Auto merge of #97931 - xldenis:fix-if-let-source-scopes, r=nagisa

Fix `SourceScope` for `if let` bindings.

Fixes #97799.

I'm not sure how to test this properly, is there any way to observe the difference in behavior apart from `ui` tests? I'm worried that they would be overlooked in the case of a regression.

16 files changed, 330 insertions, 177 deletions

diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index ccbb518e72d..cffb67ef013 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -63,6 +63,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         (if_then_scope, then_source_info),
                         LintLevel::Inherited,
                         |this| {
+                            let source_info = if this.is_let(cond) {
+                                let variable_scope = this.new_source_scope(
+                                    then_expr.span,
+                                    LintLevel::Inherited,
+                                    None,
+                                );
+                                this.source_scope = variable_scope;
+                                SourceInfo { span: then_expr.span, scope: variable_scope }
+                            } else {
+                                this.source_info(then_expr.span)
+                            };
                             let (then_block, else_block) =
                                 this.in_if_then_scope(condition_scope, |this| {
                                     let then_blk = unpack!(this.then_else_break(
@@ -70,8 +81,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                                         &this.thir[cond],
                                         Some(condition_scope),
                                         condition_scope,
-                                        then_expr.span,
+                                        source_info
                                     ));
+
                                     this.expr_into_dest(destination, then_blk, then_expr)
                                 });
                             then_block.and(else_block)
@@ -97,7 +109,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ExprKind::Let { expr, ref pat } => {
                 let scope = this.local_scope();
                 let (true_block, false_block) = this.in_if_then_scope(scope, |this| {
-                    this.lower_let_expr(block, &this.thir[expr], pat, scope, expr_span)
+                    this.lower_let_expr(block, &this.thir[expr], pat, scope, None, expr_span)
                 });
 
                 this.cfg.push_assign_constant(
@@ -575,4 +587,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
         block_and
     }
+
+    fn is_let(&self, expr: ExprId) -> bool {
+        match self.thir[expr].kind {
+            ExprKind::Let { .. } => true,
+            ExprKind::Scope { value, .. } => self.is_let(value),
+            _ => false,
+        }
+    }
 }
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index dc1860cb112..1628f1a4b85 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -40,7 +40,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         expr: &Expr<'tcx>,
         temp_scope_override: Option<region::Scope>,
         break_scope: region::Scope,
-        variable_scope_span: Span,
+        variable_source_info: SourceInfo,
     ) -> BlockAnd<()> {
         let this = self;
         let expr_span = expr.span;
@@ -52,7 +52,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     &this.thir[lhs],
                     temp_scope_override,
                     break_scope,
-                    variable_scope_span,
+                    variable_source_info,
                 ));
 
                 let rhs_then_block = unpack!(this.then_else_break(
@@ -60,7 +60,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     &this.thir[rhs],
                     temp_scope_override,
                     break_scope,
-                    variable_scope_span,
+                    variable_source_info,
                 ));
 
                 rhs_then_block.unit()
@@ -73,13 +73,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         &this.thir[value],
                         temp_scope_override,
                         break_scope,
-                        variable_scope_span,
+                        variable_source_info,
                     )
                 })
             }
-            ExprKind::Let { expr, ref pat } => {
-                this.lower_let_expr(block, &this.thir[expr], pat, break_scope, variable_scope_span)
-            }
+            ExprKind::Let { expr, ref pat } => this.lower_let_expr(
+                block,
+                &this.thir[expr],
+                pat,
+                break_scope,
+                Some(variable_source_info.scope),
+                variable_source_info.span,
+            ),
             _ => {
                 let temp_scope = temp_scope_override.unwrap_or_else(|| this.local_scope());
                 let mutability = Mutability::Mut;
@@ -1772,6 +1777,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         expr: &Expr<'tcx>,
         pat: &Pat<'tcx>,
         else_target: region::Scope,
+        source_scope: Option<SourceScope>,
         span: Span,
     ) -> BlockAnd<()> {
         let expr_span = expr.span;
@@ -1797,7 +1803,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let otherwise_post_guard_block = otherwise_candidate.pre_binding_block.unwrap();
         self.break_for_else(otherwise_post_guard_block, else_target, self.source_info(expr_span));
 
-        self.declare_bindings(None, pat.span.to(span), pat, ArmHasGuard(false), opt_expr_place);
+        self.declare_bindings(
+            source_scope,
+            pat.span.to(span),
+            pat,
+            ArmHasGuard(false),
+            opt_expr_place,
+        );
+
         let post_guard_block = self.bind_pattern(
             self.source_info(pat.span),
             guard_candidate,
@@ -1969,12 +1982,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     Guard::If(e) => {
                         let e = &this.thir[e];
                         guard_span = e.span;
-                        this.then_else_break(block, e, None, match_scope, arm_span)
+                        this.then_else_break(
+                            block,
+                            e,
+                            None,
+                            match_scope,
+                            this.source_info(arm_span),
+                        )
                     }
                     Guard::IfLet(ref pat, scrutinee) => {
                         let s = &this.thir[scrutinee];
                         guard_span = s.span;
-                        this.lower_let_expr(block, s, pat, match_scope, arm_span)
+                        this.lower_let_expr(block, s, pat, match_scope, None, arm_span)
                     }
                 });
 
