ fn main() -> () {
         StorageLive(_5);                 // scope 3 at $DIR/basic_assignment.rs:+9:9: +9:15
         StorageLive(_6);                 // scope 4 at $DIR/basic_assignment.rs:+13:14: +13:20
         _6 = move _4;                    // scope 4 at $DIR/basic_assignment.rs:+13:14: +13:20
-        replace(_5 <- move _6) -> [return: bb1, unwind: bb5]; // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+        drop(_5) -> [return: bb1, unwind: bb2]; // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
     }
 
     bb1: {
-        drop(_6) -> [return: bb2, unwind: bb6]; // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
+        _5 = move _6;                    // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+        drop(_6) -> [return: bb3, unwind: bb6]; // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
     }
 
-    bb2: {
+    bb2 (cleanup): {
+        _5 = move _6;                    // scope 4 at $DIR/basic_assignment.rs:+13:5: +13:11
+        drop(_6) -> bb6;                 // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
+    }
+
+    bb3: {
         StorageDead(_6);                 // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
         _0 = const ();                   // scope 0 at $DIR/basic_assignment.rs:+0:11: +14:2
-        drop(_5) -> [return: bb3, unwind: bb7]; // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
+        drop(_5) -> [return: bb4, unwind: bb7]; // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
     }
 
-    bb3: {
+    bb4: {
         StorageDead(_5);                 // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
-        drop(_4) -> [return: bb4, unwind: bb8]; // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
+        drop(_4) -> [return: bb5, unwind: bb8]; // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
     }
 
-    bb4: {
+    bb5: {
         StorageDead(_4);                 // scope 2 at $DIR/basic_assignment.rs:+14:1: +14:2
         StorageDead(_2);                 // scope 1 at $DIR/basic_assignment.rs:+14:1: +14:2
         StorageDead(_1);                 // scope 0 at $DIR/basic_assignment.rs:+14:1: +14:2
         return;                          // scope 0 at $DIR/basic_assignment.rs:+14:2: +14:2
     }
 
-    bb5 (cleanup): {
-        drop(_6) -> bb6;                 // scope 4 at $DIR/basic_assignment.rs:+13:19: +13:20
-    }
-
     bb6 (cleanup): {
         drop(_5) -> bb7;                 // scope 3 at $DIR/basic_assignment.rs:+14:1: +14:2
     }
diff --git a/tests/mir-opt/basic_assignment.rs b/tests/mir-opt/basic_assignment.rs
index ac350271e9f..2a52323c2ce 100644
--- a/tests/mir-opt/basic_assignment.rs
+++ b/tests/mir-opt/basic_assignment.rs
@@ -1,5 +1,6 @@
 // this tests move up progration, which is not yet implemented
 
+// EMIT_MIR basic_assignment.main.ElaborateDrops.diff
 // EMIT_MIR basic_assignment.main.SimplifyCfg-initial.after.mir
 
 // Check codegen for assignments (`a = b`) where the left-hand-side is
diff --git a/tests/mir-opt/issue_41110.test.ElaborateDrops.diff b/tests/mir-opt/issue_41110.test.ElaborateDrops.diff
index 79e3d073be5..3dd1a9bbab5 100644
--- a/tests/mir-opt/issue_41110.test.ElaborateDrops.diff
+++ b/tests/mir-opt/issue_41110.test.ElaborateDrops.diff
@@ -38,37 +38,39 @@
           StorageLive(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
 +         _6 = const false;                // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
           _5 = move _1;                    // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
--         replace(_2 <- move _5) -> [return: bb2, unwind: bb6]; // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-+         goto -> bb12;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
+-         drop(_2) -> [return: bb2, unwind: bb3]; // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
++         goto -> bb2;                     // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
       }
   
       bb2: {
--         drop(_5) -> [return: bb3, unwind: bb8]; // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-+         goto -> bb3;                     // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+          _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
+-         drop(_5) -> [return: bb4, unwind: bb8]; // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
++         goto -> bb4;                     // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
+      }
+  
+      bb3 (cleanup): {
+          _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
+          drop(_5) -> bb8;                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
       }
   
-      bb3: {
+      bb4: {
           StorageDead(_5);                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
           _0 = const ();                   // scope 0 at $DIR/issue_41110.rs:+0:15: +5:2
-          drop(_2) -> [return: bb4, unwind: bb9]; // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
+          drop(_2) -> [return: bb5, unwind: bb9]; // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
       }
   
