1 files changed, 22 insertions, 3 deletions
diff --git a/src/tools/miri/tests/fail/tree-borrows/read-to-local.stderr b/src/tools/miri/tests/fail/tree-borrows/read-to-local.stderr
index 7d9367c87d0..8c9c2f8f965 100644
--- a/src/tools/miri/tests/fail/tree-borrows/read-to-local.stderr
+++ b/src/tools/miri/tests/fail/tree-borrows/read-to-local.stderr
@@ -1,12 +1,31 @@
-error: Undefined Behavior: write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+error: Undefined Behavior: write access through <TAG> is forbidden
   --> $DIR/read-to-local.rs:LL:CC
    |
 LL |         *ptr = 0;
-   |         ^^^^^^^^ write access through <TAG> is forbidden because it is a child of <TAG> which is Frozen.
+   |         ^^^^^^^^ write access through <TAG> is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
-   = note: BACKTRACE:
+   = help: the accessed tag <TAG> has state Frozen which forbids child write accesses
+help: the accessed tag <TAG> was created here, in the initial state Reserved
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         let mref = &mut root;
+   |                    ^^^^^^^^^
+help: the accessed tag <TAG> then transitioned from Reserved to Active due to a child write access at offsets [0x0..0x1]
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         *ptr = 0; // Write
+   |         ^^^^^^^^
+   = help: this corresponds to an activation
+help: the accessed tag <TAG> then transitioned from Active to Frozen due to a foreign read access at offsets [0x0..0x1]
+  --> $DIR/read-to-local.rs:LL:CC
+   |
+LL |         assert_eq!(root, 0); // Parent Read
+   |         ^^^^^^^^^^^^^^^^^^^
+   = help: this corresponds to a loss of write permissions
+   = note: BACKTRACE (of the first span):
    = note: inside `main` at $DIR/read-to-local.rs:LL:CC
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace