give some more help for the unusual data races

src/concurrency/data_race.rs

@@ -41,7 +41,6 @@
 //! on the data-race detection code.
 
 use std::{
-    borrow::Cow,
     cell::{Cell, Ref, RefCell, RefMut},
     fmt::Debug,
     mem,
@@ -199,7 +198,7 @@ struct AtomicMemoryCellClocks {
 /// are all treated as writes for the purpose
 /// of the data-race detector.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
-enum WriteType {
+enum NaWriteType {
     /// Allocate memory.
     Allocate,
 
@@ -212,12 +211,48 @@ enum WriteType {
     /// (Same for `Allocate` above.)
     Deallocate,
 }
-impl WriteType {
-    fn get_descriptor(self) -> &'static str {
+
+impl NaWriteType {
+    fn description(self) -> &'static str {
         match self {
-            WriteType::Allocate => "Allocate",
-            WriteType::Write => "Write",
-            WriteType::Deallocate => "Deallocate",
+            NaWriteType::Allocate => "creating a new allocation",
+            NaWriteType::Write => "non-atomic write",
+            NaWriteType::Deallocate => "deallocation",
+        }
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+enum AccessType {
+    NaRead,
+    NaWrite(NaWriteType),
+    AtomicLoad,
+    AtomicStore,
+    AtomicRmw,
+}
+
+impl AccessType {
+    fn description(self) -> &'static str {
+        match self {
+            AccessType::NaRead => "non-atomic read",
+            AccessType::NaWrite(w) => w.description(),
+            AccessType::AtomicLoad => "atomic load",
+            AccessType::AtomicStore => "atomic store",
+            AccessType::AtomicRmw => "atomic read-modify-write",
+        }
+    }
+
+    fn is_atomic(self) -> bool {
+        match self {
+            AccessType::AtomicLoad | AccessType::AtomicStore | AccessType::AtomicRmw => true,
+            AccessType::NaRead | AccessType::NaWrite(_) => false,
+        }
+    }
+
+    fn is_read(self) -> bool {
+        match self {
+            AccessType::AtomicLoad | AccessType::NaRead => true,
+            AccessType::NaWrite(_) | AccessType::AtomicStore | AccessType::AtomicRmw => false,
         }
     }
 }
@@ -234,7 +269,7 @@ struct MemoryCellClocks {
     /// The type of operation that the write index represents,
     /// either newly allocated memory, a non-atomic write or
     /// a deallocation of memory.
-    write_type: WriteType,
+    write_type: NaWriteType,
 