diff --git a/src/test/debuginfo/lexical-scope-in-if-let.rs b/src/test/debuginfo/lexical-scope-in-if-let.rs
new file mode 100644
index 00000000000..cdc37ce48fb
--- /dev/null
+++ b/src/test/debuginfo/lexical-scope-in-if-let.rs
@@ -0,0 +1,100 @@
+// compile-flags:-g
+
+// === GDB TESTS ==================================================================================
+
+// gdb-command:run
+// gdb-command:info locals
+// gdb-check:a = 123
+
+// gdb-command:continue
+// gdb-command:info locals
+// gdb-check:x = 42
+// gdb-check:a = 123
+
+// gdb-command:continue
+// gdb-command:info locals
+// gdb-check:y = true
+// gdb-check:b = 456
+// gdb-check:x = 42
+// gdb-check:a = 123
+
+// gdb-command:continue
+// gdb-command:info locals
+// gdb-check:z = 10
+// gdb-check:c = 789
+// gdb-check:y = true
+// gdb-check:b = 456
+// gdb-check:x = 42
+// gdb-check:a = 123
+
+// === LLDB TESTS =================================================================================
+
+// lldb-command:run
+// lldb-command:frame variable
+// lldb-check:(int) a = 123
+
+// lldb-command:continue
+// lldb-command:frame variable
+// lldb-check:(int) a = 123 (int) x = 42
+
+// lldb-command:continue
+// lldb-command:frame variable
+// lldb-check:(int) a = 123 (int) x = 42 (int) b = 456 (bool) y = true
+
+// lldb-command:continue
+// lldb-command:frame variable
+// lldb-check:(int) a = 123 (int) x = 42 (int) b = 456 (bool) y = true (int) c = 789 (int) z = 10
+
+// === CDB TESTS ==================================================================================
+
+// cdb-command: g
+// cdb-command: dv
+// cdb-check:[...]a = 0n123
+
+// cdb-command: g
+// cdb-command: dv
+// cdb-check:[...]a = 0n123
+// cdb-check:[...]x = 0n42
+
+// cdb-command: g
+// cdb-command: dv
+// cdb-check:[...]y = true
+// cdb-check:[...]b = 0n456
+// cdb-check:[...]a = 0n123
+// cdb-check:[...]x = 0n42
+
+// cdb-command: g
+// cdb-command: dv
+// cdb-check:[...]z = 0n10
+// cdb-check:[...]c = 0n789
+// cdb-check:[...]y = true
+// cdb-check:[...]b = 0n456
+// cdb-check:[...]a = 0n123
+// cdb-check:[...]x = 0n42
+
+fn main() {
+    let a = id(123);
+
+    zzz(); // #break
+
+    if let Some(x) = id(Some(42)) {
+        zzz(); // #break
+
+        let b = id(456);
+
+        if let Ok(y) = id::<Result<bool, ()>>(Ok(true)) {
+            zzz(); // #break
+
+            let c = id(789);
+
+            if let (z, 42) = id((10, 42)) {
+                zzz(); // #break
+            }
+        }
+    }
+}
+
+#[inline(never)]
+fn id<T>(value: T) -> T { value }
+
+fn zzz() { }
diff --git a/src/test/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff b/src/test/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
index 445732f7022..047853696f2 100644
--- a/src/test/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
+++ b/src/test/mir-opt/const_prop/discriminant.main.ConstProp.32bit.diff
@@ -10,26 +10,28 @@
       scope 1 {
           debug x => _1;                   // in scope 1 at $DIR/discriminant.rs:11:9: 11:10
       }
+      scope 2 {
+      }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/discriminant.rs:11:9: 11:10
           StorageLive(_2);                 // scope 0 at $DIR/discriminant.rs:11:13: 11:64
-          StorageLive(_3);                 // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          Deinit(_3);                      // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          ((_3 as Some).0: bool) = const true; // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          discriminant(_3) = 1;            // scope 0 at $DIR/discriminant.rs:11:34: 11:44
--         _4 = discriminant(_3);           // scope 0 at $DIR/discriminant.rs:11:21: 11:31
--         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
-+         _4 = const 1_isize;              // scope 0 at $DIR/discriminant.rs:11:21: 11:31
-+         switchInt(const 1_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
+          StorageLive(_3);                 // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          Deinit(_3);                      // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          ((_3 as Some).0: bool) = const true; // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          discriminant(_3) = 1;            // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+-         _4 = discriminant(_3);           // scope 2 at $DIR/discriminant.rs:11:21: 11:31
+-         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
++         _4 = const 1_isize;              // scope 2 at $DIR/discriminant.rs:11:21: 11:31
++         switchInt(const 1_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
       }
   
       bb1: {
-          switchInt(((_3 as Some).0: bool)) -> [false: bb3, otherwise: bb2]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
+          switchInt(((_3 as Some).0: bool)) -> [false: bb3, otherwise: bb2]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
       }
   
       bb2: {
-          _2 = const 42_i32;               // scope 0 at $DIR/discriminant.rs:11:47: 11:49
+          _2 = const 42_i32;               // scope 2 at $DIR/discriminant.rs:11:47: 11:49
           goto -> bb4;                     // scope 0 at $DIR/discriminant.rs:11:13: 11:64
       }
   
diff --git a/src/test/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff b/src/test/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
index 445732f7022..047853696f2 100644
--- a/src/test/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
+++ b/src/test/mir-opt/const_prop/discriminant.main.ConstProp.64bit.diff
@@ -10,26 +10,28 @@
       scope 1 {
           debug x => _1;                   // in scope 1 at $DIR/discriminant.rs:11:9: 11:10
       }
+      scope 2 {
+      }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/discriminant.rs:11:9: 11:10
           StorageLive(_2);                 // scope 0 at $DIR/discriminant.rs:11:13: 11:64
-          StorageLive(_3);                 // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          Deinit(_3);                      // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          ((_3 as Some).0: bool) = const true; // scope 0 at $DIR/discriminant.rs:11:34: 11:44
-          discriminant(_3) = 1;            // scope 0 at $DIR/discriminant.rs:11:34: 11:44
--         _4 = discriminant(_3);           // scope 0 at $DIR/discriminant.rs:11:21: 11:31
--         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
-+         _4 = const 1_isize;              // scope 0 at $DIR/discriminant.rs:11:21: 11:31
-+         switchInt(const 1_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
+          StorageLive(_3);                 // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          Deinit(_3);                      // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          ((_3 as Some).0: bool) = const true; // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+          discriminant(_3) = 1;            // scope 2 at $DIR/discriminant.rs:11:34: 11:44
+-         _4 = discriminant(_3);           // scope 2 at $DIR/discriminant.rs:11:21: 11:31
+-         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
++         _4 = const 1_isize;              // scope 2 at $DIR/discriminant.rs:11:21: 11:31
++         switchInt(const 1_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
       }
   
       bb1: {
-          switchInt(((_3 as Some).0: bool)) -> [false: bb3, otherwise: bb2]; // scope 0 at $DIR/discriminant.rs:11:21: 11:31
+          switchInt(((_3 as Some).0: bool)) -> [false: bb3, otherwise: bb2]; // scope 2 at $DIR/discriminant.rs:11:21: 11:31
       }
   
       bb2: {
-          _2 = const 42_i32;               // scope 0 at $DIR/discriminant.rs:11:47: 11:49
+          _2 = const 42_i32;               // scope 2 at $DIR/discriminant.rs:11:47: 11:49
           goto -> bb4;                     // scope 0 at $DIR/discriminant.rs:11:13: 11:64
       }
   
diff --git a/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff b/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
index 1efaba044ec..982dd7a27bc 100644
--- a/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
+++ b/src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
@@ -7,22 +7,24 @@
       let mut _2: isize;                   // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:20: 13:30
       let mut _3: isize;                   // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
       let mut _4: &E;                      // in scope 0 at $DIR/early_otherwise_branch_soundness.rs:12:16: 12:17
+      scope 1 {
+      }
   
       bb0: {
-          _3 = discriminant((*_1));        // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
-          switchInt(move _3) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          _3 = discriminant((*_1));        // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          switchInt(move _3) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
       }
   
       bb1: {
-          StorageLive(_4);                 // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
-          _4 = move (((*_1) as Some).0: &E); // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
-          _2 = discriminant((*_4));        // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
-          StorageDead(_4);                 // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
-          switchInt(move _2) -> [1_isize: bb2, otherwise: bb3]; // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          StorageLive(_4);                 // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          _4 = move (((*_1) as Some).0: &E); // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          _2 = discriminant((*_4));        // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          StorageDead(_4);                 // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
+          switchInt(move _2) -> [1_isize: bb2, otherwise: bb3]; // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:12: 13:31
       }
   
       bb2: {
-          _0 = const 1_u32;                // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:38: 13:39
+          _0 = const 1_u32;                // scope 1 at $DIR/early_otherwise_branch_soundness.rs:13:38: 13:39
           goto -> bb4;                     // scope 0 at $DIR/early_otherwise_branch_soundness.rs:13:5: 13:52
       }
   
diff --git a/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff b/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
index f22fbec03d0..15409fa0dd2 100644
--- a/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
+++ b/src/test/mir-opt/funky_arms.float_to_exponential_common.ConstProp.diff
@@ -27,9 +27,9 @@
           let _6: core::num::flt2dec::Sign; // in scope 1 at $DIR/funky_arms.rs:19:9: 19:13
           scope 2 {
               debug sign => _6;            // in scope 2 at $DIR/funky_arms.rs:19:9: 19:13
-              let _10: usize;              // in scope 2 at $DIR/funky_arms.rs:24:17: 24:26
               scope 3 {
                   debug precision => _10;  // in scope 3 at $DIR/funky_arms.rs:24:17: 24:26
+                  let _10: usize;          // in scope 3 at $DIR/funky_arms.rs:24:17: 24:26
               }
           }
       }
@@ -63,52 +63,52 @@
       }
   
       bb4: {
-          StorageLive(_7);                 // scope 2 at $DIR/funky_arms.rs:24:30: 24:45
-          StorageLive(_8);                 // scope 2 at $DIR/funky_arms.rs:24:30: 24:45
-          _8 = &(*_1);                     // scope 2 at $DIR/funky_arms.rs:24:30: 24:45
-          _7 = Formatter::precision(move _8) -> bb5; // scope 2 at $DIR/funky_arms.rs:24:30: 24:45
+          StorageLive(_7);                 // scope 3 at $DIR/funky_arms.rs:24:30: 24:45
+          StorageLive(_8);                 // scope 3 at $DIR/funky_arms.rs:24:30: 24:45
+          _8 = &(*_1);                     // scope 3 at $DIR/funky_arms.rs:24:30: 24:45
+          _7 = Formatter::precision(move _8) -> bb5; // scope 3 at $DIR/funky_arms.rs:24:30: 24:45
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:24:34: 24:43
                                            // + literal: Const { ty: for<'r> fn(&'r Formatter) -> Option<usize> {Formatter::precision}, val: Value(Scalar(<ZST>)) }
       }
   
       bb5: {
-          StorageDead(_8);                 // scope 2 at $DIR/funky_arms.rs:24:44: 24:45
-          _9 = discriminant(_7);           // scope 2 at $DIR/funky_arms.rs:24:12: 24:27
-          switchInt(move _9) -> [1_isize: bb6, otherwise: bb8]; // scope 2 at $DIR/funky_arms.rs:24:12: 24:27
+          StorageDead(_8);                 // scope 3 at $DIR/funky_arms.rs:24:44: 24:45
+          _9 = discriminant(_7);           // scope 3 at $DIR/funky_arms.rs:24:12: 24:27
+          switchInt(move _9) -> [1_isize: bb6, otherwise: bb8]; // scope 3 at $DIR/funky_arms.rs:24:12: 24:27
       }
   
       bb6: {
-          StorageLive(_10);                // scope 2 at $DIR/funky_arms.rs:24:17: 24:26
-          _10 = ((_7 as Some).0: usize);   // scope 2 at $DIR/funky_arms.rs:24:17: 24:26
-          StorageLive(_11);                // scope 2 at $DIR/funky_arms.rs:26:43: 26:46
-          _11 = &mut (*_1);                // scope 2 at $DIR/funky_arms.rs:26:43: 26:46
-          StorageLive(_12);                // scope 2 at $DIR/funky_arms.rs:26:48: 26:51
-          _12 = _2;                        // scope 2 at $DIR/funky_arms.rs:26:48: 26:51
-          StorageLive(_13);                // scope 2 at $DIR/funky_arms.rs:26:53: 26:57
-          _13 = _6;                        // scope 2 at $DIR/funky_arms.rs:26:53: 26:57
-          StorageLive(_14);                // scope 2 at $DIR/funky_arms.rs:26:59: 26:79
-          StorageLive(_15);                // scope 2 at $DIR/funky_arms.rs:26:59: 26:75
-          StorageLive(_16);                // scope 2 at $DIR/funky_arms.rs:26:59: 26:68
-          _16 = _10;                       // scope 2 at $DIR/funky_arms.rs:26:59: 26:68
-          _15 = move _16 as u32 (Misc);    // scope 2 at $DIR/funky_arms.rs:26:59: 26:75
-          StorageDead(_16);                // scope 2 at $DIR/funky_arms.rs:26:74: 26:75
-          _14 = Add(move _15, const 1_u32); // scope 2 at $DIR/funky_arms.rs:26:59: 26:79
-          StorageDead(_15);                // scope 2 at $DIR/funky_arms.rs:26:78: 26:79
-          StorageLive(_17);                // scope 2 at $DIR/funky_arms.rs:26:81: 26:86
-          _17 = _3;                        // scope 2 at $DIR/funky_arms.rs:26:81: 26:86
-          _0 = float_to_exponential_common_exact::<T>(move _11, move _12, move _13, move _14, move _17) -> bb7; // scope 2 at $DIR/funky_arms.rs:26:9: 26:87
+          StorageLive(_10);                // scope 3 at $DIR/funky_arms.rs:24:17: 24:26
+          _10 = ((_7 as Some).0: usize);   // scope 3 at $DIR/funky_arms.rs:24:17: 24:26
+          StorageLive(_11);                // scope 3 at $DIR/funky_arms.rs:26:43: 26:46
+          _11 = &mut (*_1);                // scope 3 at $DIR/funky_arms.rs:26:43: 26:46
+          StorageLive(_12);                // scope 3 at $DIR/funky_arms.rs:26:48: 26:51
+          _12 = _2;                        // scope 3 at $DIR/funky_arms.rs:26:48: 26:51
+          StorageLive(_13);                // scope 3 at $DIR/funky_arms.rs:26:53: 26:57
+          _13 = _6;                        // scope 3 at $DIR/funky_arms.rs:26:53: 26:57
+          StorageLive(_14);                // scope 3 at $DIR/funky_arms.rs:26:59: 26:79
+          StorageLive(_15);                // scope 3 at $DIR/funky_arms.rs:26:59: 26:75
+          StorageLive(_16);                // scope 3 at $DIR/funky_arms.rs:26:59: 26:68
+          _16 = _10;                       // scope 3 at $DIR/funky_arms.rs:26:59: 26:68
+          _15 = move _16 as u32 (Misc);    // scope 3 at $DIR/funky_arms.rs:26:59: 26:75
+          StorageDead(_16);                // scope 3 at $DIR/funky_arms.rs:26:74: 26:75
+          _14 = Add(move _15, const 1_u32); // scope 3 at $DIR/funky_arms.rs:26:59: 26:79
+          StorageDead(_15);                // scope 3 at $DIR/funky_arms.rs:26:78: 26:79
+          StorageLive(_17);                // scope 3 at $DIR/funky_arms.rs:26:81: 26:86
+          _17 = _3;                        // scope 3 at $DIR/funky_arms.rs:26:81: 26:86
+          _0 = float_to_exponential_common_exact::<T>(move _11, move _12, move _13, move _14, move _17) -> bb7; // scope 3 at $DIR/funky_arms.rs:26:9: 26:87
                                            // mir::Constant
                                            // + span: $DIR/funky_arms.rs:26:9: 26:42
                                            // + literal: Const { ty: for<'r, 's, 't0> fn(&'r mut Formatter<'s>, &'t0 T, Sign, u32, bool) -> Result<(), std::fmt::Error> {float_to_exponential_common_exact::<T>}, val: Value(Scalar(<ZST>)) }
       }
   
       bb7: {
-          StorageDead(_17);                // scope 2 at $DIR/funky_arms.rs:26:86: 26:87
-          StorageDead(_14);                // scope 2 at $DIR/funky_arms.rs:26:86: 26:87
-          StorageDead(_13);                // scope 2 at $DIR/funky_arms.rs:26:86: 26:87
-          StorageDead(_12);                // scope 2 at $DIR/funky_arms.rs:26:86: 26:87
-          StorageDead(_11);                // scope 2 at $DIR/funky_arms.rs:26:86: 26:87
+          StorageDead(_17);                // scope 3 at $DIR/funky_arms.rs:26:86: 26:87
+          StorageDead(_14);                // scope 3 at $DIR/funky_arms.rs:26:86: 26:87
+          StorageDead(_13);                // scope 3 at $DIR/funky_arms.rs:26:86: 26:87
+          StorageDead(_12);                // scope 3 at $DIR/funky_arms.rs:26:86: 26:87
+          StorageDead(_11);                // scope 3 at $DIR/funky_arms.rs:26:86: 26:87
           StorageDead(_10);                // scope 2 at $DIR/funky_arms.rs:27:5: 27:6
           goto -> bb10;                    // scope 2 at $DIR/funky_arms.rs:24:5: 29:6
       }
diff --git a/src/test/mir-opt/issue_41888.main.ElaborateDrops.after.mir b/src/test/mir-opt/issue_41888.main.ElaborateDrops.after.mir
index 54930937c91..ce7ca20358e 100644
--- a/src/test/mir-opt/issue_41888.main.ElaborateDrops.after.mir
+++ b/src/test/mir-opt/issue_41888.main.ElaborateDrops.after.mir
@@ -14,9 +14,9 @@ fn main() -> () {
     let mut _11: isize;                  // in scope 0 at $DIR/issue-41888.rs:15:1: 15:2
     scope 1 {
         debug e => _1;                   // in scope 1 at $DIR/issue-41888.rs:7:9: 7:10
-        let _6: K;                       // in scope 1 at $DIR/issue-41888.rs:10:21: 10:23
         scope 2 {
             debug _k => _6;              // in scope 2 at $DIR/issue-41888.rs:10:21: 10:23
+            let _6: K;                   // in scope 2 at $DIR/issue-41888.rs:10:21: 10:23
         }
     }
 
@@ -51,15 +51,15 @@ fn main() -> () {
 
     bb4: {
         StorageDead(_3);                 // scope 1 at $DIR/issue-41888.rs:9:19: 9:20
-        _5 = discriminant(_1);           // scope 1 at $DIR/issue-41888.rs:10:16: 10:24
-        switchInt(move _5) -> [0_isize: bb5, otherwise: bb6]; // scope 1 at $DIR/issue-41888.rs:10:16: 10:24
+        _5 = discriminant(_1);           // scope 2 at $DIR/issue-41888.rs:10:16: 10:24
+        switchInt(move _5) -> [0_isize: bb5, otherwise: bb6]; // scope 2 at $DIR/issue-41888.rs:10:16: 10:24
     }
 
     bb5: {
-        StorageLive(_6);                 // scope 1 at $DIR/issue-41888.rs:10:21: 10:23
-        _9 = const false;                // scope 1 at $DIR/issue-41888.rs:10:21: 10:23
-        _6 = move ((_1 as F).0: K);      // scope 1 at $DIR/issue-41888.rs:10:21: 10:23
-        _0 = const ();                   // scope 1 at $DIR/issue-41888.rs:10:29: 13:10
+        StorageLive(_6);                 // scope 2 at $DIR/issue-41888.rs:10:21: 10:23
+        _9 = const false;                // scope 2 at $DIR/issue-41888.rs:10:21: 10:23
+        _6 = move ((_1 as F).0: K);      // scope 2 at $DIR/issue-41888.rs:10:21: 10:23
+        _0 = const ();                   // scope 2 at $DIR/issue-41888.rs:10:29: 13:10
         StorageDead(_6);                 // scope 1 at $DIR/issue-41888.rs:13:9: 13:10
         goto -> bb8;                     // scope 1 at $DIR/issue-41888.rs:10:9: 13:10
     }
diff --git a/src/test/mir-opt/issues/issue_75439.foo.MatchBranchSimplification.diff b/src/test/mir-opt/issues/issue_75439.foo.MatchBranchSimplification.diff
index 299529ec649..b8023a6a8e6 100644
--- a/src/test/mir-opt/issues/issue_75439.foo.MatchBranchSimplification.diff
+++ b/src/test/mir-opt/issues/issue_75439.foo.MatchBranchSimplification.diff
@@ -10,11 +10,11 @@
       let mut _6: u32;                     // in scope 0 at $DIR/issue-75439.rs:10:33: 10:35
       scope 1 {
           debug dwords => _2;              // in scope 1 at $DIR/issue-75439.rs:7:9: 7:15
-          let _4: u32;                     // in scope 1 at $DIR/issue-75439.rs:9:27: 9:29
           scope 3 {
               debug ip => _4;              // in scope 3 at $DIR/issue-75439.rs:9:27: 9:29
-          }
-          scope 4 {
+              let _4: u32;                 // in scope 3 at $DIR/issue-75439.rs:9:27: 9:29
+              scope 4 {
+              }
           }
       }
       scope 2 {
@@ -32,19 +32,19 @@
   
       bb1: {
           StorageDead(_3);                 // scope 2 at $DIR/issue-75439.rs:7:52: 7:53
-          switchInt(_2[0 of 4]) -> [0_u32: bb2, otherwise: bb8]; // scope 1 at $DIR/issue-75439.rs:9:12: 9:30
+          switchInt(_2[0 of 4]) -> [0_u32: bb2, otherwise: bb8]; // scope 3 at $DIR/issue-75439.rs:9:12: 9:30
       }
   
       bb2: {
-          switchInt(_2[1 of 4]) -> [0_u32: bb3, otherwise: bb8]; // scope 1 at $DIR/issue-75439.rs:9:12: 9:30
+          switchInt(_2[1 of 4]) -> [0_u32: bb3, otherwise: bb8]; // scope 3 at $DIR/issue-75439.rs:9:12: 9:30
       }
   
       bb3: {
-          switchInt(_2[2 of 4]) -> [0_u32: bb5, 4294901760_u32: bb6, otherwise: bb8]; // scope 1 at $DIR/issue-75439.rs:9:12: 9:30
+          switchInt(_2[2 of 4]) -> [0_u32: bb5, 4294901760_u32: bb6, otherwise: bb8]; // scope 3 at $DIR/issue-75439.rs:9:12: 9:30
       }
   
       bb4: {
-          StorageLive(_5);                 // scope 1 at $DIR/issue-75439.rs:10:14: 10:38
+          StorageLive(_5);                 // scope 3 at $DIR/issue-75439.rs:10:14: 10:38
           StorageLive(_6);                 // scope 4 at $DIR/issue-75439.rs:10:33: 10:35
           _6 = _4;                         // scope 4 at $DIR/issue-75439.rs:10:33: 10:35
           _5 = transmute::<u32, [u8; 4]>(move _6) -> bb7; // scope 4 at $DIR/issue-75439.rs:10:23: 10:36
@@ -54,23 +54,23 @@
       }
   
       bb5: {
-          StorageLive(_4);                 // scope 1 at $DIR/issue-75439.rs:9:27: 9:29
-          _4 = _2[3 of 4];                 // scope 1 at $DIR/issue-75439.rs:9:27: 9:29
-          goto -> bb4;                     // scope 1 at $DIR/issue-75439.rs:9:12: 9:30
+          StorageLive(_4);                 // scope 3 at $DIR/issue-75439.rs:9:27: 9:29
+          _4 = _2[3 of 4];                 // scope 3 at $DIR/issue-75439.rs:9:27: 9:29
+          goto -> bb4;                     // scope 3 at $DIR/issue-75439.rs:9:12: 9:30
       }
   
       bb6: {
-          StorageLive(_4);                 // scope 1 at $DIR/issue-75439.rs:9:27: 9:29
-          _4 = _2[3 of 4];                 // scope 1 at $DIR/issue-75439.rs:9:27: 9:29
-          goto -> bb4;                     // scope 1 at $DIR/issue-75439.rs:9:12: 9:30
+          StorageLive(_4);                 // scope 3 at $DIR/issue-75439.rs:9:27: 9:29
+          _4 = _2[3 of 4];                 // scope 3 at $DIR/issue-75439.rs:9:27: 9:29
+          goto -> bb4;                     // scope 3 at $DIR/issue-75439.rs:9:12: 9:30
       }
   
       bb7: {
           StorageDead(_6);                 // scope 4 at $DIR/issue-75439.rs:10:35: 10:36
-          Deinit(_0);                      // scope 1 at $DIR/issue-75439.rs:10:9: 10:39
-          ((_0 as Some).0: [u8; 4]) = move _5; // scope 1 at $DIR/issue-75439.rs:10:9: 10:39
-          discriminant(_0) = 1;            // scope 1 at $DIR/issue-75439.rs:10:9: 10:39
-          StorageDead(_5);                 // scope 1 at $DIR/issue-75439.rs:10:38: 10:39
+          Deinit(_0);                      // scope 3 at $DIR/issue-75439.rs:10:9: 10:39
+          ((_0 as Some).0: [u8; 4]) = move _5; // scope 3 at $DIR/issue-75439.rs:10:9: 10:39
+          discriminant(_0) = 1;            // scope 3 at $DIR/issue-75439.rs:10:9: 10:39
+          StorageDead(_5);                 // scope 3 at $DIR/issue-75439.rs:10:38: 10:39
           StorageDead(_4);                 // scope 1 at $DIR/issue-75439.rs:11:5: 11:6
           goto -> bb9;                     // scope 1 at $DIR/issue-75439.rs:9:5: 13:6
       }
diff --git a/src/test/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals.diff b/src/test/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals.diff
index a8cc61f0526..075fe8d0908 100644
--- a/src/test/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals.diff
+++ b/src/test/mir-opt/simplify_locals_fixedpoint.foo.SimplifyLocals.diff
@@ -8,44 +8,44 @@
       let mut _3: std::option::Option<T>;  // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
       let mut _4: isize;                   // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:22: 4:26
       let mut _5: isize;                   // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:13: 4:20
-      let _6: u8;                          // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
 -     let mut _7: bool;                    // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:20
 -     let mut _8: u8;                      // in scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:13
       scope 1 {
           debug a => _6;                   // in scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
+          let _6: u8;                      // in scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
       }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
-          StorageLive(_2);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
-          Deinit(_2);                      // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
-          discriminant(_2) = 0;            // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
-          StorageLive(_3);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
-          Deinit(_3);                      // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
-          discriminant(_3) = 0;            // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
-          Deinit(_1);                      // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
-          (_1.0: std::option::Option<u8>) = move _2; // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
-          (_1.1: std::option::Option<T>) = move _3; // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
-          StorageDead(_3);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:68: 4:69
-          StorageDead(_2);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:68: 4:69
-          _5 = discriminant((_1.0: std::option::Option<u8>)); // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
-          switchInt(move _5) -> [1_isize: bb1, otherwise: bb3]; // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
+          StorageLive(_1);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
+          StorageLive(_2);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
+          Deinit(_2);                      // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
+          discriminant(_2) = 0;            // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:31: 4:49
+          StorageLive(_3);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
+          Deinit(_3);                      // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
+          discriminant(_3) = 0;            // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:51: 4:68
+          Deinit(_1);                      // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
+          (_1.0: std::option::Option<u8>) = move _2; // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
+          (_1.1: std::option::Option<T>) = move _3; // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:30: 4:69
+          StorageDead(_3);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:68: 4:69
+          StorageDead(_2);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:68: 4:69
+          _5 = discriminant((_1.0: std::option::Option<u8>)); // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
+          switchInt(move _5) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
       }
   
