Print thread ID in panic message if thread name is unknown

tgross35 · tgross35 · commit 1ccd96f38efe · 2025-08-06T23:59:47.000Z
`panic!` does not print any identifying information for threads that are
unnamed. However, in many cases, the thread ID can be determined.

This changes the panic message from something like this:

    thread '&lt;unnamed&gt;' panicked at src/main.rs:3:5:
    explicit panic

To something like this:

    thread '&lt;unnamed&gt;' (0xff9bf) panicked at src/main.rs:3:5:
    explicit panic

Stack overflow messages are updated as well.

This change applies to both named and unnamed threads. The ID printed is
the OS integer thread ID rather than the Rust thread ID, which should
also be what debuggers print.
diff --git a/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr b/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind1.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/function_calls/exported_symbol_bad_unwind1.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr b/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr
@@ -1,10 +1,10 @@
 
-thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:
 thread caused non-unwinding panic. aborting.
diff --git a/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr b/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr
@@ -1,10 +1,10 @@
 
-thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:
 thread caused non-unwinding panic. aborting.
diff --git a/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr b/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/function_calls/exported_symbol_bad_unwind2.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/function_calls/return_pointer_on_unwind.stderr b/tests/fail/function_calls/return_pointer_on_unwind.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/function_calls/return_pointer_on_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/function_calls/return_pointer_on_unwind.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/abort_unwind.stderr b/tests/fail/panic/abort_unwind.stderr
@@ -1,10 +1,10 @@
 
-thread 'main' panicked at tests/fail/panic/abort_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/abort_unwind.rs:LL:CC:
 PANIC!!!
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:
 thread caused non-unwinding panic. aborting.
diff --git a/tests/fail/panic/bad_unwind.stderr b/tests/fail/panic/bad_unwind.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/panic/bad_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/bad_unwind.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/double_panic.stderr b/tests/fail/panic/double_panic.stderr
@@ -1,14 +1,14 @@
 
-thread 'main' panicked at tests/fail/panic/double_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/double_panic.rs:LL:CC:
 first
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at tests/fail/panic/double_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/double_panic.rs:LL:CC:
 second
 stack backtrace:
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a destructor during cleanup
 thread caused non-unwinding panic. aborting.
 error: abnormal termination: the program aborted execution
diff --git a/tests/fail/panic/panic_abort1.stderr b/tests/fail/panic/panic_abort1.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/panic/panic_abort1.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/panic_abort1.rs:LL:CC:
 panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/panic_abort2.stderr b/tests/fail/panic/panic_abort2.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/panic/panic_abort2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/panic_abort2.rs:LL:CC:
 42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/panic_abort3.stderr b/tests/fail/panic/panic_abort3.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/panic/panic_abort3.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/panic_abort3.rs:LL:CC:
 panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/panic_abort4.stderr b/tests/fail/panic/panic_abort4.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/panic/panic_abort4.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/panic/panic_abort4.rs:LL:CC:
 42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/fail/panic/tls_macro_const_drop_panic.stderr b/tests/fail/panic/tls_macro_const_drop_panic.stderr
@@ -1,5 +1,5 @@
 
-thread $NAME panicked at tests/fail/panic/tls_macro_const_drop_panic.rs:LL:CC:
+thread $NAME ($TID) panicked at tests/fail/panic/tls_macro_const_drop_panic.rs:LL:CC:
 ow
 fatal runtime error: thread local panicked on drop, aborting
 error: abnormal termination: the program aborted execution
diff --git a/tests/fail/panic/tls_macro_drop_panic.stderr b/tests/fail/panic/tls_macro_drop_panic.stderr
@@ -1,5 +1,5 @@
 
-thread $NAME panicked at tests/fail/panic/tls_macro_drop_panic.rs:LL:CC:
+thread $NAME ($TID) panicked at tests/fail/panic/tls_macro_drop_panic.rs:LL:CC:
 ow
 fatal runtime error: thread local panicked on drop, aborting
 error: abnormal termination: the program aborted execution
diff --git a/tests/fail/ptr_swap_nonoverlapping.stderr b/tests/fail/ptr_swap_nonoverlapping.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/fail/ptr_swap_nonoverlapping.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/ptr_swap_nonoverlapping.rs:LL:CC:
 unsafe precondition(s) violated: ptr::swap_nonoverlapping requires that both pointer arguments are aligned and non-null and the specified memory ranges do not overlap
 