     /// The vector-clock of all non-atomic reads that happened since the last non-atomic write
     /// (i.e., we join together the "singleton" clocks corresponding to each read). It is reset to
@@ -265,7 +300,7 @@ impl MemoryCellClocks {
         MemoryCellClocks {
             read: VClock::default(),
             write: (alloc_index, alloc),
-            write_type: WriteType::Allocate,
+            write_type: NaWriteType::Allocate,
             atomic_ops: None,
         }
     }
@@ -488,7 +523,7 @@ impl MemoryCellClocks {
         &mut self,
         thread_clocks: &mut ThreadClockSet,
         index: VectorIdx,
-        write_type: WriteType,
+        write_type: NaWriteType,
         current_span: Span,
     ) -> Result<(), DataRace> {
         log::trace!("Unsynchronized write with vectors: {:#?} :: {:#?}", self, thread_clocks);
@@ -838,48 +873,45 @@ impl VClockAlloc {
         global: &GlobalState,
         thread_mgr: &ThreadManager<'_, '_>,
         mem_clocks: &MemoryCellClocks,
-        action: &str,
-        is_atomic: bool,
+        access: AccessType,
         access_size: Size,
         ptr_dbg: Pointer<AllocId>,
     ) -> InterpResult<'tcx> {
         let (current_index, current_clocks) = global.current_thread_state(thread_mgr);
-        let mut action = Cow::Borrowed(action);
-        let mut involves_non_atomic = true;
+        let mut other_size = None; // if `Some`, this was a size-mismatch race
         let write_clock;
-        let (other_action, other_thread, other_clock) =
+        let (other_access, other_thread, other_clock) =
             // First check the atomic-nonatomic cases. If it looks like multiple
             // cases apply, this one should take precedence, else it might look like
             // we are reporting races between two non-atomic reads.
-            if !is_atomic &&
+            if !access.is_atomic() &&
                 let Some(atomic) = mem_clocks.atomic() &&
                 let Some(idx) = Self::find_gt_index(&atomic.write_vector, &current_clocks.clock)
             {
-                (format!("Atomic Store"), idx, &atomic.write_vector)
-            } else if !is_atomic &&
+                (AccessType::AtomicStore, idx, &atomic.write_vector)
+            } else if !access.is_atomic() &&
                 let Some(atomic) = mem_clocks.atomic() &&
                 let Some(idx) = Self::find_gt_index(&atomic.read_vector, &current_clocks.clock)
             {
-                (format!("Atomic Load"), idx, &atomic.read_vector)
+                (AccessType::AtomicLoad, idx, &atomic.read_vector)
             // Then check races with non-atomic writes/reads.
             } else if mem_clocks.write.1 > current_clocks.clock[mem_clocks.write.0] {
                 write_clock = mem_clocks.write();
-                (mem_clocks.write_type.get_descriptor().to_owned(), mem_clocks.write.0, &write_clock)
+                (AccessType::NaWrite(mem_clocks.write_type), mem_clocks.write.0, &write_clock)
             } else if let Some(idx) = Self::find_gt_index(&mem_clocks.read, &current_clocks.clock) {
-                (format!("Read"), idx, &mem_clocks.read)
+                (AccessType::NaRead, idx, &mem_clocks.read)
             // Finally, mixed-size races.
-            } else if is_atomic && let Some(atomic) = mem_clocks.atomic() && atomic.size != access_size {
+            } else if access.is_atomic() && let Some(atomic) = mem_clocks.atomic() && atomic.size != access_size {
                 // This is only a race if we are not synchronized with all atomic accesses, so find
                 // the one we are not synchronized with.
-                involves_non_atomic = false;
-                action = format!("{}-byte (different-size) {action}", access_size.bytes()).into();
+                other_size = Some(atomic.size);
                 if let Some(idx) = Self::find_gt_index(&atomic.write_vector, &current_clocks.clock)
                     {
-                        (format!("{}-byte Atomic Store", atomic.size.bytes()), idx, &atomic.write_vector)
+                        (AccessType::AtomicStore, idx, &atomic.write_vector)
                     } else if let Some(idx) =
                         Self::find_gt_index(&atomic.read_vector, &current_clocks.clock)
                     {
-                        (format!("{}-byte Atomic Load", atomic.size.bytes()), idx, &atomic.read_vector)
+                        (AccessType::AtomicLoad, idx, &atomic.read_vector)
                     } else {
                         unreachable!(
                             "Failed to report data-race for mixed-size access: no race found"
@@ -892,18 +924,39 @@ impl VClockAlloc {
         // Load elaborated thread information about the racing thread actions.
         let current_thread_info = global.print_thread_metadata(thread_mgr, current_index);
         let other_thread_info = global.print_thread_metadata(thread_mgr, other_thread);
+        let involves_non_atomic = !access.is_atomic() || !other_access.is_atomic();
 
         // Throw the data-race detection.
+        let extra = if other_size.is_some() {
+            assert!(!involves_non_atomic);
+            Some("overlapping unsynchronized atomic accesses must use the same access size")
+        } else if access.is_read() && other_access.is_read() {
+            assert!(involves_non_atomic);
+            Some(
+                "overlapping atomic and non-atomic accesses must be synchronized, even if both are read-only",
+            )
+        } else {
+            None
+        };
         Err(err_machine_stop!(TerminationInfo::DataRace {
             involves_non_atomic,
+            extra,
             ptr: ptr_dbg,
             op1: RacingOp {
-                action: other_action.to_string(),
+                action: if let Some(other_size) = other_size {
+                    format!("{}-byte {}", other_size.bytes(), other_access.description())
+                } else {
+                    other_access.description().to_owned()
+                },
                 thread_info: other_thread_info,
                 span: other_clock.as_slice()[other_thread.index()].span_data(),
             },
             op2: RacingOp {
-                action: action.to_string(),
+                action: if other_size.is_some() {
+                    format!("{}-byte {}", access_size.bytes(), access.description())
+                } else {
+                    access.description().to_owned()
+                },
                 thread_info: current_thread_info,
                 span: current_clocks.clock.as_slice()[current_index.index()].span_data(),
             },
@@ -938,8 +991,7 @@ impl VClockAlloc {
                         global,
                         &machine.threads,
                         mem_clocks,
-                        "Read",
-                        /* is_atomic */ false,
+                        AccessType::NaRead,
                         access_range.size,
                         Pointer::new(alloc_id, Size::from_bytes(mem_clocks_range.start)),
                     );
@@ -956,7 +1008,7 @@ impl VClockAlloc {
         &mut self,
         alloc_id: AllocId,
         access_range: AllocRange,
-        write_type: WriteType,
+        write_type: NaWriteType,
         machine: &mut MiriMachine<'_, '_>,
     ) -> InterpResult<'tcx> {
         let current_span = machine.current_span();
@@ -978,8 +1030,7 @@ impl VClockAlloc {
                         global,
                         &machine.threads,
                         mem_clocks,
-                        write_type.get_descriptor(),
-                        /* is_atomic */ false,
+                        AccessType::NaWrite(write_type),
                         access_range.size,
                         Pointer::new(alloc_id, Size::from_bytes(mem_clocks_range.start)),
                     );
@@ -1001,7 +1052,7 @@ impl VClockAlloc {
         range: AllocRange,
         machine: &mut MiriMachine<'_, '_>,
     ) -> InterpResult<'tcx> {
-        self.unique_access(alloc_id, range, WriteType::Write, machine)
+        self.unique_access(alloc_id, range, NaWriteType::Write, machine)
     }
 