       bb1: {
-          _4 = discriminant((_1.1: std::option::Option<T>)); // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
-          switchInt(move _4) -> [0_isize: bb2, otherwise: bb3]; // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
+          _4 = discriminant((_1.1: std::option::Option<T>)); // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
+          switchInt(move _4) -> [0_isize: bb2, otherwise: bb3]; // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:12: 4:27
       }
   
       bb2: {
-          StorageLive(_6);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
-          _6 = (((_1.0: std::option::Option<u8>) as Some).0: u8); // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
--         StorageLive(_7);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:20
--         StorageLive(_8);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:13
--         _8 = _6;                         // scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:13
--         _7 = Gt(move _8, const 42_u8);   // scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:20
--         StorageDead(_8);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:5:19: 5:20
--         StorageDead(_7);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:7:9: 7:10
+          StorageLive(_6);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
+          _6 = (((_1.0: std::option::Option<u8>) as Some).0: u8); // scope 1 at $DIR/simplify-locals-fixedpoint.rs:4:18: 4:19
+-         StorageLive(_7);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:20
+-         StorageLive(_8);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:13
+-         _8 = _6;                         // scope 1 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:13
+-         _7 = Gt(move _8, const 42_u8);   // scope 1 at $DIR/simplify-locals-fixedpoint.rs:5:12: 5:20
+-         StorageDead(_8);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:5:19: 5:20
+-         StorageDead(_7);                 // scope 1 at $DIR/simplify-locals-fixedpoint.rs:7:9: 7:10
           StorageDead(_6);                 // scope 0 at $DIR/simplify-locals-fixedpoint.rs:8:5: 8:6
           goto -> bb3;                     // scope 0 at $DIR/simplify-locals-fixedpoint.rs:4:5: 8:6
       }
diff --git a/src/test/mir-opt/unreachable.main.UnreachablePropagation.diff b/src/test/mir-opt/unreachable.main.UnreachablePropagation.diff
index 08312bde20f..70486f546d7 100644
--- a/src/test/mir-opt/unreachable.main.UnreachablePropagation.diff
+++ b/src/test/mir-opt/unreachable.main.UnreachablePropagation.diff
@@ -5,36 +5,36 @@
       let mut _0: ();                      // return place in scope 0 at $DIR/unreachable.rs:8:11: 8:11
       let mut _1: std::option::Option<Empty>; // in scope 0 at $DIR/unreachable.rs:9:23: 9:30
       let mut _2: isize;                   // in scope 0 at $DIR/unreachable.rs:9:12: 9:20
-      let _3: Empty;                       // in scope 0 at $DIR/unreachable.rs:9:17: 9:19
-      let mut _4: i32;                     // in scope 0 at $DIR/unreachable.rs:10:13: 10:19
       let _5: ();                          // in scope 0 at $DIR/unreachable.rs:12:9: 16:10
       let mut _6: bool;                    // in scope 0 at $DIR/unreachable.rs:12:12: 12:16
       let mut _7: !;                       // in scope 0 at $DIR/unreachable.rs:18:9: 18:21
       scope 1 {
           debug _x => _3;                  // in scope 1 at $DIR/unreachable.rs:9:17: 9:19
-      }
-      scope 2 {
-          debug _y => _4;                  // in scope 2 at $DIR/unreachable.rs:10:13: 10:19
+          let _3: Empty;                   // in scope 1 at $DIR/unreachable.rs:9:17: 9:19
+          let mut _4: i32;                 // in scope 1 at $DIR/unreachable.rs:10:13: 10:19
+          scope 2 {
+              debug _y => _4;              // in scope 2 at $DIR/unreachable.rs:10:13: 10:19
+          }
       }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/unreachable.rs:9:23: 9:30
-          _1 = empty() -> bb1;             // scope 0 at $DIR/unreachable.rs:9:23: 9:30
+          StorageLive(_1);                 // scope 1 at $DIR/unreachable.rs:9:23: 9:30
+          _1 = empty() -> bb1;             // scope 1 at $DIR/unreachable.rs:9:23: 9:30
                                            // mir::Constant
                                            // + span: $DIR/unreachable.rs:9:23: 9:28
                                            // + literal: Const { ty: fn() -> Option<Empty> {empty}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
-          _2 = discriminant(_1);           // scope 0 at $DIR/unreachable.rs:9:12: 9:20
--         switchInt(move _2) -> [1_isize: bb2, otherwise: bb6]; // scope 0 at $DIR/unreachable.rs:9:12: 9:20
-+         goto -> bb2;                     // scope 0 at $DIR/unreachable.rs:9:12: 9:20
+          _2 = discriminant(_1);           // scope 1 at $DIR/unreachable.rs:9:12: 9:20
+-         switchInt(move _2) -> [1_isize: bb2, otherwise: bb6]; // scope 1 at $DIR/unreachable.rs:9:12: 9:20
++         goto -> bb2;                     // scope 1 at $DIR/unreachable.rs:9:12: 9:20
       }
   
       bb2: {
--         StorageLive(_3);                 // scope 0 at $DIR/unreachable.rs:9:17: 9:19
--         _3 = move ((_1 as Some).0: Empty); // scope 0 at $DIR/unreachable.rs:9:17: 9:19
--         StorageLive(_4);                 // scope 0 at $DIR/unreachable.rs:10:13: 10:19
+-         StorageLive(_3);                 // scope 1 at $DIR/unreachable.rs:9:17: 9:19
+-         _3 = move ((_1 as Some).0: Empty); // scope 1 at $DIR/unreachable.rs:9:17: 9:19
+-         StorageLive(_4);                 // scope 1 at $DIR/unreachable.rs:10:13: 10:19
 -         StorageLive(_5);                 // scope 2 at $DIR/unreachable.rs:12:9: 16:10
 -         StorageLive(_6);                 // scope 2 at $DIR/unreachable.rs:12:12: 12:16
 -         _6 = const true;                 // scope 2 at $DIR/unreachable.rs:12:12: 12:16
diff --git a/src/test/mir-opt/unreachable_diverging.main.UnreachablePropagation.diff b/src/test/mir-opt/unreachable_diverging.main.UnreachablePropagation.diff
index e5867ccfc5c..d9f2681d145 100644
--- a/src/test/mir-opt/unreachable_diverging.main.UnreachablePropagation.diff
+++ b/src/test/mir-opt/unreachable_diverging.main.UnreachablePropagation.diff
@@ -11,56 +11,56 @@
       let mut _7: !;                       // in scope 0 at $DIR/unreachable_diverging.rs:18:9: 18:22
       scope 1 {
           debug x => _1;                   // in scope 1 at $DIR/unreachable_diverging.rs:13:9: 13:10
-          let _4: Empty;                   // in scope 1 at $DIR/unreachable_diverging.rs:14:17: 14:21
           scope 2 {
               debug bomb => _4;            // in scope 2 at $DIR/unreachable_diverging.rs:14:17: 14:21
+              let _4: Empty;               // in scope 2 at $DIR/unreachable_diverging.rs:14:17: 14:21
           }
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/unreachable_diverging.rs:13:9: 13:10
           _1 = const true;                 // scope 0 at $DIR/unreachable_diverging.rs:13:13: 13:17
-          StorageLive(_2);                 // scope 1 at $DIR/unreachable_diverging.rs:14:25: 14:32
-          _2 = empty() -> bb1;             // scope 1 at $DIR/unreachable_diverging.rs:14:25: 14:32
+          StorageLive(_2);                 // scope 2 at $DIR/unreachable_diverging.rs:14:25: 14:32
+          _2 = empty() -> bb1;             // scope 2 at $DIR/unreachable_diverging.rs:14:25: 14:32
                                            // mir::Constant
                                            // + span: $DIR/unreachable_diverging.rs:14:25: 14:30
                                            // + literal: Const { ty: fn() -> Option<Empty> {empty}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
-          _3 = discriminant(_2);           // scope 1 at $DIR/unreachable_diverging.rs:14:12: 14:22
--         switchInt(move _3) -> [1_isize: bb2, otherwise: bb6]; // scope 1 at $DIR/unreachable_diverging.rs:14:12: 14:22
-+         switchInt(move _3) -> [1_isize: bb2, otherwise: bb5]; // scope 1 at $DIR/unreachable_diverging.rs:14:12: 14:22
+          _3 = discriminant(_2);           // scope 2 at $DIR/unreachable_diverging.rs:14:12: 14:22
+-         switchInt(move _3) -> [1_isize: bb2, otherwise: bb6]; // scope 2 at $DIR/unreachable_diverging.rs:14:12: 14:22
++         switchInt(move _3) -> [1_isize: bb2, otherwise: bb5]; // scope 2 at $DIR/unreachable_diverging.rs:14:12: 14:22
       }
   
       bb2: {
-          StorageLive(_4);                 // scope 1 at $DIR/unreachable_diverging.rs:14:17: 14:21
-          _4 = move ((_2 as Some).0: Empty); // scope 1 at $DIR/unreachable_diverging.rs:14:17: 14:21
-          StorageLive(_5);                 // scope 1 at $DIR/unreachable_diverging.rs:15:9: 17:10
-          StorageLive(_6);                 // scope 1 at $DIR/unreachable_diverging.rs:15:12: 15:13
-          _6 = _1;                         // scope 1 at $DIR/unreachable_diverging.rs:15:12: 15:13
--         switchInt(move _6) -> [false: bb4, otherwise: bb3]; // scope 1 at $DIR/unreachable_diverging.rs:15:12: 15:13
-+         goto -> bb3;                     // scope 1 at $DIR/unreachable_diverging.rs:15:12: 15:13
+          StorageLive(_4);                 // scope 2 at $DIR/unreachable_diverging.rs:14:17: 14:21
+          _4 = move ((_2 as Some).0: Empty); // scope 2 at $DIR/unreachable_diverging.rs:14:17: 14:21
+          StorageLive(_5);                 // scope 2 at $DIR/unreachable_diverging.rs:15:9: 17:10
+          StorageLive(_6);                 // scope 2 at $DIR/unreachable_diverging.rs:15:12: 15:13
+          _6 = _1;                         // scope 2 at $DIR/unreachable_diverging.rs:15:12: 15:13
+-         switchInt(move _6) -> [false: bb4, otherwise: bb3]; // scope 2 at $DIR/unreachable_diverging.rs:15:12: 15:13
++         goto -> bb3;                     // scope 2 at $DIR/unreachable_diverging.rs:15:12: 15:13
       }
   
       bb3: {
--         _5 = loop_forever() -> bb5;      // scope 1 at $DIR/unreachable_diverging.rs:16:13: 16:27
-+         _5 = loop_forever() -> bb4;      // scope 1 at $DIR/unreachable_diverging.rs:16:13: 16:27
+-         _5 = loop_forever() -> bb5;      // scope 2 at $DIR/unreachable_diverging.rs:16:13: 16:27
++         _5 = loop_forever() -> bb4;      // scope 2 at $DIR/unreachable_diverging.rs:16:13: 16:27
                                            // mir::Constant
                                            // + span: $DIR/unreachable_diverging.rs:16:13: 16:25
                                            // + literal: Const { ty: fn() {loop_forever}, val: Value(Scalar(<ZST>)) }
       }
   