-      bb4: {
+      bb5: {
           StorageDead(_2);                 // scope 1 at $DIR/issue_41110.rs:+5:1: +5:2
--         drop(_1) -> bb5;                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-+         goto -> bb5;                     // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
+-         drop(_1) -> bb6;                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++         goto -> bb6;                     // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
       }
   
-      bb5: {
+      bb6: {
 +         _6 = const false;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
           StorageDead(_1);                 // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
           return;                          // scope 0 at $DIR/issue_41110.rs:+5:2: +5:2
       }
   
-      bb6 (cleanup): {
-          drop(_5) -> bb8;                 // scope 2 at $DIR/issue_41110.rs:+4:9: +4:10
-      }
-  
       bb7 (cleanup): {
 -         drop(_4) -> bb8;                 // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
 +         goto -> bb8;                     // scope 2 at $DIR/issue_41110.rs:+3:11: +3:12
@@ -81,7 +83,7 @@
   
       bb9 (cleanup): {
 -         drop(_1) -> bb10;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
-+         goto -> bb14;                    // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++         goto -> bb12;                    // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
       }
   
       bb10 (cleanup): {
@@ -89,21 +91,11 @@
 +     }
 + 
 +     bb11 (cleanup): {
-+         _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-+         goto -> bb10;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-+     }
-+ 
-+     bb12: {
-+         _2 = move _5;                    // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-+         goto -> bb2;                     // scope 2 at $DIR/issue_41110.rs:+4:5: +4:6
-+     }
-+ 
-+     bb13 (cleanup): {
 +         drop(_1) -> bb10;                // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
 +     }
 + 
-+     bb14 (cleanup): {
-+         switchInt(_6) -> [0: bb10, otherwise: bb13]; // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
++     bb12 (cleanup): {
++         switchInt(_6) -> [0: bb10, otherwise: bb11]; // scope 0 at $DIR/issue_41110.rs:+5:1: +5:2
       }
   }
   
diff --git a/tests/mir-opt/issue_41888.main.ElaborateDrops.diff b/tests/mir-opt/issue_41888.main.ElaborateDrops.diff
index 257f0b1e6e8..4e38659a90b 100644
--- a/tests/mir-opt/issue_41888.main.ElaborateDrops.diff
+++ b/tests/mir-opt/issue_41888.main.ElaborateDrops.diff
@@ -34,7 +34,7 @@
       }
   
       bb1: {
-          switchInt(move _2) -> [0: bb7, otherwise: bb2]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
+          switchInt(move _2) -> [0: bb8, otherwise: bb2]; // scope 1 at $DIR/issue_41888.rs:+2:8: +2:14
       }
   
       bb2: {
@@ -43,47 +43,56 @@
           _4 = K;                          // scope 1 at $DIR/issue_41888.rs:+3:18: +3:19
           _3 = E::F(move _4);              // scope 1 at $DIR/issue_41888.rs:+3:13: +3:20
           StorageDead(_4);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
--         replace(_1 <- move _3) -> [return: bb3, unwind: bb10]; // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         goto -> bb14;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
+-         drop(_1) -> [return: bb3, unwind: bb4]; // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         goto -> bb3;                     // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
       }
   
       bb3: {
--         drop(_3) -> [return: bb4, unwind: bb11]; // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-+         goto -> bb4;                     // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
++         _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
++         _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
+          _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
+-         drop(_3) -> [return: bb5, unwind: bb11]; // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
++         goto -> bb5;                     // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
+      }
+  
+      bb4 (cleanup): {
+          _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
+          drop(_3) -> bb11;                // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
       }
   
-      bb4: {
+      bb5: {
           StorageDead(_3);                 // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
           _5 = discriminant(_1);           // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
-          switchInt(move _5) -> [0: bb5, otherwise: bb6]; // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
+          switchInt(move _5) -> [0: bb6, otherwise: bb7]; // scope 2 at $DIR/issue_41888.rs:+4:16: +4:24
       }
   
-      bb5: {
+      bb6: {
           StorageLive(_6);                 // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
 +         _9 = const false;                // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
           _6 = move ((_1 as F).0: K);      // scope 2 at $DIR/issue_41888.rs:+4:21: +4:23
           _0 = const ();                   // scope 2 at $DIR/issue_41888.rs:+4:29: +7:10
           StorageDead(_6);                 // scope 1 at $DIR/issue_41888.rs:+7:9: +7:10
-          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
+          goto -> bb9;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
       }
   
-      bb6: {
+      bb7: {
           _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+7:10: +7:10
-          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
+          goto -> bb9;                     // scope 1 at $DIR/issue_41888.rs:+4:9: +7:10
       }
   
