Add a (1) and (2) to the data race errors

57 files changed, 113 insertions, 113 deletions

diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs
index 9f7be0f3b58..6f94d57bcc0 100644
--- a/src/tools/miri/src/diagnostics.rs
+++ b/src/tools/miri/src/diagnostics.rs
@@ -69,8 +69,8 @@ impl fmt::Display for TerminationInfo {
             DataRace { ptr, op1, op2 } =>
                 write!(
                     f,
-                    "Data race detected between {} on {} and {} on {} at {:?}. The {} is here",
-                    op1.action, op1.thread_info, op2.action, op2.thread_info, ptr, op1.action
+                    "Data race detected between (1) {} on {} and (2) {} on {} at {ptr:?}. (1) just happened here",
+                    op1.action, op1.thread_info, op2.action, op2.thread_info
                 ),
         }
     }
@@ -224,7 +224,7 @@ pub fn report_error<'tcx, 'mir>(
                 vec![(None, format!("use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead"))],
             DataRace { op2, .. } =>
                 vec![
-                    (Some(op2.span), format!("and the {} on {} is here", op2.action, op2.thread_info)),
+                    (Some(op2.span), format!("and (2) occurred earlier here")),
                     (None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")),
                     (None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")),
                 ],
diff --git a/src/tools/miri/tests/fail/data_race/alloc_read_race.rs b/src/tools/miri/tests/fail/data_race/alloc_read_race.rs
index 6040452a166..ba1d54e36c3 100644
--- a/src/tools/miri/tests/fail/data_race/alloc_read_race.rs
+++ b/src/tools/miri/tests/fail/data_race/alloc_read_race.rs
@@ -37,7 +37,7 @@ pub fn main() {
             let pointer = &*ptr.0;
 
             // Note: could also error due to reading uninitialized memory, but the data-race detector triggers first.
-            *pointer.load(Ordering::Relaxed) //~ ERROR: Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>`
+            *pointer.load(Ordering::Relaxed) //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Allocate on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr b/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr
index 9b487daccad..38b1ad3cfef 100644
--- a/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/alloc_read_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Allocate on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/alloc_read_race.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Relaxed)
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC. The Read is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Allocate on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Allocate on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/alloc_read_race.rs:LL:CC
    |
 LL |             pointer.store(Box::into_raw(Box::new_uninit()), Ordering::Relaxed);
diff --git a/src/tools/miri/tests/fail/data_race/alloc_write_race.rs b/src/tools/miri/tests/fail/data_race/alloc_write_race.rs
index 51d431b36f3..9f85fb13ab3 100644
--- a/src/tools/miri/tests/fail/data_race/alloc_write_race.rs
+++ b/src/tools/miri/tests/fail/data_race/alloc_write_race.rs
@@ -35,7 +35,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let pointer = &*ptr.0;
-            *pointer.load(Ordering::Relaxed) = 2; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>`
+            *pointer.load(Ordering::Relaxed) = 2; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Allocate on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr b/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr
index 7b1fcdf05b7..473a6945226 100644
--- a/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/alloc_write_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Allocate on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/alloc_write_race.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Relaxed) = 2;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Allocate on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Allocate on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Allocate on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/alloc_write_race.rs:LL:CC
    |
 LL |                 .store(Box::into_raw(Box::<usize>::new_uninit()) as *mut usize, Ordering::Relaxed);
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs
index 79c6760b7c4..4aa96de877a 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.rs
@@ -20,7 +20,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            (&*c.0).load(Ordering::SeqCst) //~ ERROR: Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>`
+            (&*c.0).load(Ordering::SeqCst) //~ ERROR: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr
index a66f73bf57d..565fba32808 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race1.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Atomic Load is here
+error: Undefined Behavior: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_read_na_write_race1.rs:LL:CC
    |
 LL |             (&*c.0).load(Ordering::SeqCst)
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Load on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Atomic Load is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_read_na_write_race1.rs:LL:CC
    |
 LL |             *(c.0 as *mut usize) = 32;
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs
index e069ac4ad6a..135017d35b4 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.rs
@@ -23,7 +23,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>`
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr
index 776ca8bc4d4..753a2961b49 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_read_na_write_race2.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_read_na_write_race2.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut() = 32;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Atomic Load on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Atomic Load on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_read_na_write_race2.rs:LL:CC
    |
 LL |             atomic_ref.load(Ordering::SeqCst)
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs
index 9c025a0153d..345b53ab5cd 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.rs
@@ -23,7 +23,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() //~ ERROR: Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>`
+            *atomic_ref.get_mut() //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr
index a59b4490941..5be597b7f56 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race1.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_write_na_read_race1.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut()
-   |             ^^^^^^^^^^^^^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC. The Read is here
+   |             ^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Atomic Store on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_write_na_read_race1.rs:LL:CC
    |
 LL |             atomic_ref.store(32, Ordering::SeqCst)
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs
index 30b3c486374..bc37f6442ea 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.rs
@@ -20,7 +20,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            (&*c.0).store(32, Ordering::SeqCst); //~ ERROR: Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>`
+            (&*c.0).store(32, Ordering::SeqCst); //~ ERROR: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr
index 5fb0821e540..2c21337029a 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_read_race2.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Atomic Store is here
+error: Undefined Behavior: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_write_na_read_race2.rs:LL:CC
    |
 LL |             (&*c.0).store(32, Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Store on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Atomic Store is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_write_na_read_race2.rs:LL:CC
    |
 LL |             let _val = *(c.0 as *mut usize);
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs
index 02b17cc57b6..f1647ce4a9d 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.rs
@@ -20,7 +20,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            (&*c.0).store(64, Ordering::SeqCst); //~ ERROR: Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>`
+            (&*c.0).store(64, Ordering::SeqCst); //~ ERROR: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr
index ec4e2da26bf..b10724aa67e 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race1.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Atomic Store is here
+error: Undefined Behavior: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_write_na_write_race1.rs:LL:CC
    |
 LL |             (&*c.0).store(64, Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Atomic Store on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Atomic Store is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_write_na_write_race1.rs:LL:CC
    |
 LL |             *(c.0 as *mut usize) = 32;
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs
index b5f4966d884..343b46ea4eb 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.rs
@@ -23,7 +23,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>`
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr
index d532ce4db67..63393a2a8bd 100644
--- a/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr
+++ b/src/tools/miri/tests/fail/data_race/atomic_write_na_write_race2.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/atomic_write_na_write_race2.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut() = 32;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Atomic Store on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Atomic Store on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/atomic_write_na_write_race2.rs:LL:CC
    |
 LL |             atomic_ref.store(64, Ordering::SeqCst);
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs
index 9922468e5f8..eecb980e905 100644
--- a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.rs
@@ -34,7 +34,7 @@ fn main() {
 