 This indicates a bug in the program. This Undefined Behavior check is optional, and cannot be relied on for safety.
diff --git a/tests/fail/terminate-terminator.stderr b/tests/fail/terminate-terminator.stderr
@@ -1,12 +1,12 @@
 warning: You have explicitly enabled MIR optimizations, overriding Miri's default which is to completely disable them. Any optimizations may hide UB that Miri would otherwise detect, and it is not necessarily possible to predict what kind of UB will be missed. If you are enabling optimizations to make Miri run faster, we advise using cfg(miri) to shrink your workload instead. The performance benefit of enabling MIR optimizations is usually marginal at best.
 
 
-thread 'main' panicked at tests/fail/terminate-terminator.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/terminate-terminator.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:
 thread caused non-unwinding panic. aborting.
diff --git a/tests/fail/unwind-action-terminate.stderr b/tests/fail/unwind-action-terminate.stderr
@@ -1,10 +1,10 @@
 
-thread 'main' panicked at tests/fail/unwind-action-terminate.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/fail/unwind-action-terminate.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a function that cannot unwind
 stack backtrace:
 thread caused non-unwinding panic. aborting.
diff --git a/tests/panic/alloc_error_handler_hook.stderr b/tests/panic/alloc_error_handler_hook.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/alloc_error_handler_hook.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/alloc_error_handler_hook.rs:LL:CC:
 alloc error hook called
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/alloc_error_handler_panic.stderr b/tests/panic/alloc_error_handler_panic.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at RUSTLIB/std/src/alloc.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/std/src/alloc.rs:LL:CC:
 memory allocation of 4 bytes failed
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/div-by-zero-2.stderr b/tests/panic/div-by-zero-2.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/div-by-zero-2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/div-by-zero-2.rs:LL:CC:
 attempt to divide by zero
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/function_calls/exported_symbol_good_unwind.stderr b/tests/panic/function_calls/exported_symbol_good_unwind.stderr
@@ -1,11 +1,11 @@
 
-thread 'main' panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
 explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
 explicit panic
 
-thread 'main' panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/function_calls/exported_symbol_good_unwind.rs:LL:CC:
 explicit panic
diff --git a/tests/panic/mir-validation.rs b/tests/panic/mir-validation.rs
@@ -8,6 +8,12 @@
 // Somehow on rustc Windows CI, the "Miri caused an ICE" message is not shown
 // and we don't even get a regular panic; rustc aborts with a different exit code instead.
 //@ignore-host: windows
+
+// FIXME: this tests a crash in rustc. For stage1, rustc is built with the downloaded standard
+// library which doesn't yet print the thread ID. Normalization can be removed at the stage bump.
+// For the grep: cfg(bootstrap)
+//@normalize-stderr-test: "thread 'rustc' panicked" -> "thread 'rustc' ($$TID) panicked"
+
 #![feature(custom_mir, core_intrinsics)]
 use core::intrinsics::mir::*;
 
diff --git a/tests/panic/mir-validation.stderr b/tests/panic/mir-validation.stderr
@@ -6,7 +6,7 @@ LL |             *(tuple.0) = 1;
    |             ^^^^^^^^^^^^^^
 
 
-thread 'rustc' panicked at compiler/rustc_mir_transform/src/validate.rs:LL:CC:
+thread 'rustc' ($TID) panicked at compiler/rustc_mir_transform/src/validate.rs:LL:CC:
 Box<dyn Any>
 stack backtrace:
 