     /// Detect data-races for an unsynchronized deallocate operation, will not perform
@@ -1014,7 +1065,7 @@ impl VClockAlloc {
         range: AllocRange,
         machine: &mut MiriMachine<'_, '_>,
     ) -> InterpResult<'tcx> {
-        self.unique_access(alloc_id, range, WriteType::Deallocate, machine)
+        self.unique_access(alloc_id, range, NaWriteType::Deallocate, machine)
     }
 }
 
@@ -1104,7 +1155,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
         this.validate_atomic_op(
             place,
             atomic,
-            "Atomic Load",
+            AccessType::AtomicLoad,
             move |memory, clocks, index, atomic| {
                 if atomic == AtomicReadOrd::Relaxed {
                     memory.load_relaxed(&mut *clocks, index, place.layout.size)
@@ -1126,7 +1177,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
         this.validate_atomic_op(
             place,
             atomic,
-            "Atomic Store",
+            AccessType::AtomicStore,
             move |memory, clocks, index, atomic| {
                 if atomic == AtomicWriteOrd::Relaxed {
                     memory.store_relaxed(clocks, index, place.layout.size)
@@ -1148,26 +1199,31 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
         let acquire = matches!(atomic, Acquire | AcqRel | SeqCst);
         let release = matches!(atomic, Release | AcqRel | SeqCst);
         let this = self.eval_context_mut();
-        this.validate_atomic_op(place, atomic, "Atomic RMW", move |memory, clocks, index, _| {
-            if acquire {
-                memory.load_acquire(clocks, index, place.layout.size)?;
-            } else {
-                memory.load_relaxed(clocks, index, place.layout.size)?;
-            }
-            if release {
-                memory.rmw_release(clocks, index, place.layout.size)
-            } else {
-                memory.rmw_relaxed(clocks, index, place.layout.size)
-            }
-        })
+        this.validate_atomic_op(
+            place,
+            atomic,
+            AccessType::AtomicRmw,
+            move |memory, clocks, index, _| {
+                if acquire {
+                    memory.load_acquire(clocks, index, place.layout.size)?;
+                } else {
+                    memory.load_relaxed(clocks, index, place.layout.size)?;
+                }
+                if release {
+                    memory.rmw_release(clocks, index, place.layout.size)
+                } else {
+                    memory.rmw_relaxed(clocks, index, place.layout.size)
+                }
+            },
+        )
     }
 
     /// Generic atomic operation implementation
     fn validate_atomic_op<A: Debug + Copy>(
         &self,
         place: &MPlaceTy<'tcx, Provenance>,
         atomic: A,
-        description: &str,
+        access: AccessType,
         mut op: impl FnMut(
             &mut MemoryCellClocks,
             &mut ThreadClockSet,
@@ -1176,6 +1232,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
         ) -> Result<(), DataRace>,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_ref();
+        assert!(access.is_atomic());
         if let Some(data_race) = &this.machine.data_race {
             if data_race.race_detecting() {
                 let size = place.layout.size;
@@ -1185,7 +1242,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
                 let alloc_meta = this.get_alloc_extra(alloc_id)?.data_race.as_ref().unwrap();
                 log::trace!(
                     "Atomic op({}) with ordering {:?} on {:?} (size={})",
-                    description,
+                    access.description(),
                     &atomic,
                     place.ptr(),
                     size.bytes()
@@ -1207,8 +1264,7 @@ trait EvalContextPrivExt<'mir, 'tcx: 'mir>: MiriInterpCxExt<'mir, 'tcx> {
                                     data_race,
                                     &this.machine.threads,
                                     mem_clocks,
-                                    description,
-                                    /* is_atomic */ true,
+                                    access,
                                     place.layout.size,
                                     Pointer::new(
                                         alloc_id,

src/diagnostics.rs

@@ -47,6 +47,7 @@ pub enum TerminationInfo {
         ptr: Pointer,
         op1: RacingOp,
         op2: RacingOp,
+        extra: Option<&'static str>,
     },
 }
 
