Auto merge of rust-lang#132356 - jieyouxu:unsound-simplify_aggregate_to_copy, r=cjgillot,DianQK

bors · bors · commit 99b0f2109fa6 · 2024-10-31T09:14:45.000Z
Mark `simplify_aggregate_to_copy` mir-opt as unsound Mark the `simplify_aggregate_to_copy` mir-opt added in rust-lang#128299 as unsound as it seems to miscompile the MCVE reported in rust-lang#132353. The mir-opt can be re-enabled once this case is fixed. ```rs fn pop_min(mut score2head: Vec<Option<usize>>) -> Option<usize> { loop { if let Some(col) = score2head[0] { score2head[0] = None; return Some(col); } } } fn main() { let min = pop_min(vec![Some(1)]); println!("min: {:?}", min); // panic happens here on beta in release mode // but not in debug mode min.unwrap(); } ``` This MCVE is included as a `run-pass` ui regression test in the first commit. I built the ui test with a nightly manually, and can reproduce the behavioral difference with `-C opt-level=0` and `-C opt-level=1`. Locally, this ui test will fail unless it was run on a compiler built with the second commit marking the mir-opt as unsound thus disabling it by default. This PR **partially reverts** commit e7386b3, reversing changes made to 02b1be1. The mir-opt implementation is just marked as unsound but **not** reverted to make reland reviews easier. The test changes are **fully** reverted. cc `@DianQK` `@cjgillot` (PR author and reviewer of rust-lang#128299)
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs
@@ -1082,7 +1082,9 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {
             }
         }
 
-        if let AggregateTy::Def(_, _) = ty
+        // unsound: https://github.com/rust-lang/rust/issues/132353
+        if tcx.sess.opts.unstable_opts.unsound_mir_opts
+            && let AggregateTy::Def(_, _) = ty
             && let Some(value) =
                 self.simplify_aggregate_to_copy(rvalue, location, &fields, variant_index)
         {
diff --git a/tests/codegen/clone_as_copy.rs b/tests/codegen/clone_as_copy.rs
@@ -1,4 +1,6 @@
 //@ revisions: DEBUGINFO NODEBUGINFO
+//@ compile-flags: -Zunsound-mir-opts
+// FIXME: see <https://github.com/rust-lang/rust/issues/132353>
 //@ compile-flags: -O -Cno-prepopulate-passes
 //@ [DEBUGINFO] compile-flags: -Cdebuginfo=full
 
diff --git a/tests/codegen/try_question_mark_nop.rs b/tests/codegen/try_question_mark_nop.rs
@@ -1,10 +1,7 @@
 //@ compile-flags: -O -Z merge-functions=disabled --edition=2021
 //@ only-x86_64
 // FIXME: Remove the `min-llvm-version`.
-//@ revisions: NINETEEN TWENTY
-//@[NINETEEN] min-llvm-version: 19
-//@[NINETEEN] ignore-llvm-version: 20-99
-//@[TWENTY] min-llvm-version: 20
+//@ min-llvm-version: 19
 
 #![crate_type = "lib"]
 #![feature(try_blocks)]
@@ -16,12 +13,9 @@ use std::ptr::NonNull;
 #[no_mangle]
 pub fn option_nop_match_32(x: Option<u32>) -> Option<u32> {
     // CHECK: start:
-    // NINETEEN-NEXT: [[TRUNC:%.*]] = trunc nuw i32 %0 to i1
-    // NINETEEN-NEXT: [[FIRST:%.*]] = select i1 [[TRUNC]], i32 %0
-    // NINETEEN-NEXT: insertvalue { i32, i32 } poison, i32 [[FIRST]], 0
-    // TWENTY-NEXT: insertvalue { i32, i32 } poison, i32 %0, 0
-    // CHECK-NEXT: insertvalue { i32, i32 }
-    // CHECK-NEXT: ret { i32, i32 }
+    // CHECK-NEXT: [[REG1:%.*]] = insertvalue { i32, i32 } poison, i32 %0, 0
+    // CHECK-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } [[REG1]], i32 %1, 1
+    // CHECK-NEXT: ret { i32, i32 } [[REG2]]
     match x {
         Some(x) => Some(x),
         None => None,
diff --git a/tests/mir-opt/gvn_clone.rs b/tests/mir-opt/gvn_clone.rs
@@ -1,3 +1,5 @@
+//@ compile-flags: -Zunsound-mir-opts
+// FIXME: see <https://github.com/rust-lang/rust/issues/132353>
 //@ test-mir-pass: GVN
 //@ compile-flags: -Zmir-enable-passes=+InstSimplify-before-inline
 