-      bb7: {
+      bb8: {
           _0 = const ();                   // scope 1 at $DIR/issue_41888.rs:+8:6: +8:6
-          goto -> bb8;                     // scope 1 at $DIR/issue_41888.rs:+2:5: +8:6
+          goto -> bb9;                     // scope 1 at $DIR/issue_41888.rs:+2:5: +8:6
       }
   
-      bb8: {
+      bb9: {
           StorageDead(_2);                 // scope 1 at $DIR/issue_41888.rs:+8:5: +8:6
--         drop(_1) -> bb9;                 // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-+         goto -> bb20;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
+-         drop(_1) -> bb10;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         goto -> bb18;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
       }
   
-      bb9: {
+      bb10: {
 +         _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +         _8 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +         _9 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
@@ -91,10 +100,6 @@
           return;                          // scope 0 at $DIR/issue_41888.rs:+9:2: +9:2
       }
   
-      bb10 (cleanup): {
-          drop(_3) -> bb11;                // scope 1 at $DIR/issue_41888.rs:+3:19: +3:20
-      }
-  
       bb11 (cleanup): {
 -         drop(_1) -> bb12;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +         goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
@@ -104,55 +109,39 @@
           resume;                          // scope 0 at $DIR/issue_41888.rs:+0:1: +9:2
 +     }
 + 
-+     bb13 (cleanup): {
-+         _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         goto -> bb12;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+     }
-+ 
-+     bb14: {
-+         _7 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _8 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _9 = const true;                 // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         _1 = move _3;                    // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+         goto -> bb3;                     // scope 1 at $DIR/issue_41888.rs:+3:9: +3:10
-+     }
-+ 
-+     bb15: {
++     bb13: {
 +         _7 = const false;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-+         goto -> bb9;                     // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         goto -> bb10;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb16 (cleanup): {
++     bb14 (cleanup): {
 +         goto -> bb12;                    // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb17: {
-+         drop(_1) -> [return: bb15, unwind: bb12]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     bb15: {
++         drop(_1) -> [return: bb13, unwind: bb12]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb18 (cleanup): {
++     bb16 (cleanup): {
 +         drop(_1) -> bb12;                // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb19: {
++     bb17: {
 +         _10 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-+         switchInt(move _10) -> [0: bb15, otherwise: bb17]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         switchInt(move _10) -> [0: bb13, otherwise: bb15]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb20: {
-+         switchInt(_7) -> [0: bb15, otherwise: bb19]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     bb18: {
++         switchInt(_7) -> [0: bb13, otherwise: bb17]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb21 (cleanup): {
++     bb19 (cleanup): {
 +         _11 = discriminant(_1);          // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
-+         switchInt(move _11) -> [0: bb16, otherwise: bb18]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++         switchInt(move _11) -> [0: bb14, otherwise: bb16]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
 +     }
 + 
-+     bb22 (cleanup): {
-+         switchInt(_7) -> [0: bb12, otherwise: bb21]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
++     bb20 (cleanup): {
++         switchInt(_7) -> [0: bb12, otherwise: bb19]; // scope 0 at $DIR/issue_41888.rs:+9:1: +9:2
       }
   }
   
diff --git a/tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir b/tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
index 210f178a0a9..56cb9166c37 100644
--- a/tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
+++ b/tests/mir-opt/packed_struct_drop_aligned.main.SimplifyCfg-elaborate-drops.after.mir
@@ -28,21 +28,21 @@ fn main() -> () {
         StorageDead(_5);                 // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:28: +2:29
         StorageLive(_6);                 // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
         _6 = move (_1.0: Aligned);       // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
-        drop(_6) -> [return: bb4, unwind: bb3]; // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
+        drop(_6) -> [return: bb4, unwind: bb1]; // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
     }
 
-    bb1: {
-        StorageDead(_1);                 // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
-        return;                          // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:2: +3:2
+    bb1 (cleanup): {
+        (_1.0: Aligned) = move _4;       // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
+        drop(_1) -> bb3;                 // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
     }
 