@@ -75,7 +76,7 @@ impl fmt::Display for TerminationInfo {
                 write!(f, "multiple definitions of symbol `{link_name}`"),
             SymbolShimClashing { link_name, .. } =>
                 write!(f, "found `{link_name}` symbol definition that clashes with a built-in shim",),
-            DataRace { involves_non_atomic, ptr, op1, op2 } =>
+            DataRace { involves_non_atomic, ptr, op1, op2, .. } =>
                 write!(
                     f,
                     "{} detected between (1) {} on {} and (2) {} on {} at {ptr:?}. (2) just happened here",
@@ -266,12 +267,16 @@ pub fn report_error<'tcx, 'mir>(
                 vec![(Some(*span), format!("the `{link_name}` symbol is defined here"))],
             Int2PtrWithStrictProvenance =>
                 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 { op1, .. } =>
-                vec![
-                    (Some(op1.span), format!("and (1) 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")),
-                ],
+            DataRace { op1, extra, .. } => {
+                let mut helps = vec![(Some(op1.span), format!("and (1) occurred earlier here"))];
+                if let Some(extra) = extra {
+                    helps.push((None, format!("{extra}")))
+                }
+                helps.push((None, format!("this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior")));
+                helps.push((None, format!("see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information")));
+                helps
+            }
+                ,
             _ => vec![],
         };
         (title, helps)

tests/fail/both_borrows/retag_data_race_write.rs

@@ -17,7 +17,7 @@ fn thread_1(p: SendPtr) {
 fn thread_2(p: SendPtr) {
     let p = p.0;
     unsafe {
-        *p = 5; //~ ERROR: /Data race detected between \(1\) (Read|Write) on thread `<unnamed>` and \(2\) Write on thread `<unnamed>`/
+        *p = 5; //~ ERROR: /Data race detected between \(1\) non-atomic (read|write) on thread `<unnamed>` and \(2\) non-atomic write on thread `<unnamed>`/
     }
 }
 

tests/fail/both_borrows/retag_data_race_write.stack.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/retag_data_race_write.rs:LL:CC
    |
 LL |         *p = 5;
-   |         ^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |         ^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/retag_data_race_write.rs:LL:CC

tests/fail/both_borrows/retag_data_race_write.tree.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/retag_data_race_write.rs:LL:CC
    |
 LL |         *p = 5;
-   |         ^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |         ^^^^^^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/retag_data_race_write.rs:LL:CC

tests/fail/data_race/alloc_read_race.rs

@@ -39,7 +39,7 @@ 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 (1) Allocate on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+            *pointer.load(Ordering::Relaxed) //~ ERROR: Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/alloc_read_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Allocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/alloc_read_race.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Relaxed)
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Allocate on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/alloc_read_race.rs:LL:CC

tests/fail/data_race/alloc_write_race.rs

@@ -37,7 +37,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let ptr = ptr; // avoid field capturing
             let pointer = &*ptr.0;
-            *pointer.load(Ordering::Relaxed) = 2; //~ ERROR: Data race detected between (1) Allocate on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *pointer.load(Ordering::Relaxed) = 2; //~ ERROR: Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/alloc_write_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Allocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/alloc_write_race.rs:LL:CC
    |
 LL |             *pointer.load(Ordering::Relaxed) = 2;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Allocate on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) creating a new allocation on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/alloc_write_race.rs:LL:CC

tests/fail/data_race/atomic_read_na_write_race1.rs

@@ -22,7 +22,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            (&*c.0).load(Ordering::SeqCst) //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>`
+            (&*c.0).load(Ordering::SeqCst) //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic load on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_read_na_write_race1.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_read_na_write_race1.rs:LL:CC
    |
 LL |             (&*c.0).load(Ordering::SeqCst)
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_read_na_write_race1.rs:LL:CC

tests/fail/data_race/atomic_read_na_write_race2.rs

@@ -25,7 +25,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_read_na_write_race2.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_read_na_write_race2.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut() = 32;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_read_na_write_race2.rs:LL:CC

tests/fail/data_race/atomic_write_na_read_race1.rs

@@ -25,7 +25,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() //~ ERROR: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+            *atomic_ref.get_mut() //~ ERROR: Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_write_na_read_race1.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_write_na_read_race1.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut()
-   |             ^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_write_na_read_race1.rs:LL:CC

tests/fail/data_race/atomic_write_na_read_race2.rs

@@ -22,7 +22,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            (&*c.0).store(32, Ordering::SeqCst); //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>`
+            (&*c.0).store(32, Ordering::SeqCst); //~ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic store on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_write_na_read_race2.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_write_na_read_race2.rs:LL:CC
    |
 LL |             (&*c.0).store(32, Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_write_na_read_race2.rs:LL:CC

tests/fail/data_race/atomic_write_na_write_race1.rs

@@ -22,7 +22,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            (&*c.0).store(64, Ordering::SeqCst); //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>`
+            (&*c.0).store(64, Ordering::SeqCst); //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic store on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_write_na_write_race1.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_write_na_write_race1.rs:LL:CC
    |
 LL |             (&*c.0).store(64, Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_write_na_write_race1.rs:LL:CC

tests/fail/data_race/atomic_write_na_write_race2.rs

@@ -25,7 +25,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
             let atomic_ref = &mut *c.0;
-            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *atomic_ref.get_mut() = 32; //~ ERROR: Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/atomic_write_na_write_race2.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/atomic_write_na_write_race2.rs:LL:CC
    |
 LL |             *atomic_ref.get_mut() = 32;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Atomic Store on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) atomic store on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/atomic_write_na_write_race2.rs:LL:CC

tests/fail/data_race/dangling_thread_async_race.rs

@@ -36,7 +36,7 @@ fn main() {
     let join2 = unsafe {
         spawn(move || {
             let c = c; // capture `c`, not just its field.
-            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         })
     };
 

tests/fail/data_race/dangling_thread_async_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/dangling_thread_async_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dangling_thread_async_race.rs:LL:CC

tests/fail/data_race/dangling_thread_race.rs

@@ -34,6 +34,6 @@ fn main() {
     spawn(|| ()).join().unwrap();
 
     unsafe {
-        *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `main`
+        *c.0 = 64; //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main`
     }
 }

tests/fail/data_race/dangling_thread_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `main` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main` at ALLOC. (2) just happened here
   --> $DIR/dangling_thread_race.rs:LL:CC
    |
 LL |         *c.0 = 64;
-   |         ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `main` at ALLOC. (2) just happened here
+   |         ^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dangling_thread_race.rs:LL:CC

tests/fail/data_race/dealloc_read_race1.rs

@@ -27,7 +27,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let ptr = ptr; // avoid field capturing
             __rust_dealloc(
-                //~^ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
+                //~^ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>`
                 ptr.0 as *mut _,
                 std::mem::size_of::<usize>(),
                 std::mem::align_of::<usize>(),

tests/fail/data_race/dealloc_read_race1.stderr

@@ -1,4 +1,4 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/dealloc_read_race1.rs:LL:CC
    |
 LL | /             __rust_dealloc(
@@ -7,7 +7,7 @@ LL | |                 ptr.0 as *mut _,
 LL | |                 std::mem::size_of::<usize>(),
 LL | |                 std::mem::align_of::<usize>(),
 LL | |             );
-   | |_____________^ Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+   | |_____________^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dealloc_read_race1.rs:LL:CC

tests/fail/data_race/dealloc_read_race2.rs

@@ -30,7 +30,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let ptr = ptr; // avoid field capturing
-            // Also an error of the form: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+            // Also an error of the form: Data race detected between (1) deallocation on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
             // but the invalid allocation is detected first.
             *ptr.0 //~ ERROR: has been freed
         });

tests/fail/data_race/dealloc_read_race_stack.rs

@@ -36,7 +36,7 @@ pub fn main() {
                 sleep(Duration::from_millis(200));
 
                 // Now `stack_var` gets deallocated.
-            } //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
+            } //~ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {

tests/fail/data_race/dealloc_read_race_stack.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/dealloc_read_race_stack.rs:LL:CC
    |
 LL |             }
-   |             ^ Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dealloc_read_race_stack.rs:LL:CC

tests/fail/data_race/dealloc_write_race1.rs

@@ -26,7 +26,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let ptr = ptr; // avoid field capturing
             __rust_dealloc(
-                //~^ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
+                //~^ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>`
                 ptr.0 as *mut _,
                 std::mem::size_of::<usize>(),
                 std::mem::align_of::<usize>(),

tests/fail/data_race/dealloc_write_race1.stderr

@@ -1,4 +1,4 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/dealloc_write_race1.rs:LL:CC
    |
 LL | /             __rust_dealloc(
@@ -7,7 +7,7 @@ LL | |                 ptr.0 as *mut _,
 LL | |                 std::mem::size_of::<usize>(),
 LL | |                 std::mem::align_of::<usize>(),
 LL | |             );
-   | |_____________^ Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+   | |_____________^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dealloc_write_race1.rs:LL:CC

tests/fail/data_race/dealloc_write_race2.rs

@@ -29,7 +29,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let ptr = ptr; // avoid field capturing
-            // Also an error of the form: Data race detected between (1) Deallocate on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            // Also an error of the form: Data race detected between (1) deallocation on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
             // but the invalid allocation is detected first.
             *ptr.0 = 2; //~ ERROR: has been freed
         });

tests/fail/data_race/dealloc_write_race_stack.rs

@@ -36,7 +36,7 @@ pub fn main() {
                 sleep(Duration::from_millis(200));
 
                 // Now `stack_var` gets deallocated.
-            } //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>`
+            } //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {

tests/fail/data_race/dealloc_write_race_stack.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/dealloc_write_race_stack.rs:LL:CC
    |
 LL |             }
-   |             ^ Data race detected between (1) Write on thread `<unnamed>` and (2) Deallocate on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) deallocation on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/dealloc_write_race_stack.rs:LL:CC

tests/fail/data_race/enable_after_join_to_main.rs

@@ -32,7 +32,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/enable_after_join_to_main.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/enable_after_join_to_main.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/enable_after_join_to_main.rs:LL:CC

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 (1) Write on thread `<unnamed>` and (2) Write on thread `main`
+    unsafe { V = 2 } //~ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main`
 }

tests/fail/data_race/fence_after_load.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `main` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main` at ALLOC. (2) just happened here
   --> $DIR/fence_after_load.rs:LL:CC
    |
 LL |     unsafe { V = 2 }
-   |              ^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `main` at ALLOC. (2) just happened here
+   |              ^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `main` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/fence_after_load.rs:LL:CC

tests/fail/data_race/mixed_size_read.rs

@@ -19,7 +19,7 @@ fn main() {
         });
         s.spawn(|| {
             a8[0].load(Ordering::SeqCst);
-            //~^ ERROR: Race condition detected between (1) 2-byte Atomic Load on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Load on thread `<unnamed>`
+            //~^ ERROR: Race condition detected between (1) 2-byte atomic load on thread `<unnamed>` and (2) 1-byte atomic load on thread `<unnamed>`
         });
     });
 }

tests/fail/data_race/mixed_size_read.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Race condition detected between (1) 2-byte Atomic Load on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Race condition detected between (1) 2-byte atomic load on thread `<unnamed>` and (2) 1-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/mixed_size_read.rs:LL:CC
    |
 LL |             a8[0].load(Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 2-byte Atomic Load on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 2-byte atomic load on thread `<unnamed>` and (2) 1-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/mixed_size_read.rs:LL:CC
    |
 LL |             a16.load(Ordering::SeqCst);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: overlapping unsynchronized atomic accesses must use the same access size
    = 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
    = note: BACKTRACE (of the first span):

tests/fail/data_race/mixed_size_write.rs

@@ -19,7 +19,7 @@ fn main() {
         });
         s.spawn(|| {
             a8[0].store(1, Ordering::SeqCst);
-            //~^ ERROR: Race condition detected between (1) 2-byte Atomic Store on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Store on thread `<unnamed>`
+            //~^ ERROR: Race condition detected between (1) 2-byte atomic store on thread `<unnamed>` and (2) 1-byte atomic store on thread `<unnamed>`
         });
     });
 }

tests/fail/data_race/mixed_size_write.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Race condition detected between (1) 2-byte Atomic Store on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Race condition detected between (1) 2-byte atomic store on thread `<unnamed>` and (2) 1-byte atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/mixed_size_write.rs:LL:CC
    |
 LL |             a8[0].store(1, Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 2-byte Atomic Store on thread `<unnamed>` and (2) 1-byte (different-size) Atomic Store on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 2-byte atomic store on thread `<unnamed>` and (2) 1-byte atomic store on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/mixed_size_write.rs:LL:CC
    |
 LL |             a16.store(1, Ordering::SeqCst);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: overlapping unsynchronized atomic accesses must use the same access size
    = 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
    = note: BACKTRACE (of the first span):

tests/fail/data_race/read_read_race1.rs

@@ -21,7 +21,7 @@ fn main() {
             unsafe { ptr.read() };
             // Then do the atomic access.
             a.load(Ordering::SeqCst);
-            //~^ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>`
+            //~^ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic load on thread `<unnamed>`
         });
     });
 }

tests/fail/data_race/read_read_race1.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/read_read_race1.rs:LL:CC
    |
 LL |             a.load(Ordering::SeqCst);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/read_read_race1.rs:LL:CC
    |
 LL |             unsafe { ptr.read() };
    |                      ^^^^^^^^^^
+   = help: overlapping atomic and non-atomic accesses must be synchronized, even if both are read-only
    = 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
    = note: BACKTRACE (of the first span):

tests/fail/data_race/read_read_race2.rs

@@ -21,7 +21,7 @@ fn main() {
 
             let ptr = &a as *const AtomicU16 as *mut u16;
             unsafe { ptr.read() };
-            //~^ ERROR: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+            //~^ ERROR: Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
         });
     });
 }