diff --git a/tests/panic/oob_subslice.stderr b/tests/panic/oob_subslice.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/oob_subslice.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/oob_subslice.rs:LL:CC:
 range end index 5 out of range for slice of length 4
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/overflowing-lsh-neg.stderr b/tests/panic/overflowing-lsh-neg.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/overflowing-lsh-neg.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/overflowing-lsh-neg.rs:LL:CC:
 attempt to shift left with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/overflowing-rsh-1.stderr b/tests/panic/overflowing-rsh-1.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/overflowing-rsh-1.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/overflowing-rsh-1.rs:LL:CC:
 attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/overflowing-rsh-2.stderr b/tests/panic/overflowing-rsh-2.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/overflowing-rsh-2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/overflowing-rsh-2.rs:LL:CC:
 attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/panic1.stderr b/tests/panic/panic1.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/panic1.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/panic1.rs:LL:CC:
 panicking from libstd
 stack backtrace:
    0: std::panicking::begin_panic_handler
diff --git a/tests/panic/panic2.stderr b/tests/panic/panic2.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/panic2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/panic2.rs:LL:CC:
 42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/panic3.stderr b/tests/panic/panic3.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/panic3.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/panic3.rs:LL:CC:
 panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/panic4.stderr b/tests/panic/panic4.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/panic4.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/panic4.rs:LL:CC:
 42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/panic/transmute_fat2.stderr b/tests/panic/transmute_fat2.stderr
@@ -1,5 +1,5 @@
 
-thread 'main' panicked at tests/panic/transmute_fat2.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/panic/transmute_fat2.rs:LL:CC:
 index out of bounds: the len is 0 but the index is 0
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/tests/pass/panic/catch_panic.stderr b/tests/pass/panic/catch_panic.stderr
@@ -1,47 +1,47 @@
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Hello from std::panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 Caught panic message (&str): Hello from std::panic
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Hello from std::panic: 1
 Caught panic message (String): Hello from std::panic: 1
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Hello from std::panic_any: 2
 Caught panic message (String): Hello from std::panic_any: 2
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Box<dyn Any>
 Failed to get caught panic message.
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Hello from core::panic
 Caught panic message (&str): Hello from core::panic
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 Hello from core::panic: 5
 Caught panic message (String): Hello from core::panic: 5
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 index out of bounds: the len is 3 but the index is 4
 Caught panic message (String): index out of bounds: the len is 3 but the index is 4
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 attempt to divide by zero
 Caught panic message (&str): attempt to divide by zero
 
-thread 'main' panicked at RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC:
+thread 'main' ($TID) panicked at RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC:
 align_offset: align is not a power-of-two
 Caught panic message (&str): align_offset: align is not a power-of-two
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 assertion failed: false
 Caught panic message (&str): assertion failed: false
 
-thread 'main' panicked at tests/pass/panic/catch_panic.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/catch_panic.rs:LL:CC:
 assertion failed: false
 Caught panic message (&str): assertion failed: false
 Success!
diff --git a/tests/pass/panic/concurrent-panic.stderr b/tests/pass/panic/concurrent-panic.stderr
@@ -1,15 +1,15 @@
 Thread 1 starting, will block on mutex
 Thread 1 reported it has started
 
-thread '<unnamed>' panicked at tests/pass/panic/concurrent-panic.rs:LL:CC:
+thread '<unnamed>' ($TID) panicked at tests/pass/panic/concurrent-panic.rs:LL:CC:
 panic in thread 2
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 Thread 2 blocking on thread 1
 Thread 2 reported it has started
 Unlocking mutex
 
-thread '<unnamed>' panicked at tests/pass/panic/concurrent-panic.rs:LL:CC:
+thread '<unnamed>' ($TID) panicked at tests/pass/panic/concurrent-panic.rs:LL:CC:
 panic in thread 1
 Thread 1 has exited
 Thread 2 has exited
diff --git a/tests/pass/panic/nested_panic_caught.stderr b/tests/pass/panic/nested_panic_caught.stderr
@@ -1,9 +1,9 @@
 
-thread 'main' panicked at tests/pass/panic/nested_panic_caught.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/nested_panic_caught.rs:LL:CC:
 once
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'main' panicked at tests/pass/panic/nested_panic_caught.rs:LL:CC:
+thread 'main' ($TID) panicked at tests/pass/panic/nested_panic_caught.rs:LL:CC:
 twice
 stack backtrace:
diff --git a/tests/pass/panic/thread_panic.stderr b/tests/pass/panic/thread_panic.stderr
@@ -1,8 +1,8 @@
 
-thread '<unnamed>' panicked at tests/pass/panic/thread_panic.rs:LL:CC:
+thread '<unnamed>' ($TID) panicked at tests/pass/panic/thread_panic.rs:LL:CC:
 Hello!
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
 
-thread 'childthread' panicked at tests/pass/panic/thread_panic.rs:LL:CC:
+thread 'childthread' ($TID) panicked at tests/pass/panic/thread_panic.rs:LL:CC:
 Hello, world!
