Retag argument to drop_in_place unconditionally

Author: JakobDegen

tests/fail/stacked_borrows/drop_in_place_protector.rs

@@ -10,7 +10,7 @@ impl Drop for HasDrop {
     fn drop(&mut self) {
         unsafe {
             let _val = *P;
-            //~^ ERROR: /not granting access .* because that would remove .* which is protected/
+            //~^ ERROR: /not granting access .* because that would remove .* which is strongly protected/
         }
     }
 }

tests/fail/stacked_borrows/drop_in_place_protector.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+error: Undefined Behavior: not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is strongly protected because it is an argument of call ID
   --> $DIR/drop_in_place_protector.rs:LL:CC
    |
 LL |             let _val = *P;
-   |                        ^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is protected because it is an argument of call ID
+   |                        ^^ not granting access to tag <TAG> because that would remove [Unique for <TAG>] which is strongly protected because it is an argument of call ID
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information

tests/fail/stacked_borrows/drop_in_place_retag.rs

@@ -3,16 +3,9 @@
 
 //@error-pattern: /retag .* for Unique permission .* only grants SharedReadOnly permission/
 
-#[repr(transparent)]
-struct HasDrop;
-
-impl Drop for HasDrop {
-    fn drop(&mut self) {}
-}
-
 fn main() {
     unsafe {
-        let x = (0u8, HasDrop);
+        let x = 0u8;
         let x = core::ptr::addr_of!(x);
         core::ptr::drop_in_place(x.cast_mut());
     }

tests/fail/stacked_borrows/drop_in_place_retag.stderr

@@ -15,7 +15,7 @@ help: <TAG> was created by a SharedReadOnly retag at offsets [0x0..0x1]
 LL |         let x = core::ptr::addr_of!(x);
    |                 ^^^^^^^^^^^^^^^^^^^^^^
    = note: BACKTRACE:
-   = note: inside `std::ptr::drop_in_place::<(u8, HasDrop)> - shim(Some((u8, HasDrop)))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
+   = note: inside `std::ptr::drop_in_place::<u8> - shim(None)` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
 note: inside `main` at $DIR/drop_in_place_retag.rs:LL:CC
   --> $DIR/drop_in_place_retag.rs:LL:CC
    |