fix tree borrows Unique test

Author: RalfJung

src/tools/miri/tests/pass/tree_borrows/vec_unique.rs

@@ -1,5 +1,3 @@
-// FIXME: This test is broken since https://github.com/rust-lang/rust/pull/126793,
-// possibly related to the additional struct between Vec and Unique.
 //@revisions: default uniq
 // We disable the GC for this test because it would change what is printed.
 //@compile-flags: -Zmiri-tree-borrows -Zmiri-provenance-gc=0
@@ -32,20 +30,20 @@ fn main() {
         // whether we got the distance correct:
         // If the output shows
         //
-        //    |- <XYZ: uniq>
-        //    '- <XYZ: uniq>
+        //    ├─ <TAG=base.as_ptr()>
+        //    └─ <TAG=base.as_ptr()>
         //
         // then `nth_parent` is not big enough.
         // The correct value for `nth_parent` should be the minimum
         // integer for which the output shows
         //
-        //    '- <XYZ: uniq, uniq>
+        //    └─ <TAG=base.as_ptr(), base.as_ptr(), ...>
         // )
         //
         // Ultimately we want pointers obtained through independent
         // calls of `as_ptr` to be able to alias, which will probably involve
         // a new permission that allows aliasing when there is no protector.
-        let nth_parent = if cfg!(uniq) { 2 } else { 0 };
+        let nth_parent = if cfg!(uniq) { 9 } else { 0 };
         name!(base.as_ptr()=>nth_parent);
         name!(base.as_ptr()=>nth_parent);
 

src/tools/miri/tests/pass/tree_borrows/vec_unique.uniq.stderr

@@ -2,9 +2,7 @@
 Warning: this tree is indicative only. Some tags may have been hidden.
 0..   2
 | Act |    └─┬──<TAG=root of the allocation>
-|-----|      ├────<TAG=base.as_ptr()>
-|-----|      ├────<TAG=base.as_ptr()>
-|-----|      └─┬──<TAG=raw_parts.0>
-|-----|        ├────<TAG=reconstructed.as_ptr()>
-|-----|        └────<TAG=reconstructed.as_ptr()>
+|-----|      └─┬──<TAG=base.as_ptr(), base.as_ptr()>
+|-----|        └─┬──<TAG=raw_parts.0>
+|-----|          └────<TAG=reconstructed.as_ptr(), reconstructed.as_ptr()>
 ──────────────────────────────────────────────────