     let join2 = unsafe {
         spawn(move || {
-            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         })
     };
 
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr
index 0eb51d7c95e..26ab3c16735 100644
--- a/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_async_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dangling_thread_async_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dangling_thread_async_race.rs:LL:CC
    |
 LL |             *c.0 = 32;
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs b/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs
index 8c8a6ac87f3..3ead4eedd7f 100644
--- a/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_race.rs
@@ -33,6 +33,6 @@ fn main() {
     spawn(|| ()).join().unwrap();
 
     unsafe {
-        *c.0 = 64; //~ ERROR: Data race detected between Write on thread `main` and Write on thread `<unnamed>`
+        *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>`
     }
 }
diff --git a/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr b/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr
index bd1de464ea6..23ccb33e9a9 100644
--- a/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/dangling_thread_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dangling_thread_race.rs:LL:CC
    |
 LL |         *c.0 = 64;
-   |         ^^^^^^^^^ Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |         ^^^^^^^^^ Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dangling_thread_race.rs:LL:CC
    |
 LL |             *c.0 = 32;
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs
index 8e1216f5bf0..a94459ca4eb 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.rs
@@ -25,7 +25,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             __rust_dealloc(
-                //~^ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>`
+                //~^ ERROR: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>`
                 ptr.0 as *mut _,
                 std::mem::size_of::<usize>(),
                 std::mem::align_of::<usize>(),
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
index 051ba69c973..baf3f852164 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+error: Undefined Behavior: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dealloc_read_race1.rs:LL:CC
    |
 LL | /             __rust_dealloc(
@@ -7,9 +7,9 @@ LL | |                 ptr.0 as *mut _,
 LL | |                 std::mem::size_of::<usize>(),
 LL | |                 std::mem::align_of::<usize>(),
 LL | |             );
-   | |_____________^ Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+   | |_____________^ Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dealloc_read_race1.rs:LL:CC
    |
 LL |             let _val = *ptr.0;
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs
index 38f76af9de1..6e6b6af5a6f 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race2.rs
@@ -28,7 +28,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            // Also an error of the form: Data race detected between Read on thread `<unnamed>` and Deallocate on thread `<unnamed>`
+            // Also an error of the form: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
             // but the invalid allocation is detected first.
             *ptr.0 //~ ERROR: dereferenced after this allocation got freed
         });
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs
index 665e5ce4a17..ee3c66fb197 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.rs
@@ -35,7 +35,7 @@ pub fn main() {
                 sleep(Duration::from_millis(200));
 