diff --git a/tests/mir-opt/gvn_clone.{impl#0}-clone.GVN.diff b/tests/mir-opt/gvn_clone.{impl#0}-clone.GVN.diff
@@ -1,7 +1,7 @@
-- // MIR for `<impl at $DIR/gvn_clone.rs:12:10: 12:15>::clone` before GVN
-+ // MIR for `<impl at $DIR/gvn_clone.rs:12:10: 12:15>::clone` after GVN
+- // MIR for `<impl at $DIR/gvn_clone.rs:14:10: 14:15>::clone` before GVN
++ // MIR for `<impl at $DIR/gvn_clone.rs:14:10: 14:15>::clone` after GVN
   
-  fn <impl at $DIR/gvn_clone.rs:12:10: 12:15>::clone(_1: &AllCopy) -> AllCopy {
+  fn <impl at $DIR/gvn_clone.rs:14:10: 14:15>::clone(_1: &AllCopy) -> AllCopy {
       debug self => _1;
       let mut _0: AllCopy;
       let mut _2: i32;
diff --git a/tests/mir-opt/gvn_copy_aggregate.rs b/tests/mir-opt/gvn_copy_aggregate.rs
@@ -1,3 +1,5 @@
+//@ compile-flags: -Zunsound-mir-opts
+// FIXME: see <https://github.com/rust-lang/rust/issues/132353.
 //@ test-mir-pass: GVN
 //@ compile-flags: -Cpanic=abort
 
diff --git a/tests/mir-opt/pre-codegen/clone_as_copy.rs b/tests/mir-opt/pre-codegen/clone_as_copy.rs
@@ -1,3 +1,5 @@
+//@ compile-flags: -Zunsound-mir-opts
+// FIXME: see <https://github.com/rust-lang/rust/issues/132353>
 //@ compile-flags: -Cdebuginfo=full
 
 // Check if we have transformed the nested clone to the copy in the complete pipeline.
diff --git a/tests/mir-opt/pre-codegen/no_inlined_clone.{impl#0}-clone.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/no_inlined_clone.{impl#0}-clone.PreCodegen.after.mir
@@ -3,9 +3,13 @@
 fn <impl at $DIR/no_inlined_clone.rs:9:10: 9:15>::clone(_1: &Foo) -> Foo {
     debug self => _1;
     let mut _0: Foo;
+    let mut _2: i32;
 
     bb0: {
-        _0 = copy (*_1);
+        StorageLive(_2);
+        _2 = copy ((*_1).0: i32);
+        _0 = Foo { a: move _2 };
+        StorageDead(_2);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/try_identity.old.PreCodegen.after.mir b/tests/mir-opt/pre-codegen/try_identity.old.PreCodegen.after.mir
@@ -19,14 +19,14 @@ fn old(_1: Result<T, E>) -> Result<T, E> {
     }
 
     bb1: {
-        _3 = copy ((_1 as Ok).0: T);
-        _0 = copy _1;
+        _3 = move ((_1 as Ok).0: T);
+        _0 = Result::<T, E>::Ok(copy _3);
         goto -> bb3;
     }
 
     bb2: {
-        _4 = copy ((_1 as Err).0: E);
-        _0 = copy _1;
+        _4 = move ((_1 as Err).0: E);
+        _0 = Result::<T, E>::Err(copy _4);
         goto -> bb3;
     }
 