tests/fail/data_race/read_read_race2.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/read_read_race2.rs:LL:CC
    |
 LL |             unsafe { ptr.read() };
-   |                      ^^^^^^^^^^ Data race detected between (1) Atomic Load on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                      ^^^^^^^^^^ Data race detected between (1) atomic load on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/read_read_race2.rs:LL:CC
    |
 LL |             a.load(Ordering::SeqCst);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: overlapping atomic and non-atomic accesses must be synchronized, even if both are read-only
    = 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
    = note: BACKTRACE (of the first span):

tests/fail/data_race/read_write_race.rs

@@ -21,7 +21,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            *c.0 = 64; //~ ERROR: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/read_write_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/read_write_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/read_write_race.rs:LL:CC

tests/fail/data_race/read_write_race_stack.rs

@@ -40,7 +40,7 @@ pub fn main() {
 
             sleep(Duration::from_millis(200));
 
-            stack_var //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+            stack_var //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
         });
 
         let j2 = spawn(move || {

tests/fail/data_race/read_write_race_stack.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/read_write_race_stack.rs:LL:CC
    |
 LL |             stack_var
-   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/read_write_race_stack.rs:LL:CC

tests/fail/data_race/relax_acquire_race.rs

@@ -39,7 +39,7 @@ pub fn main() {
         let j3 = spawn(move || {
             let c = c; // avoid field capturing
             if SYNC.load(Ordering::Acquire) == 2 {
-                *c.0 //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
             } else {
                 0
             }

tests/fail/data_race/relax_acquire_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/relax_acquire_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                 ^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/relax_acquire_race.rs:LL:CC

tests/fail/data_race/release_seq_race.rs

@@ -43,7 +43,7 @@ pub fn main() {
             let c = c; // avoid field capturing
             sleep(Duration::from_millis(500));
             if SYNC.load(Ordering::Acquire) == 3 {
-                *c.0 //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
             } else {
                 0
             }

tests/fail/data_race/release_seq_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/release_seq_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                 ^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/release_seq_race.rs:LL:CC

tests/fail/data_race/release_seq_race_same_thread.rs

@@ -39,7 +39,7 @@ pub fn main() {
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
             if SYNC.load(Ordering::Acquire) == 2 {
-                *c.0 //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
             } else {
                 0
             }

tests/fail/data_race/release_seq_race_same_thread.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/release_seq_race_same_thread.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                 ^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/release_seq_race_same_thread.rs:LL:CC

tests/fail/data_race/rmw_race.rs

@@ -40,7 +40,7 @@ pub fn main() {
         let j3 = spawn(move || {
             let c = c; // capture `c`, not just its field.
             if SYNC.load(Ordering::Acquire) == 3 {
-                *c.0 //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>`
+                *c.0 //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>`
             } else {
                 0
             }

tests/fail/data_race/rmw_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/rmw_race.rs:LL:CC
    |
 LL |                 *c.0
-   |                 ^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Read on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                 ^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic read on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/rmw_race.rs:LL:CC

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 (1) Read on thread `<unnamed>` and (2) Deallocate on thread `main`
+} //~ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `main`

tests/fail/data_race/stack_pop_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `main` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `main` at ALLOC. (2) just happened here
   --> $DIR/stack_pop_race.rs:LL:CC
    |
 LL | }
-   |  ^ Data race detected between (1) Read on thread `<unnamed>` and (2) Deallocate on thread `main` at ALLOC. (2) just happened here
+   |  ^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) deallocation on thread `main` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/stack_pop_race.rs:LL:CC

tests/fail/data_race/write_write_race.rs

@@ -21,7 +21,7 @@ pub fn main() {
 
         let j2 = spawn(move || {
             let c = c; // avoid field capturing
-            *c.0 = 64; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            *c.0 = 64; //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
         });
 
         j1.join().unwrap();

tests/fail/data_race/write_write_race.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/write_write_race.rs:LL:CC
    |
 LL |             *c.0 = 64;
-   |             ^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/write_write_race.rs:LL:CC

tests/fail/data_race/write_write_race_stack.rs

@@ -40,7 +40,7 @@ pub fn main() {
 
             sleep(Duration::from_millis(200));
 
-            stack_var = 1usize; //~ ERROR: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+            stack_var = 1usize; //~ ERROR: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
 
