Auto merge of #103957 - JakobDegen:drop-retag, r=RalfJung

Retag as FnEntry on `drop_in_place`

This commit changes the mir drop shim to always retag its argument as if it were a `&mut`.

cc rust-lang/unsafe-code-guidelines#373

1 files changed, 5 insertions, 2 deletions

diff --git a/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir b/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
index 14f297e948b..f495f147be3 100644
--- a/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
+++ b/src/test/mir-opt/retag.core.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
@@ -3,11 +3,14 @@
 fn std::ptr::drop_in_place(_1: *mut Test) -> () {
     let mut _0: ();                      // return place in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
     let mut _2: &mut Test;               // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-    let mut _3: ();                      // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
+    let mut _3: &mut Test;               // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
+    let mut _4: ();                      // in scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
 
     bb0: {
         _2 = &mut (*_1);                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
-        _3 = <Test as Drop>::drop(move _2) -> bb1; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
+        Retag([fn entry] _2);            // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
+        _3 = &mut (*_2);                 // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
+        _4 = <Test as Drop>::drop(move _3) -> bb1; // scope 0 at $SRC_DIR/core/src/ptr/mod.rs:+0:1: +0:56
                                          // mir::Constant
                                          // + span: $SRC_DIR/core/src/ptr/mod.rs:LL:COL
                                          // + literal: Const { ty: for<'a> fn(&'a mut Test) {<Test as Drop>::drop}, val: Value(<ZST>) }