diff --git a/tests/mir-opt/pre-codegen/vec_deref.vec_deref_to_slice.PreCodegen.after.panic-abort.mir b/tests/mir-opt/pre-codegen/vec_deref.vec_deref_to_slice.PreCodegen.after.panic-abort.mir
@@ -7,7 +7,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
         debug self => _1;
         scope 2 (inlined Vec::<u8>::as_slice) {
             debug self => _1;
-            let mut _6: usize;
+            let mut _7: usize;
             scope 3 (inlined Vec::<u8>::as_ptr) {
                 debug self => _1;
                 let mut _2: &alloc::raw_vec::RawVec<u8>;
@@ -16,6 +16,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                     let mut _3: &alloc::raw_vec::RawVecInner;
                     scope 5 (inlined alloc::raw_vec::RawVecInner::ptr::<u8>) {
                         debug self => _3;
+                        let mut _6: std::ptr::NonNull<u8>;
                         scope 6 (inlined alloc::raw_vec::RawVecInner::non_null::<u8>) {
                             debug self => _3;
                             let mut _4: std::ptr::NonNull<u8>;
@@ -31,20 +32,20 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                                 }
                             }
                             scope 10 (inlined Unique::<u8>::as_non_null_ptr) {
-                                debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _4;
+                                debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _6;
                                 debug ((self: Unique<u8>).1: std::marker::PhantomData<u8>) => const PhantomData::<u8>;
                             }
                         }
                         scope 11 (inlined NonNull::<u8>::as_ptr) {
-                            debug self => _4;
+                            debug self => _6;
                         }
                     }
                 }
             }
             scope 12 (inlined std::slice::from_raw_parts::<'_, u8>) {
                 debug data => _5;
-                debug len => _6;
-                let _7: *const [u8];
+                debug len => _7;
+                let _8: *const [u8];
                 scope 13 (inlined core::ub_checks::check_language_ub) {
                     scope 14 (inlined core::ub_checks::check_language_ub::runtime) {
                     }
@@ -55,10 +56,10 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                 }
                 scope 17 (inlined slice_from_raw_parts::<u8>) {
                     debug data => _5;
-                    debug len => _6;
+                    debug len => _7;
                     scope 18 (inlined std::ptr::from_raw_parts::<[u8], u8>) {
                         debug data_pointer => _5;
-                        debug metadata => _6;
+                        debug metadata => _7;
                     }
                 }
             }
@@ -70,17 +71,22 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
         _2 = &((*_1).0: alloc::raw_vec::RawVec<u8>);
         StorageLive(_3);
         _3 = &(((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner);
+        StorageLive(_6);
+        StorageLive(_4);
         _4 = copy (((((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);
         _5 = copy (_4.0: *const u8);
+        _6 = NonNull::<u8> { pointer: copy _5 };
+        StorageDead(_4);
+        StorageDead(_6);
         StorageDead(_3);
         StorageDead(_2);
-        StorageLive(_6);
-        _6 = copy ((*_1).1: usize);
         StorageLive(_7);
-        _7 = *const [u8] from (copy _5, copy _6);
-        _0 = &(*_7);
+        _7 = copy ((*_1).1: usize);
+        StorageLive(_8);
+        _8 = *const [u8] from (copy _5, copy _7);
+        _0 = &(*_8);
+        StorageDead(_8);
         StorageDead(_7);
-        StorageDead(_6);
         return;
     }
 }
diff --git a/tests/mir-opt/pre-codegen/vec_deref.vec_deref_to_slice.PreCodegen.after.panic-unwind.mir b/tests/mir-opt/pre-codegen/vec_deref.vec_deref_to_slice.PreCodegen.after.panic-unwind.mir
@@ -7,7 +7,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
         debug self => _1;
         scope 2 (inlined Vec::<u8>::as_slice) {
             debug self => _1;
-            let mut _6: usize;
+            let mut _7: usize;
             scope 3 (inlined Vec::<u8>::as_ptr) {
                 debug self => _1;
                 let mut _2: &alloc::raw_vec::RawVec<u8>;
@@ -16,6 +16,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                     let mut _3: &alloc::raw_vec::RawVecInner;
                     scope 5 (inlined alloc::raw_vec::RawVecInner::ptr::<u8>) {
                         debug self => _3;
+                        let mut _6: std::ptr::NonNull<u8>;
                         scope 6 (inlined alloc::raw_vec::RawVecInner::non_null::<u8>) {
                             debug self => _3;
                             let mut _4: std::ptr::NonNull<u8>;
@@ -31,20 +32,20 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                                 }
                             }
                             scope 10 (inlined Unique::<u8>::as_non_null_ptr) {
-                                debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _4;
+                                debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _6;
                                 debug ((self: Unique<u8>).1: std::marker::PhantomData<u8>) => const PhantomData::<u8>;
                             }