             // read to silence errors
             stack_var

tests/fail/data_race/write_write_race_stack.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/write_write_race_stack.rs:LL:CC
    |
 LL |             stack_var = 1usize;
-   |             ^^^^^^^^^^^^^^^^^^ Data race detected between (1) Write on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic write on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/write_write_race_stack.rs:LL:CC

tests/fail/stacked_borrows/retag_data_race_protected_read.rs

@@ -13,7 +13,7 @@ fn main() {
         let ptr = ptr;
         // We do a protected mutable retag (but no write!) in this thread.
         fn retag(_x: &mut i32) {}
-        retag(unsafe { &mut *ptr.0 }); //~ERROR: Data race detected between (1) Read on thread `main` and (2) Write on thread `<unnamed>`
+        retag(unsafe { &mut *ptr.0 }); //~ERROR: Data race detected between (1) non-atomic read on thread `main` and (2) non-atomic write on thread `<unnamed>`
     });
 
     // We do a read in the main thread.

tests/fail/stacked_borrows/retag_data_race_protected_read.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `main` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/retag_data_race_protected_read.rs:LL:CC
    |
 LL |         retag(unsafe { &mut *ptr.0 });
-   |                        ^^^^^^^^^^^ Data race detected between (1) Read on thread `main` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |                        ^^^^^^^^^^^ Data race detected between (1) non-atomic read on thread `main` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/retag_data_race_protected_read.rs:LL:CC

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 (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>`
+        *p = 5; //~ ERROR: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>`
     }
 }
 

tests/fail/stacked_borrows/retag_data_race_read.stderr

@@ -1,8 +1,8 @@
-error: Undefined Behavior: Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/retag_data_race_read.rs:LL:CC
    |
 LL |         *p = 5;
-   |         ^^^^^^ Data race detected between (1) Read on thread `<unnamed>` and (2) Write on thread `<unnamed>` at ALLOC. (2) just happened here
+   |         ^^^^^^ Data race detected between (1) non-atomic read on thread `<unnamed>` and (2) non-atomic write on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/retag_data_race_read.rs:LL:CC

tests/fail/weak_memory/racing_mixed_size.rs

@@ -31,7 +31,7 @@ pub fn main() {
         let x_split = split_u32_ptr(x_ptr);
         unsafe {
             let hi = ptr::addr_of!((*x_split)[0]);
-            std::intrinsics::atomic_load_relaxed(hi); //~ ERROR: different-size
+            std::intrinsics::atomic_load_relaxed(hi); //~ ERROR: (1) 4-byte atomic store on thread `<unnamed>` and (2) 2-byte atomic load
         }
     });
 

tests/fail/weak_memory/racing_mixed_size.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Race condition detected between (1) 4-byte Atomic Store on thread `<unnamed>` and (2) 2-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Race condition detected between (1) 4-byte atomic store on thread `<unnamed>` and (2) 2-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/racing_mixed_size.rs:LL:CC
    |
 LL |             std::intrinsics::atomic_load_relaxed(hi);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 4-byte Atomic Store on thread `<unnamed>` and (2) 2-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 4-byte atomic store on thread `<unnamed>` and (2) 2-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/racing_mixed_size.rs:LL:CC
    |
 LL |         x.store(1, Relaxed);
    |         ^^^^^^^^^^^^^^^^^^^
+   = help: overlapping unsynchronized atomic accesses must use the same access size
    = 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
    = note: BACKTRACE (of the first span):

tests/fail/weak_memory/racing_mixed_size_read.rs

@@ -29,7 +29,7 @@ pub fn main() {
         let x_split = split_u32_ptr(x_ptr);
         unsafe {
             let hi = x_split as *const u16 as *const AtomicU16;
-            (*hi).load(Relaxed); //~ ERROR: different-size
+            (*hi).load(Relaxed); //~ ERROR: (1) 4-byte atomic load on thread `<unnamed>` and (2) 2-byte atomic load
         }
     });
 

tests/fail/weak_memory/racing_mixed_size_read.stderr

@@ -1,14 +1,15 @@
-error: Undefined Behavior: Race condition detected between (1) 4-byte Atomic Load on thread `<unnamed>` and (2) 2-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+error: Undefined Behavior: Race condition detected between (1) 4-byte atomic load on thread `<unnamed>` and (2) 2-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
   --> $DIR/racing_mixed_size_read.rs:LL:CC
    |
 LL |             (*hi).load(Relaxed);
-   |             ^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 4-byte Atomic Load on thread `<unnamed>` and (2) 2-byte (different-size) Atomic Load on thread `<unnamed>` at ALLOC. (2) just happened here
+   |             ^^^^^^^^^^^^^^^^^^^ Race condition detected between (1) 4-byte atomic load on thread `<unnamed>` and (2) 2-byte atomic load on thread `<unnamed>` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> $DIR/racing_mixed_size_read.rs:LL:CC
    |
 LL |         x.load(Relaxed);
    |         ^^^^^^^^^^^^^^^
+   = help: overlapping unsynchronized atomic accesses must use the same access size
    = 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
    = note: BACKTRACE (of the first span):