diagnostics: do not repeat the entire message in the span label

Author: RalfJung

src/tools/miri/src/diagnostics.rs

@@ -426,11 +426,17 @@ pub fn report_error<'tcx>(
         _ => {}
     }
 
-    msg.insert(0, format_interp_error(ecx.tcx.dcx(), e));
+    let mut primary_msg = String::new();
+    if let Some(title) = title {
+        write!(primary_msg, "{title}: ").unwrap();
+    }
+    write!(primary_msg, "{}", format_interp_error(ecx.tcx.dcx(), e)).unwrap();
+
+    msg.insert(0, format!("{} occurred here", title.unwrap_or("error")));
 
     report_msg(
         DiagLevel::Error,
-        if let Some(title) = title { format!("{title}: {}", msg[0]) } else { msg[0].clone() },
+        primary_msg,
         msg,
         vec![],
         helps,

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using uninitialized data, but this operation requires
   --> tests/fail-dep/concurrency/libc_pthread_cond_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_cond_destroy(cond.as_mut_ptr());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_move.init.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: `pthread_cond_t` can't be moved after first use
   --> tests/fail-dep/concurrency/libc_pthread_cond_move.rs:LL:CC
    |
 LL |         libc::pthread_cond_destroy(cond2.as_mut_ptr());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `pthread_cond_t` can't be moved after first use
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_cond_move.static_initializer.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: `pthread_cond_t` can't be moved after first use
   --> tests/fail-dep/concurrency/libc_pthread_cond_move.rs:LL:CC
    |
 LL |         libc::pthread_cond_destroy(&mut cond2 as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `pthread_cond_t` can't be moved after first use
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using uninitialized data, but this operation requires
   --> tests/fail-dep/concurrency/libc_pthread_condattr_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_condattr_destroy(attr.as_mut_ptr());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_few_args.stderr

@@ -1,6 +1,6 @@
 error: Undefined Behavior: calling a function with more arguments than it expected
    |
-   = note: calling a function with more arguments than it expected
+   = note: Undefined Behavior occurred here
    = note: (no span available)
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_create_too_many_args.stderr

@@ -1,6 +1,6 @@
 error: Undefined Behavior: calling a function with fewer arguments than it requires
    |
-   = note: calling a function with fewer arguments than it requires
+   = note: Undefined Behavior occurred here
    = note: (no span available)
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_join_detached.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to join a detached thread
   --> tests/fail-dep/concurrency/libc_pthread_join_detached.rs:LL:CC
    |
 LL |         assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join a detached thread
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_join_joined.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to join an already joined thread
   --> tests/fail-dep/concurrency/libc_pthread_join_joined.rs:LL:CC
    |
 LL |         assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join an already joined thread
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_join_main.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to join a detached thread
   --> tests/fail-dep/concurrency/libc_pthread_join_main.rs:LL:CC
    |
 LL |             assert_eq!(libc::pthread_join(thread_id, ptr::null_mut()), 0);
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join a detached thread
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_join_multiple.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to join an already joined thread
   --> tests/fail-dep/concurrency/libc_pthread_join_multiple.rs:LL:CC
    |
 LL | ...   assert_eq!(libc::pthread_join(native_copy, ptr::null_mut()), 0);
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join an already joined thread
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_join_self.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to join itself
   --> tests/fail-dep/concurrency/libc_pthread_join_self.rs:LL:CC
    |
 LL |             assert_eq!(libc::pthread_join(native, ptr::null_mut()), 0);
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to join itself
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_NULL_reentrant.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to acquire default mutex already locked by the
   --> tests/fail-dep/concurrency/libc_pthread_mutex_NULL_reentrant.rs:LL:CC
    |
 LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to acquire default mutex already locked by the current thread
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.stderr

@@ -2,7 +2,7 @@ error: deadlock: the evaluated program deadlocked
   --> tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC
    |
 LL |             assert_eq!(libc::pthread_mutex_lock(lock_copy.0.get() as *mut _), 0);
-   |                                                                            ^ the evaluated program deadlocked
+   |                                                                            ^ deadlock occurred here
    |
    = note: BACKTRACE on thread `unnamed-ID`:
    = note: inside closure at tests/fail-dep/concurrency/libc_pthread_mutex_deadlock.rs:LL:CC