-    bb2 (cleanup): {
-        resume;                          // scope 0 at $DIR/packed_struct_drop_aligned.rs:+0:1: +3:2
+    bb2: {
+        StorageDead(_1);                 // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
+        return;                          // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:2: +3:2
     }
 
     bb3 (cleanup): {
-        (_1.0: Aligned) = move _4;       // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
-        drop(_1) -> bb2;                 // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
+        resume;                          // scope 0 at $DIR/packed_struct_drop_aligned.rs:+0:1: +3:2
     }
 
     bb4: {
@@ -50,6 +50,6 @@ fn main() -> () {
         (_1.0: Aligned) = move _4;       // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:5: +2:8
         StorageDead(_4);                 // scope 1 at $DIR/packed_struct_drop_aligned.rs:+2:28: +2:29
         _0 = const ();                   // scope 0 at $DIR/packed_struct_drop_aligned.rs:+0:11: +3:2
-        drop(_1) -> [return: bb1, unwind: bb2]; // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
+        drop(_1) -> [return: bb2, unwind: bb3]; // scope 0 at $DIR/packed_struct_drop_aligned.rs:+3:1: +3:2
     }
 }
diff --git a/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs b/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs
index 1bda7a49713..127a3f5b2dc 100644
--- a/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs
+++ b/tests/ui/borrowck/borrowck-vec-pattern-nesting.rs
@@ -8,6 +8,7 @@ fn a() {
         //~^ NOTE `vec[_]` is borrowed here
             vec[0] = Box::new(4); //~ ERROR cannot assign
             //~^ NOTE `vec[_]` is assigned to here
+            //~| NOTE in this expansion of desugaring of drop and replace
             _a.use_ref();
             //~^ NOTE borrow later used here
         }
@@ -22,6 +23,7 @@ fn b() {
         //~^ `vec[_]` is borrowed here
             vec[0] = Box::new(4); //~ ERROR cannot assign
             //~^ NOTE `vec[_]` is assigned to here
+            //~| NOTE in this expansion of desugaring of drop and replace
             _b.use_ref();
             //~^ NOTE borrow later used here
         }
diff --git a/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr b/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr
index 70b9e4f4433..5e1251b0590 100644
--- a/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr
+++ b/tests/ui/borrowck/borrowck-vec-pattern-nesting.stderr
@@ -6,24 +6,24 @@ LL |         [box ref _a, _, _] => {
 LL |
 LL |             vec[0] = Box::new(4);
    |             ^^^^^^ `vec[_]` is assigned to here but it was already borrowed
-LL |
+...
 LL |             _a.use_ref();
    |             ------------ borrow later used here
 
 error[E0506]: cannot assign to `vec[_]` because it is borrowed
-  --> $DIR/borrowck-vec-pattern-nesting.rs:23:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:24:13
    |
 LL |         &mut [ref _b @ ..] => {
    |               ------ `vec[_]` is borrowed here
 LL |
 LL |             vec[0] = Box::new(4);
    |             ^^^^^^ `vec[_]` is assigned to here but it was already borrowed
-LL |
+...
 LL |             _b.use_ref();
    |             ------------ borrow later used here
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:34:11
+  --> $DIR/borrowck-vec-pattern-nesting.rs:36:11
    |
 LL |     match vec {
    |           ^^^ cannot move out of here
@@ -41,7 +41,7 @@ LL +         [_a,
    |
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:46:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:48:13
    |
 LL |     let a = vec[0];
    |             ^^^^^^
@@ -55,7 +55,7 @@ LL |     let a = &vec[0];
    |             +
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:55:11
+  --> $DIR/borrowck-vec-pattern-nesting.rs:57:11
    |
 LL |     match vec {
    |           ^^^ cannot move out of here
@@ -73,7 +73,7 @@ LL +         [
    |
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:65:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:67:13
    |
 LL |     let a = vec[0];
    |             ^^^^^^
@@ -87,7 +87,7 @@ LL |     let a = &vec[0];
    |             +
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:74:11
+  --> $DIR/borrowck-vec-pattern-nesting.rs:76:11
    |
 LL |     match vec {
    |           ^^^ cannot move out of here
@@ -106,7 +106,7 @@ LL +         [_a, _b, _c] => {}
    |
 
 error[E0508]: cannot move out of type `[Box<isize>]`, a non-copy slice
-  --> $DIR/borrowck-vec-pattern-nesting.rs:85:13
+  --> $DIR/borrowck-vec-pattern-nesting.rs:87:13
    |
 LL |     let a = vec[0];
    |             ^^^^^^
diff --git a/tests/ui/borrowck/issue-45199.rs b/tests/ui/borrowck/issue-45199.rs
index ded46e56e34..6a6b25541f3 100644
--- a/tests/ui/borrowck/issue-45199.rs
+++ b/tests/ui/borrowck/issue-45199.rs
@@ -5,6 +5,7 @@ fn test_drop_replace() {
     b = Box::new(1);    //~ NOTE first assignment
     b = Box::new(2);    //~ ERROR cannot assign twice to immutable variable `b`
                         //~| NOTE cannot assign twice to immutable
+                        //~| NOTE in this expansion of desugaring of drop and replace
 }
 
