Auto merge of #112849 - m-ou-se:panic-message-format, r=thomcc

Change default panic handler message format.

This changes the default panic hook's message format from:

```
thread '{thread}' panicked at '{message}', {location}
```

to

```
thread '{thread}' panicked at {location}:
{message}
```

This puts the message on its own line without surrounding quotes, making it easiser to read. For example:

Before:
```
thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`', src/main.rs:4:6
```
After:
```
thread 'main' panicked at src/main.rs:4:6:
env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`
```

---

See this PR by `@nyurik,` which does that for only multi-line messages (specifically because of `assert_eq`): https://github.com/rust-lang/rust/pull/111071

This is the change that does that for *all* panic messages.

library/core/src/error.md

@@ -93,7 +93,8 @@ information that is already communicated by the source error being
 unwrapped:
 
 ```text
-thread 'main' panicked at 'env variable `IMPORTANT_PATH` is not set: NotPresent', src/main.rs:4:6
+thread 'main' panicked at src/main.rs:4:6:
+env variable `IMPORTANT_PATH` is not set: NotPresent
 ```
 
 In this example we end up mentioning that an env variable is not set,
@@ -109,7 +110,8 @@ prevent the source error, we end up introducing new information that is
 independent from our source error.
 
 ```text
-thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`: NotPresent', src/main.rs:4:6
+thread 'main' panicked at src/main.rs:4:6:
+env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`: NotPresent
 ```
 
 In this example we are communicating not only the name of the

library/core/src/panic/panic_info.rs

@@ -147,16 +147,18 @@ impl<'a> PanicInfo<'a> {
 impl fmt::Display for PanicInfo<'_> {
     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         formatter.write_str("panicked at ")?;
+        self.location.fmt(formatter)?;
         if let Some(message) = self.message {
-            write!(formatter, "'{}', ", message)?
+            formatter.write_str(":\n")?;
+            formatter.write_fmt(*message)?;
         } else if let Some(payload) = self.payload.downcast_ref::<&'static str>() {
-            write!(formatter, "'{}', ", payload)?
+            formatter.write_str(":\n")?;
+            formatter.write_str(payload)?;
         }
         // NOTE: we cannot use downcast_ref::<String>() here
         // since String is not available in core!
         // The payload is a String when `std::panic!` is called with multiple arguments,
         // but in that case the message is also available.
-
-        self.location.fmt(formatter)
+        Ok(())
     }
 }

library/std/src/error.rs

@@ -121,7 +121,8 @@ mod private {
 /// This example produces the following output:
 ///
 /// ```console
-/// thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: SuperError is here!: SuperErrorSideKick is here!', src/error.rs:34:40
+/// thread 'main' panicked at src/error.rs:34:40:
+/// called `Result::unwrap()` on an `Err` value: SuperError is here!: SuperErrorSideKick is here!
 /// note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 /// ```
 ///

library/std/src/panicking.rs

@@ -266,7 +266,7 @@ pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path
     let name = thread.as_ref().and_then(|t| t.name()).unwrap_or("<unnamed>");
 
     let write = |err: &mut dyn crate::io::Write, backtrace: Option<BacktraceStyle>| {
-        let _ = writeln!(err, "thread '{name}' panicked at '{msg}', {location}");
+        let _ = writeln!(err, "thread '{name}' panicked at {location}:\n{msg}");
 
         static FIRST_PANIC: AtomicBool = AtomicBool::new(true);
 

src/tools/miri/tests/fail/concurrency/unwind_top_of_stack.stderr

@@ -1,4 +1,5 @@
-thread '<unnamed>' panicked at 'explicit panic', $DIR/unwind_top_of_stack.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/unwind_top_of_stack.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past the topmost frame of the stack
   --> $DIR/unwind_top_of_stack.rs:LL:CC

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind1.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind1.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/exported_symbol_bad_unwind1.rs:LL:CC

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

src/tools/miri/tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

src/tools/miri/tests/fail/panic/bad_unwind.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/bad_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/bad_unwind.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/bad_unwind.rs:LL:CC

src/tools/miri/tests/fail/panic/double_panic.stderr

@@ -1,6 +1,8 @@
-thread 'main' panicked at 'first', $DIR/double_panic.rs:LL:CC
+thread 'main' panicked at $DIR/double_panic.rs:LL:CC:
+first
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'second', $DIR/double_panic.rs:LL:CC
+thread 'main' panicked at $DIR/double_panic.rs:LL:CC:
+second
 stack backtrace:
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/double_panic.rs:LL:CC

src/tools/miri/tests/fail/panic/no_std.stderr

@@ -1,4 +1,5 @@
-panicked at 'blarg I am dead', $DIR/no_std.rs:LL:CC
+panicked at $DIR/no_std.rs:LL:CC:
+blarg I am dead
 error: abnormal termination: the program aborted execution
   --> $DIR/no_std.rs:LL:CC
    |

src/tools/miri/tests/fail/panic/panic_abort1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libstd', $DIR/panic_abort1.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort1.rs:LL:CC:
+panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

src/tools/miri/tests/fail/panic/panic_abort2.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at '42-panicking from libstd', $DIR/panic_abort2.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort2.rs:LL:CC:
+42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

src/tools/miri/tests/fail/panic/panic_abort3.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libcore', $DIR/panic_abort3.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort3.rs:LL:CC:
+panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

src/tools/miri/tests/fail/panic/panic_abort4.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at '42-panicking from libcore', $DIR/panic_abort4.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort4.rs:LL:CC:
+42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

src/tools/miri/tests/fail/panic/thread_local_const_drop_panic.stderr

@@ -1,4 +1,5 @@
-thread $NAME panicked at 'ow', $DIR/thread_local_const_drop_panic.rs:LL:CC
+thread $NAME panicked at $DIR/thread_local_const_drop_panic.rs:LL:CC:
+ow
 fatal runtime error: thread local panicked on drop
 error: abnormal termination: the program aborted execution
 