       bb4: {
--         _5 = const ();                   // scope 1 at $DIR/unreachable_diverging.rs:17:10: 17:10
--         goto -> bb5;                     // scope 1 at $DIR/unreachable_diverging.rs:15:9: 17:10
+-         _5 = const ();                   // scope 2 at $DIR/unreachable_diverging.rs:17:10: 17:10
+-         goto -> bb5;                     // scope 2 at $DIR/unreachable_diverging.rs:15:9: 17:10
 -     }
 - 
 -     bb5: {
-          StorageDead(_6);                 // scope 1 at $DIR/unreachable_diverging.rs:17:9: 17:10
-          StorageDead(_5);                 // scope 1 at $DIR/unreachable_diverging.rs:17:9: 17:10
-          StorageLive(_7);                 // scope 1 at $DIR/unreachable_diverging.rs:18:9: 18:22
-          unreachable;                     // scope 1 at $DIR/unreachable_diverging.rs:18:15: 18:19
+          StorageDead(_6);                 // scope 2 at $DIR/unreachable_diverging.rs:17:9: 17:10
+          StorageDead(_5);                 // scope 2 at $DIR/unreachable_diverging.rs:17:9: 17:10
+          StorageLive(_7);                 // scope 2 at $DIR/unreachable_diverging.rs:18:9: 18:22
+          unreachable;                     // scope 2 at $DIR/unreachable_diverging.rs:18:15: 18:19
       }
   
 -     bb6: {
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff
index 0529b15522e..f8b41d7b4c5 100644
--- a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff
+++ b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.32bit.diff
@@ -13,28 +13,30 @@
       let mut _8: !;                       // in scope 0 at $DIR/while_let_loops.rs:7:5: 10:6
       scope 1 {
           debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:6:9: 6:15
+          scope 2 {
+          }
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
           _1 = const 0_i32;                // scope 0 at $DIR/while_let_loops.rs:6:18: 6:19
-          StorageLive(_3);                 // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
-          Deinit(_3);                      // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
-          discriminant(_3) = 0;            // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
--         _4 = discriminant(_3);           // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
--         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
-+         _4 = const 0_isize;              // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
-+         switchInt(const 0_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
+          StorageLive(_3);                 // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+          Deinit(_3);                      // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+          discriminant(_3) = 0;            // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+-         _4 = discriminant(_3);           // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
+-         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
++         _4 = const 0_isize;              // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
++         switchInt(const 0_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
       }
   
       bb1: {
-          switchInt(((_3 as Some).0: u32)) -> [0_u32: bb2, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
+          switchInt(((_3 as Some).0: u32)) -> [0_u32: bb2, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
       }
   
       bb2: {
-          _1 = const 1_i32;                // scope 1 at $DIR/while_let_loops.rs:8:9: 8:15
-          nop;                             // scope 1 at $DIR/while_let_loops.rs:9:9: 9:14
-          goto -> bb4;                     // scope 1 at $DIR/while_let_loops.rs:9:9: 9:14
+          _1 = const 1_i32;                // scope 2 at $DIR/while_let_loops.rs:8:9: 8:15
+          nop;                             // scope 2 at $DIR/while_let_loops.rs:9:9: 9:14
+          goto -> bb4;                     // scope 2 at $DIR/while_let_loops.rs:9:9: 9:14
       }
   
       bb3: {
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff
index 0529b15522e..f8b41d7b4c5 100644
--- a/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff
+++ b/src/test/mir-opt/while_let_loops.change_loop_body.ConstProp.64bit.diff
@@ -13,28 +13,30 @@
       let mut _8: !;                       // in scope 0 at $DIR/while_let_loops.rs:7:5: 10:6
       scope 1 {
           debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:6:9: 6:15
+          scope 2 {
+          }
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
           _1 = const 0_i32;                // scope 0 at $DIR/while_let_loops.rs:6:18: 6:19
-          StorageLive(_3);                 // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
-          Deinit(_3);                      // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
-          discriminant(_3) = 0;            // scope 1 at $DIR/while_let_loops.rs:7:28: 7:32
--         _4 = discriminant(_3);           // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
--         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
-+         _4 = const 0_isize;              // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
-+         switchInt(const 0_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
+          StorageLive(_3);                 // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+          Deinit(_3);                      // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+          discriminant(_3) = 0;            // scope 2 at $DIR/while_let_loops.rs:7:28: 7:32
+-         _4 = discriminant(_3);           // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
+-         switchInt(move _4) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
++         _4 = const 0_isize;              // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
++         switchInt(const 0_isize) -> [1_isize: bb1, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
       }
   
       bb1: {
-          switchInt(((_3 as Some).0: u32)) -> [0_u32: bb2, otherwise: bb3]; // scope 1 at $DIR/while_let_loops.rs:7:15: 7:25
+          switchInt(((_3 as Some).0: u32)) -> [0_u32: bb2, otherwise: bb3]; // scope 2 at $DIR/while_let_loops.rs:7:15: 7:25
       }
   
       bb2: {
-          _1 = const 1_i32;                // scope 1 at $DIR/while_let_loops.rs:8:9: 8:15
-          nop;                             // scope 1 at $DIR/while_let_loops.rs:9:9: 9:14
-          goto -> bb4;                     // scope 1 at $DIR/while_let_loops.rs:9:9: 9:14
+          _1 = const 1_i32;                // scope 2 at $DIR/while_let_loops.rs:8:9: 8:15
+          nop;                             // scope 2 at $DIR/while_let_loops.rs:9:9: 9:14
+          goto -> bb4;                     // scope 2 at $DIR/while_let_loops.rs:9:9: 9:14
       }
   
       bb3: {
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir
index 3c94fbddc44..5657f9413a1 100644
--- a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir
+++ b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir
@@ -5,6 +5,8 @@ fn change_loop_body() -> () {
     let mut _1: i32;                     // in scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
     scope 1 {
         debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:6:9: 6:15
+        scope 2 {
+        }
     }
 
     bb0: {
diff --git a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir
index 3c94fbddc44..5657f9413a1 100644
--- a/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir
+++ b/src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir
@@ -5,6 +5,8 @@ fn change_loop_body() -> () {
     let mut _1: i32;                     // in scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
     scope 1 {
         debug _x => _1;                  // in scope 1 at $DIR/while_let_loops.rs:6:9: 6:15
+        scope 2 {
+        }
     }
 
     bb0: {