                 // Now `stack_var` gets deallocated.
-            } //~ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>`
+            } //~ ERROR: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr
index c147f33b950..94d95d44ac8 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race_stack.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+error: Undefined Behavior: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dealloc_read_race_stack.rs:LL:CC
    |
 LL |             }
-   |             ^ Data race detected between Deallocate on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+   |             ^ Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dealloc_read_race_stack.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Acquire)
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs
index b36c6b5ac0e..041df291ed1 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.rs
@@ -24,7 +24,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             __rust_dealloc(
-                //~^ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>`
+                //~^ ERROR: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>`
                 ptr.0 as *mut _,
                 std::mem::size_of::<usize>(),
                 std::mem::align_of::<usize>(),
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
index de712752611..cce2701a03c 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
@@ -1,4 +1,4 @@
-error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Deallocate is here
+error: Undefined Behavior: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dealloc_write_race1.rs:LL:CC
    |
 LL | /             __rust_dealloc(
@@ -7,9 +7,9 @@ LL | |                 ptr.0 as *mut _,
 LL | |                 std::mem::size_of::<usize>(),
 LL | |                 std::mem::align_of::<usize>(),
 LL | |             );
-   | |_____________^ Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Deallocate is here
+   | |_____________^ Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dealloc_write_race1.rs:LL:CC
    |
 LL |             *ptr.0 = 2;
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs
index 4af8b904626..b94fa8a14a2 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race2.rs
@@ -27,7 +27,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            // Also an error of the form: Data race detected between Write on thread `<unnamed>` and Deallocate on thread `<unnamed>`
+            // Also an error of the form: Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
             // but the invalid allocation is detected first.
             *ptr.0 = 2; //~ ERROR: dereferenced after this allocation got freed
         });
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs
index f851ce95785..78f11c14fb1 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.rs
@@ -35,7 +35,7 @@ pub fn main() {
                 sleep(Duration::from_millis(200));
 
                 // Now `stack_var` gets deallocated.
-            } //~ ERROR: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>`
+            } //~ ERROR: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr
index 142c90b0b99..0f60926fb5b 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race_stack.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Deallocate is here
+error: Undefined Behavior: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/dealloc_write_race_stack.rs:LL:CC
    |
 LL |             }
-   |             ^ Data race detected between Deallocate on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Deallocate is here
+   |             ^ Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/dealloc_write_race_stack.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Acquire) = 3;
diff --git a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs
index 27aa16a122f..3d47b1accb3 100644
--- a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs
+++ b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.rs
@@ -30,7 +30,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr
index bb791300f56..e608342f8d7 100644
--- a/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr
+++ b/src/tools/miri/tests/fail/data_race/enable_after_join_to_main.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/enable_after_join_to_main.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/enable_after_join_to_main.rs:LL:CC
    |
 LL |             *c.0 = 32;
diff --git a/src/tools/miri/tests/fail/data_race/fence_after_load.rs b/src/tools/miri/tests/fail/data_race/fence_after_load.rs
index 4d436d51f98..8de61d14ac1 100644
--- a/src/tools/miri/tests/fail/data_race/fence_after_load.rs
+++ b/src/tools/miri/tests/fail/data_race/fence_after_load.rs
@@ -20,5 +20,5 @@ fn main() {
     // The fence is useless, since it did not happen-after the `store` in the other thread.
     // Hence this is a data race.
     // Also see https://github.com/rust-lang/miri/issues/2192.
-    unsafe { V = 2 } //~ERROR: Data race detected between Write on thread `main` and Write on thread `<unnamed>`
+    unsafe { V = 2 } //~ERROR: Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>`
 }
diff --git a/src/tools/miri/tests/fail/data_race/fence_after_load.stderr b/src/tools/miri/tests/fail/data_race/fence_after_load.stderr
index c44bc743ab6..9c1d92d14f8 100644
--- a/src/tools/miri/tests/fail/data_race/fence_after_load.stderr
+++ b/src/tools/miri/tests/fail/data_race/fence_after_load.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/fence_after_load.rs:LL:CC
    |
 LL |     unsafe { V = 2 }
-   |              ^^^^^ Data race detected between Write on thread `main` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |              ^^^^^ Data race detected between (1) Write on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/fence_after_load.rs:LL:CC
    |
 LL |         unsafe { V = 1 }
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race.rs b/src/tools/miri/tests/fail/data_race/read_write_race.rs
index b26ec6c4142..f18d2da8315 100644
--- a/src/tools/miri/tests/fail/data_race/read_write_race.rs
+++ b/src/tools/miri/tests/fail/data_race/read_write_race.rs
@@ -19,7 +19,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race.stderr b/src/tools/miri/tests/fail/data_race/read_write_race.stderr
index ac08d2d7901..e31bc5fbb4a 100644
--- a/src/tools/miri/tests/fail/data_race/read_write_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/read_write_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/read_write_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/read_write_race.rs:LL:CC
    |
 LL |             let _val = *c.0;
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs
index 2fbac173993..acbe2a09e97 100644
--- a/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs
+++ b/src/tools/miri/tests/fail/data_race/read_write_race_stack.rs
@@ -42,7 +42,7 @@ pub fn main() {
 
             sleep(Duration::from_millis(200));
 