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_default_reentrant.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to acquire default mutex already locked by the
   --> tests/fail-dep/concurrency/libc_pthread_mutex_default_reentrant.rs:LL:CC
    |
 LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to acquire default mutex already locked by the current thread
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_destroy_locked.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: destroyed a locked mutex
   --> tests/fail-dep/concurrency/libc_pthread_mutex_destroy_locked.rs:LL:CC
    |
 LL |         libc::pthread_mutex_destroy(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked mutex
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using uninitialized data, but this operation requires
   --> tests/fail-dep/concurrency/libc_pthread_mutex_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_mutex_destroy(mutex.as_mut_ptr());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_move.init.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: `pthread_mutex_t` can't be moved after first use
   --> tests/fail-dep/concurrency/libc_pthread_mutex_move.rs:LL:CC
    |
 LL |         libc::pthread_mutex_lock(&mut m2 as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `pthread_mutex_t` can't be moved after first use
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_move.static_initializer.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: `pthread_mutex_t` can't be moved after first use
   --> tests/fail-dep/concurrency/libc_pthread_mutex_move.rs:LL:CC
    |
 LL |         libc::pthread_mutex_unlock(&mut m2 as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `pthread_mutex_t` can't be moved after first use
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.stderr

@@ -2,7 +2,7 @@ error: deadlock: the evaluated program deadlocked
   --> tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.rs:LL:CC
    |
 LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program deadlocked
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deadlock occurred here
    |
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_mutex_normal_reentrant.rs:LL:CC

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_normal_unlock_unlocked.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: unlocked a PTHREAD_MUTEX_NORMAL mutex that was not lo
   --> tests/fail-dep/concurrency/libc_pthread_mutex_normal_unlock_unlocked.rs:LL:CC
    |
 LL |         libc::pthread_mutex_unlock(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked a PTHREAD_MUTEX_NORMAL mutex that was not locked by the current thread
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_staticinit_reentrant.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: trying to acquire default mutex already locked by the
   --> tests/fail-dep/concurrency/libc_pthread_mutex_staticinit_reentrant.rs:LL:CC
    |
 LL |         libc::pthread_mutex_lock(&mut mutex as *mut _);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trying to acquire default mutex already locked by the current thread
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.stderr

@@ -1,8 +1,8 @@
 error: Undefined Behavior: unlocked a default mutex that was not locked by the current thread
   --> tests/fail-dep/concurrency/libc_pthread_mutex_wrong_owner.rs:LL:CC
    |
-LL | ...t_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0);
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked a default mutex that was not locked by the current thread
+LL | ...   assert_eq!(libc::pthread_mutex_unlock(lock_copy.0.get() as *mut _), 0);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using uninitialized data, but this operation requires
   --> tests/fail-dep/concurrency/libc_pthread_mutexattr_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_mutexattr_destroy(attr.as_mut_ptr());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_read_locked.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: destroyed a locked rwlock
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_read_locked.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_destroy(rw.get());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked rwlock
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_write_locked.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: destroyed a locked rwlock
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_destroy_write_locked.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_destroy(rw.get());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ destroyed a locked rwlock
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: using uninitialized data, but this operation requires
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_double_destroy.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_destroy(&mut lock);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_read_write_deadlock_single_thread.stderr

@@ -2,7 +2,7 @@ error: deadlock: the evaluated program deadlocked
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_read_write_deadlock_single_thread.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_wrlock(rw.get());
-   |                                             ^ the evaluated program deadlocked
+   |                                             ^ deadlock occurred here
    |
    = note: BACKTRACE:
    = note: inside `main` at tests/fail-dep/concurrency/libc_pthread_rwlock_read_write_deadlock_single_thread.rs:LL:CC

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: unlocked an rwlock that was not locked by the active
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_read_wrong_owner.rs:LL:CC
    |
 LL | ...   assert_eq!(libc::pthread_rwlock_unlock(lock_copy.0.get() as *mut _), 0);
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked an rwlock that was not locked by the active thread
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information

src/tools/miri/tests/fail-dep/concurrency/libc_pthread_rwlock_unlock_unlocked.stderr

@@ -2,7 +2,7 @@ error: Undefined Behavior: unlocked an rwlock that was not locked by the active
   --> tests/fail-dep/concurrency/libc_pthread_rwlock_unlock_unlocked.rs:LL:CC
    |
 LL |         libc::pthread_rwlock_unlock(rw.get());
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unlocked an rwlock that was not locked by the active thread
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Undefined Behavior occurred here
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information