                         }
                         scope 11 (inlined NonNull::<u8>::as_ptr) {
-                            debug self => _4;
+                            debug self => _6;
                         }
                     }
                 }
             }
             scope 12 (inlined std::slice::from_raw_parts::<'_, u8>) {
                 debug data => _5;
-                debug len => _6;
-                let _7: *const [u8];
+                debug len => _7;
+                let _8: *const [u8];
                 scope 13 (inlined core::ub_checks::check_language_ub) {
                     scope 14 (inlined core::ub_checks::check_language_ub::runtime) {
                     }
@@ -55,10 +56,10 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
                 }
                 scope 17 (inlined slice_from_raw_parts::<u8>) {
                     debug data => _5;
-                    debug len => _6;
+                    debug len => _7;
                     scope 18 (inlined std::ptr::from_raw_parts::<[u8], u8>) {
                         debug data_pointer => _5;
-                        debug metadata => _6;
+                        debug metadata => _7;
                     }
                 }
             }
@@ -70,17 +71,22 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {
         _2 = &((*_1).0: alloc::raw_vec::RawVec<u8>);
         StorageLive(_3);
         _3 = &(((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner);
+        StorageLive(_6);
+        StorageLive(_4);
         _4 = copy (((((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);
         _5 = copy (_4.0: *const u8);
+        _6 = NonNull::<u8> { pointer: copy _5 };
+        StorageDead(_4);
+        StorageDead(_6);
         StorageDead(_3);
         StorageDead(_2);
-        StorageLive(_6);
-        _6 = copy ((*_1).1: usize);
         StorageLive(_7);
-        _7 = *const [u8] from (copy _5, copy _6);
-        _0 = &(*_7);
+        _7 = copy ((*_1).1: usize);
+        StorageLive(_8);
+        _8 = *const [u8] from (copy _5, copy _7);
+        _0 = &(*_8);
+        StorageDead(_8);
         StorageDead(_7);
-        StorageDead(_6);
         return;
     }
 }
diff --git a/tests/mir-opt/simplify_aggregate_to_copy_miscompile.foo.GVN.diff b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.foo.GVN.diff
@@ -0,0 +1,72 @@
+- // MIR for `foo` before GVN
++ // MIR for `foo` after GVN
+  
+  fn foo(_1: &mut Option<i32>) -> Option<i32> {
+      debug v => _1;
+      let mut _0: std::option::Option<i32>;
+      let mut _2: &std::option::Option<i32>;
+      let mut _3: &std::option::Option<i32>;
+      let _4: &&mut std::option::Option<i32>;
+      let mut _5: isize;
+      let mut _7: !;
+      let mut _8: std::option::Option<i32>;
+      let mut _9: i32;
+      let mut _10: !;
+      let mut _11: &mut std::option::Option<i32>;
+      scope 1 {
+          debug col => _6;
+          let _6: i32;
+      }
+  
+      bb0: {
+-         StorageLive(_2);
++         nop;
+          StorageLive(_3);
+          StorageLive(_4);
+          _4 = &_1;
+-         _11 = deref_copy (*_4);
+-         _3 = &(*_11);
++         _11 = copy _1;
++         _3 = &(*_1);
+          _2 = get(move _3) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          StorageDead(_3);
+          _5 = discriminant((*_2));
+          switchInt(move _5) -> [1: bb2, otherwise: bb3];
+      }
+  
+      bb2: {
+-         StorageLive(_6);
++         nop;
+          _6 = copy (((*_2) as Some).0: i32);
+          StorageLive(_8);
+-         _8 = Option::<i32>::None;
+-         (*_1) = move _8;
++         _8 = const Option::<i32>::None;
++         (*_1) = const Option::<i32>::None;
+          StorageDead(_8);
+          StorageLive(_9);
+          _9 = copy _6;
+-         _0 = Option::<i32>::Some(move _9);
++         _0 = copy (*_2);
+          StorageDead(_9);
+-         StorageDead(_6);
++         nop;
+          StorageDead(_4);
+-         StorageDead(_2);
++         nop;
+          return;
+      }
+  
+      bb3: {
+          StorageLive(_10);
+          unreachable;
+      }
++ }
++ 
++ ALLOC0 (size: 8, align: 4) {
++     00 00 00 00 __ __ __ __                         │ ....░░░░
+  }
+  
diff --git a/tests/mir-opt/simplify_aggregate_to_copy_miscompile.rs b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.rs
@@ -0,0 +1,32 @@
+//! The `simplify_aggregate_to_copy` mir-opt introduced in
+//! <https://github.com/rust-lang/rust/pull/128299> caused a miscompile because the initial
+//! implementation
+//!
+//! > introduce[d] new dereferences without checking for aliasing
+//!
+//! This test demonstrates the behavior, and should be adjusted or removed when fixing and relanding
+//! the mir-opt.
+#![crate_type = "lib"]
+// skip-filecheck
+//@ compile-flags: -O -Zunsound-mir-opts
+//@ test-mir-pass: GVN
+#![allow(internal_features)]
+#![feature(rustc_attrs, core_intrinsics)]
+
+// EMIT_MIR simplify_aggregate_to_copy_miscompile.foo.GVN.diff
+#[no_mangle]
+fn foo(v: &mut Option<i32>) -> Option<i32> {
+    if let &Some(col) = get(&v) {
+        *v = None;
+        return Some(col);
+    } else {
+        unsafe { std::intrinsics::unreachable() }
+    }
+}
+
+#[no_mangle]
+#[inline(never)]
+#[rustc_nounwind]
+fn get(v: &Option<i32>) -> &Option<i32> {
+    v
+}
diff --git a/tests/ui/mir/clone-canonicalization-miscompile-132353.rs b/tests/ui/mir/clone-canonicalization-miscompile-132353.rs