-            stack_var //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+            stack_var //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {
diff --git a/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr
index 996f1ec6fab..09b704e0631 100644
--- a/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr
+++ b/src/tools/miri/tests/fail/data_race/read_write_race_stack.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/read_write_race_stack.rs:LL:CC
    |
 LL |             stack_var
-   |             ^^^^^^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+   |             ^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/read_write_race_stack.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Acquire) = 3;
diff --git a/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs b/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs
index 24040a94961..cc49e8a04f2 100644
--- a/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs
+++ b/src/tools/miri/tests/fail/data_race/relax_acquire_race.rs
@@ -37,7 +37,7 @@ pub fn main() {
 
         let j3 = spawn(move || {
             if SYNC.load(Ordering::Acquire) == 2 {
-                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
             } else {
                 0
             }
diff --git a/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr b/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr
index 4c3021d24d5..a996fc35002 100644
--- a/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/relax_acquire_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/relax_acquire_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+   |                 ^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/relax_acquire_race.rs:LL:CC
    |
 LL |             *c.0 = 1;
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race.rs b/src/tools/miri/tests/fail/data_race/release_seq_race.rs
index 2d7246858e1..ba917cd0dd4 100644
--- a/src/tools/miri/tests/fail/data_race/release_seq_race.rs
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race.rs
@@ -41,7 +41,7 @@ pub fn main() {
         let j3 = spawn(move || {
             sleep(Duration::from_millis(500));
             if SYNC.load(Ordering::Acquire) == 3 {
-                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
             } else {
                 0
             }
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race.stderr b/src/tools/miri/tests/fail/data_race/release_seq_race.stderr
index ee0853dca64..8b27a188563 100644
--- a/src/tools/miri/tests/fail/data_race/release_seq_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/release_seq_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+   |                 ^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/release_seq_race.rs:LL:CC
    |
 LL |             *c.0 = 1;
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs
index 0f974e1c56d..c34f4ebe424 100644
--- a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.rs
@@ -37,7 +37,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             if SYNC.load(Ordering::Acquire) == 2 {
-                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
             } else {
                 0
             }
diff --git a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr
index 8156fa717e7..a3561b1a269 100644
--- a/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr
+++ b/src/tools/miri/tests/fail/data_race/release_seq_race_same_thread.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/release_seq_race_same_thread.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+   |                 ^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/release_seq_race_same_thread.rs:LL:CC
    |
 LL |             *c.0 = 1;
diff --git a/src/tools/miri/tests/fail/data_race/rmw_race.rs b/src/tools/miri/tests/fail/data_race/rmw_race.rs
index 2d13da30b46..f96ebef284a 100644
--- a/src/tools/miri/tests/fail/data_race/rmw_race.rs
+++ b/src/tools/miri/tests/fail/data_race/rmw_race.rs
@@ -38,7 +38,7 @@ pub fn main() {
 