 fn test_call() {
@@ -13,12 +14,14 @@ fn test_call() {
                             //~| SUGGESTION mut b
     b = Box::new(2);        //~ ERROR cannot assign twice to immutable variable `b`
                             //~| NOTE cannot assign twice to immutable
+                            //~| NOTE in this expansion of desugaring of drop and replace
 }
 
 fn test_args(b: Box<i32>) {  //~ HELP consider making this binding mutable
                                 //~| SUGGESTION mut b
     b = Box::new(2);            //~ ERROR cannot assign to immutable argument `b`
                                 //~| NOTE cannot assign to immutable argument
+                                //~| NOTE in this expansion of desugaring of drop and replace
 }
 
 fn main() {}
diff --git a/tests/ui/borrowck/issue-45199.stderr b/tests/ui/borrowck/issue-45199.stderr
index 47aa3090827..163f2370ba0 100644
--- a/tests/ui/borrowck/issue-45199.stderr
+++ b/tests/ui/borrowck/issue-45199.stderr
@@ -10,7 +10,7 @@ LL |     b = Box::new(2);
    |     ^ cannot assign twice to immutable variable
 
 error[E0384]: cannot assign twice to immutable variable `b`
-  --> $DIR/issue-45199.rs:14:5
+  --> $DIR/issue-45199.rs:15:5
    |
 LL |     let b = Box::new(1);
    |         -
@@ -22,7 +22,7 @@ LL |     b = Box::new(2);
    |     ^ cannot assign twice to immutable variable
 
 error[E0384]: cannot assign to immutable argument `b`
-  --> $DIR/issue-45199.rs:20:5
+  --> $DIR/issue-45199.rs:22:5
    |
 LL | fn test_args(b: Box<i32>) {
    |              - help: consider making this binding mutable: `mut b`
diff --git a/tests/ui/borrowck/issue-58776-borrowck-scans-children.rs b/tests/ui/borrowck/issue-58776-borrowck-scans-children.rs
index efa313a9d23..0b2372d1274 100644
--- a/tests/ui/borrowck/issue-58776-borrowck-scans-children.rs
+++ b/tests/ui/borrowck/issue-58776-borrowck-scans-children.rs
@@ -5,7 +5,6 @@ fn main() {
     greeting = "DEALLOCATED".to_string();
     //~^ ERROR cannot assign
     drop(greeting);
-    //~^ ERROR cannot move
 
     println!("thread result: {:?}", res);
 }
diff --git a/tests/ui/borrowck/issue-58776-borrowck-scans-children.stderr b/tests/ui/borrowck/issue-58776-borrowck-scans-children.stderr
index 0870b423769..967451c68be 100644
--- a/tests/ui/borrowck/issue-58776-borrowck-scans-children.stderr
+++ b/tests/ui/borrowck/issue-58776-borrowck-scans-children.stderr
@@ -12,21 +12,6 @@ LL |     greeting = "DEALLOCATED".to_string();
 LL |     println!("thread result: {:?}", res);
    |                                     --- borrow later used here
 
-error[E0505]: cannot move out of `greeting` because it is borrowed
-  --> $DIR/issue-58776-borrowck-scans-children.rs:7:10
-   |
-LL |     let res = (|| (|| &greeting)())();
-   |                --      -------- borrow occurs due to use in closure
-   |                |
-   |                borrow of `greeting` occurs here
-...
-LL |     drop(greeting);
-   |          ^^^^^^^^ move out of `greeting` occurs here
-...
-LL |     println!("thread result: {:?}", res);
-   |                                     --- borrow later used here
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0505, E0506.
-For more information about an error, try `rustc --explain E0505`.
+For more information about this error, try `rustc --explain E0506`.
diff --git a/tests/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs b/tests/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
index c9b16e43910..293fdca1cc9 100644
--- a/tests/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
+++ b/tests/ui/liveness/liveness-assign/liveness-assign-imm-local-with-drop.rs
@@ -5,6 +5,7 @@ fn test() {
     drop(b);
     b = Box::new(2); //~ ERROR cannot assign twice to immutable variable `b`
                      //~| NOTE cannot assign twice to immutable
+                     //~| NOTE in this expansion of desugaring of drop and replace
     drop(b);
 }