Original file line number	Diff line number	Diff line change
`@@ -1082,7 +1082,9 @@ impl<'body, 'tcx> VnState<'body, 'tcx> {`
`1082`	`1082`	`}`
`1083`	`1083`	`}`
`1084`	`1084`
`1085`		`- if let AggregateTy::Def(_, _) = ty`
	`1085`	`+ // unsound: https://github.com/rust-lang/rust/issues/132353`
	`1086`	`+ if tcx.sess.opts.unstable_opts.unsound_mir_opts`
	`1087`	`+ && let AggregateTy::Def(_, _) = ty`
`1086`	`1088`	`&& let Some(value) =`
`1087`	`1089`	`self.simplify_aggregate_to_copy(rvalue, location, &fields, variant_index)`
`1088`	`1090`	`{`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+//@ compile-flags: -Zunsound-mir-opts`
	`2`	`+// FIXME: see <https://github.com/rust-lang/rust/issues/132353>`
`1`	`3`	`//@ test-mir-pass: GVN`
`2`	`4`	`//@ compile-flags: -Zmir-enable-passes=+InstSimplify-before-inline`
`3`	`5`
Original file line number	Diff line number	Diff line change
`@@ -3,9 +3,13 @@`
`3`	`3`	`fn <impl at $DIR/no_inlined_clone.rs:9:10: 9:15>::clone(_1: &Foo) -> Foo {`
`4`	`4`	`debug self => _1;`
`5`	`5`	`let mut _0: Foo;`
	`6`	`+ let mut _2: i32;`
`6`	`7`
`7`	`8`	`bb0: {`
`8`		`- _0 = copy (*_1);`
	`9`	`+ StorageLive(_2);`
	`10`	`+ _2 = copy ((*_1).0: i32);`
	`11`	`+ _0 = Foo { a: move _2 };`
	`12`	`+ StorageDead(_2);`
`9`	`13`	`return;`
`10`	`14`	`}`
`11`	`15`	`}`
Original file line number	Diff line number	Diff line change
`@@ -19,14 +19,14 @@ fn old(_1: Result<T, E>) -> Result<T, E> {`
`19`	`19`	`}`
`20`	`20`
`21`	`21`	`bb1: {`
`22`		`- _3 = copy ((_1 as Ok).0: T);`
`23`		`- _0 = copy _1;`
	`22`	`+ _3 = move ((_1 as Ok).0: T);`
	`23`	`+ _0 = Result::<T, E>::Ok(copy _3);`
`24`	`24`	`goto -> bb3;`
`25`	`25`	`}`
`26`	`26`
`27`	`27`	`bb2: {`
`28`		`- _4 = copy ((_1 as Err).0: E);`
`29`		`- _0 = copy _1;`
	`28`	`+ _4 = move ((_1 as Err).0: E);`
	`29`	`+ _0 = Result::<T, E>::Err(copy _4);`
`30`	`30`	`goto -> bb3;`
`31`	`31`	`}`
`32`	`32`
Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {`
`7`	`7`	`debug self => _1;`
`8`	`8`	`scope 2 (inlined Vec::<u8>::as_slice) {`
`9`	`9`	`debug self => _1;`
`10`		`- let mut _6: usize;`
	`10`	`+ let mut _7: usize;`
`11`	`11`	`scope 3 (inlined Vec::<u8>::as_ptr) {`
`12`	`12`	`debug self => _1;`
`13`	`13`	`let mut _2: &alloc::raw_vec::RawVec<u8>;`
`@@ -16,6 +16,7 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {`
`16`	`16`	`let mut _3: &alloc::raw_vec::RawVecInner;`
`17`	`17`	`scope 5 (inlined alloc::raw_vec::RawVecInner::ptr::<u8>) {`
`18`	`18`	`debug self => _3;`
	`19`	`+ let mut _6: std::ptr::NonNull<u8>;`
`19`	`20`	`scope 6 (inlined alloc::raw_vec::RawVecInner::non_null::<u8>) {`