         let j3 = spawn(move || {
             if SYNC.load(Ordering::Acquire) == 3 {
-                *c.0 //~ ERROR: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
             } else {
                 0
             }
diff --git a/src/tools/miri/tests/fail/data_race/rmw_race.stderr b/src/tools/miri/tests/fail/data_race/rmw_race.stderr
index c8089cf06d9..9448d9059bf 100644
--- a/src/tools/miri/tests/fail/data_race/rmw_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/rmw_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/rmw_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between Read on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Read is here
+   |                 ^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/rmw_race.rs:LL:CC
    |
 LL |             *c.0 = 1;
diff --git a/src/tools/miri/tests/fail/data_race/stack_pop_race.rs b/src/tools/miri/tests/fail/data_race/stack_pop_race.rs
index cf5c2ed81cb..fb3ec5a22bd 100644
--- a/src/tools/miri/tests/fail/data_race/stack_pop_race.rs
+++ b/src/tools/miri/tests/fail/data_race/stack_pop_race.rs
@@ -21,4 +21,4 @@ fn race(local: i32) {
     // Deallocating the local (when `main` returns)
     // races with the read in the other thread.
     // Make sure the error points at this function's end, not just the call site.
-} //~ERROR: Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>`
+} //~ERROR: Data race detected between (1) Deallocate on thread `main` and (2) Read on thread `<unnamed>`
diff --git a/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr b/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr
index fb6f4470f80..0e2e2029009 100644
--- a/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/stack_pop_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+error: Undefined Behavior: Data race detected between (1) Deallocate on thread `main` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/stack_pop_race.rs:LL:CC
    |
 LL | }
-   |  ^ Data race detected between Deallocate on thread `main` and Read on thread `<unnamed>` at ALLOC. The Deallocate is here
+   |  ^ Data race detected between (1) Deallocate on thread `main` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/stack_pop_race.rs:LL:CC
    |
 LL |         let _val = unsafe { *ptr.0 };
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race.rs b/src/tools/miri/tests/fail/data_race/write_write_race.rs
index 60e9ac2ac6c..fe02d02f9dc 100644
--- a/src/tools/miri/tests/fail/data_race/write_write_race.rs
+++ b/src/tools/miri/tests/fail/data_race/write_write_race.rs
@@ -19,7 +19,7 @@ pub fn main() {
         });
 
         let j2 = spawn(move || {
-            *c.0 = 64; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
         });
 
         j1.join().unwrap();
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race.stderr b/src/tools/miri/tests/fail/data_race/write_write_race.stderr
index 27218cf77dd..dcc94a9d255 100644
--- a/src/tools/miri/tests/fail/data_race/write_write_race.stderr
+++ b/src/tools/miri/tests/fail/data_race/write_write_race.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/write_write_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/write_write_race.rs:LL:CC
    |
 LL |             *c.0 = 32;
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs b/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs
index 0a29dc13cba..c1c1b1fa6e3 100644
--- a/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs
+++ b/src/tools/miri/tests/fail/data_race/write_write_race_stack.rs
@@ -39,7 +39,7 @@ pub fn main() {
 
             sleep(Duration::from_millis(200));
 
-            stack_var = 1usize; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+            stack_var = 1usize; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
 
             // read to silence errors
             stack_var
diff --git a/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr b/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr
index 9f3dcf61701..8b0250593d5 100644
--- a/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr
+++ b/src/tools/miri/tests/fail/data_race/write_write_race_stack.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/write_write_race_stack.rs:LL:CC
    |
 LL |             stack_var = 1usize;
-   |             ^^^^^^^^^^^^^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |             ^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/write_write_race_stack.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Acquire) = 3;
diff --git a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.rs b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.rs
index 309d7a22be6..8c97a31c327 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.rs
+++ b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.rs
@@ -15,7 +15,7 @@ fn thread_1(p: SendPtr) {
 fn thread_2(p: SendPtr) {
     let p = p.0;
     unsafe {
-        *p = 5; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>`
+        *p = 5; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
     }
 }
 
diff --git a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.stderr b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.stderr
index ea2b8c8c0ac..790fd51ec37 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.stderr
+++ b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_read.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/retag_data_race_read.rs:LL:CC
    |
 LL |         *p = 5;
-   |         ^^^^^^ Data race detected between Write on thread `<unnamed>` and Read on thread `<unnamed>` at ALLOC. The Write is here
+   |         ^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Read on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/retag_data_race_read.rs:LL:CC
    |
 LL |         let _r = &*p;
diff --git a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.rs b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.rs
index 9368a0a919e..c1dded40d3c 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.rs
+++ b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.rs
@@ -15,7 +15,7 @@ fn thread_1(p: SendPtr) {
 fn thread_2(p: SendPtr) {
     let p = p.0;
     unsafe {
-        *p = 5; //~ ERROR: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>`
+        *p = 5; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
     }
 }
 
diff --git a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.stderr b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.stderr
index 34170bb0b3e..c5b8b4c41f5 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.stderr
+++ b/src/tools/miri/tests/fail/stacked_borrows/retag_data_race_write.stderr
@@ -1,10 +1,10 @@
-error: Undefined Behavior: Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
   --> $DIR/retag_data_race_write.rs:LL:CC
    |
 LL |         *p = 5;
-   |         ^^^^^^ Data race detected between Write on thread `<unnamed>` and Write on thread `<unnamed>` at ALLOC. The Write is here
+   |         ^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (1) just happened here
    |
-help: and the Write on thread `<unnamed>` is here
+help: and (2) occurred earlier here
   --> $DIR/retag_data_race_write.rs:LL:CC
    |
 LL |         let _r = &mut *p;