`20`	`21`	`debug self => _3;`
`21`	`22`	`let mut _4: std::ptr::NonNull<u8>;`
`@@ -31,20 +32,20 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {`
`31`	`32`	`}`
`32`	`33`	`}`
`33`	`34`	`scope 10 (inlined Unique::<u8>::as_non_null_ptr) {`
`34`		`- debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _4;`
	`35`	`+ debug ((self: Unique<u8>).0: std::ptr::NonNull<u8>) => _6;`
`35`	`36`	`debug ((self: Unique<u8>).1: std::marker::PhantomData<u8>) => const PhantomData::<u8>;`
`36`	`37`	`}`
`37`	`38`	`}`
`38`	`39`	`scope 11 (inlined NonNull::<u8>::as_ptr) {`
`39`		`- debug self => _4;`
	`40`	`+ debug self => _6;`
`40`	`41`	`}`
`41`	`42`	`}`
`42`	`43`	`}`
`43`	`44`	`}`
`44`	`45`	`scope 12 (inlined std::slice::from_raw_parts::<'_, u8>) {`
`45`	`46`	`debug data => _5;`
`46`		`- debug len => _6;`
`47`		`- let _7: *const [u8];`
	`47`	`+ debug len => _7;`
	`48`	`+ let _8: *const [u8];`
`48`	`49`	`scope 13 (inlined core::ub_checks::check_language_ub) {`
`49`	`50`	`scope 14 (inlined core::ub_checks::check_language_ub::runtime) {`
`50`	`51`	`}`
`@@ -55,10 +56,10 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {`
`55`	`56`	`}`
`56`	`57`	`scope 17 (inlined slice_from_raw_parts::<u8>) {`
`57`	`58`	`debug data => _5;`
`58`		`- debug len => _6;`
	`59`	`+ debug len => _7;`
`59`	`60`	`scope 18 (inlined std::ptr::from_raw_parts::<[u8], u8>) {`
`60`	`61`	`debug data_pointer => _5;`
`61`		`- debug metadata => _6;`
	`62`	`+ debug metadata => _7;`
`62`	`63`	`}`
`63`	`64`	`}`
`64`	`65`	`}`
`@@ -70,17 +71,22 @@ fn vec_deref_to_slice(_1: &Vec<u8>) -> &[u8] {`
`70`	`71`	`_2 = &((*_1).0: alloc::raw_vec::RawVec<u8>);`
`71`	`72`	`StorageLive(_3);`
`72`	`73`	`_3 = &(((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner);`
	`74`	`+ StorageLive(_6);`
	`75`	`+ StorageLive(_4);`
`73`	`76`	`_4 = copy (((((*_1).0: alloc::raw_vec::RawVec<u8>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);`
`74`	`77`	`_5 = copy (_4.0: *const u8);`
	`78`	`+ _6 = NonNull::<u8> { pointer: copy _5 };`
	`79`	`+ StorageDead(_4);`
	`80`	`+ StorageDead(_6);`
`75`	`81`	`StorageDead(_3);`
`76`	`82`	`StorageDead(_2);`
`77`		`- StorageLive(_6);`
`78`		`- _6 = copy ((*_1).1: usize);`
`79`	`83`	`StorageLive(_7);`
`80`		`- _7 = *const [u8] from (copy _5, copy _6);`
`81`		`- _0 = &(*_7);`
	`84`	`+ _7 = copy ((*_1).1: usize);`
	`85`	`+ StorageLive(_8);`
	`86`	`+ _8 = *const [u8] from (copy _5, copy _7);`
	`87`	`+ _0 = &(*_8);`
	`88`	`+ StorageDead(_8);`
`82`	`89`	`StorageDead(_7);`
`83`		`- StorageDead(_6);`
`84`	`90`	`return;`
`85`	`91`	`}`
`86`	`92`	`}`