src/tools/miri/tests/fail/panic/thread_local_drop_panic.stderr

@@ -1,4 +1,5 @@
-thread $NAME panicked at 'ow', $DIR/thread_local_drop_panic.rs:LL:CC
+thread $NAME panicked at $DIR/thread_local_drop_panic.rs:LL:CC:
+ow
 fatal runtime error: thread local panicked on drop
 error: abnormal termination: the program aborted execution
 

src/tools/miri/tests/fail/terminate-terminator.stderr

@@ -1,6 +1,7 @@
 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 'explicit panic', $DIR/terminate-terminator.rs:LL:CC
+thread 'main' panicked at $DIR/terminate-terminator.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/terminate-terminator.rs:LL:CC

src/tools/miri/tests/fail/unwind-action-terminate.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/unwind-action-terminate.rs:LL:CC
+thread 'main' panicked at $DIR/unwind-action-terminate.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/unwind-action-terminate.rs:LL:CC

src/tools/miri/tests/panic/div-by-zero-2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to divide by zero', $DIR/div-by-zero-2.rs:LL:CC
+thread 'main' panicked at $DIR/div-by-zero-2.rs:LL:CC:
+attempt to divide by zero
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/function_calls/exported_symbol_good_unwind.stderr

@@ -1,4 +1,7 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic

src/tools/miri/tests/panic/oob_subslice.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'range end index 5 out of range for slice of length 4', $DIR/oob_subslice.rs:LL:CC
+thread 'main' panicked at $DIR/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

src/tools/miri/tests/panic/overflowing-lsh-neg.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift left with overflow', $DIR/overflowing-lsh-neg.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-lsh-neg.rs:LL:CC:
+attempt to shift left with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/overflowing-rsh-1.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-1.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-rsh-1.rs:LL:CC:
+attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/overflowing-rsh-2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-2.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-rsh-2.rs:LL:CC:
+attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/panic1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libstd', $DIR/panic1.rs:LL:CC
+thread 'main' panicked at $DIR/panic1.rs:LL:CC:
+panicking from libstd
 stack backtrace:
    0: std::panicking::begin_panic_handler
  at RUSTLIB/std/src/panicking.rs:LL:CC

src/tools/miri/tests/panic/panic2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at '42-panicking from libstd', $DIR/panic2.rs:LL:CC
+thread 'main' panicked at $DIR/panic2.rs:LL:CC:
+42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/panic3.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'panicking from libcore', $DIR/panic3.rs:LL:CC
+thread 'main' panicked at $DIR/panic3.rs:LL:CC:
+panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/panic4.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at '42-panicking from libcore', $DIR/panic4.rs:LL:CC
+thread 'main' panicked at $DIR/panic4.rs:LL:CC:
+42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/transmute_fat2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', $DIR/transmute_fat2.rs:LL:CC
+thread 'main' panicked at $DIR/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

src/tools/miri/tests/panic/unsupported_foreign_function.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'unsupported Miri functionality: can't call foreign function `foo` on $OS', $DIR/unsupported_foreign_function.rs:LL:CC
+thread 'main' panicked at $DIR/unsupported_foreign_function.rs:LL:CC:
+unsupported Miri functionality: can't call foreign function `foo` on $OS
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/panic/unsupported_syscall.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'unsupported Miri functionality: can't execute syscall with ID 0', $DIR/unsupported_syscall.rs:LL:CC
+thread 'main' panicked at $DIR/unsupported_syscall.rs:LL:CC:
+unsupported Miri functionality: can't execute syscall with ID 0
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

src/tools/miri/tests/pass/concurrency/simple.stderr

@@ -1,3 +1,5 @@
-thread '<unnamed>' panicked at 'Hello!', $DIR/simple.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/simple.rs:LL:CC:
+Hello!
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'childthread' panicked at 'Hello, world!', $DIR/simple.rs:LL:CC
+thread 'childthread' panicked at $DIR/simple.rs:LL:CC:
+Hello, world!

src/tools/miri/tests/pass/panic/catch_panic.stderr

@@ -1,24 +1,35 @@
-thread 'main' panicked at 'Hello from panic: std', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: std
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 Caught panic message (&str): Hello from panic: std
-thread 'main' panicked at 'Hello from panic: 1', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 1
 Caught panic message (String): Hello from panic: 1
-thread 'main' panicked at 'Hello from panic: 2', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 2
 Caught panic message (String): Hello from panic: 2
-thread 'main' panicked at 'Box<dyn Any>', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Box<dyn Any>
 Failed to get caught panic message.
-thread 'main' panicked at 'Hello from panic: core', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: core
 Caught panic message (&str): Hello from panic: core
-thread 'main' panicked at 'Hello from panic: 5', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 5
 Caught panic message (String): Hello from panic: 5
-thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 4', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/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 'attempt to divide by zero', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+attempt to divide by zero
 Caught panic message (&str): attempt to divide by zero
-thread 'main' panicked at 'align_offset: align is not a power-of-two', RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC
+thread 'main' 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 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+assertion failed: false
 Caught panic message (&str): assertion failed: false
-thread 'main' panicked at 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+assertion failed: false
 Caught panic message (&str): assertion failed: false
 Success!

src/tools/miri/tests/pass/panic/concurrent-panic.stderr

@@ -1,10 +1,12 @@
 Thread 1 starting, will block on mutex
 Thread 1 reported it has started
-thread '<unnamed>' panicked at 'panic in thread 2', $DIR/concurrent-panic.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/concurrent-panic.rs:LL:CC:
+panic in thread 2
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 Thread 2 blocking on thread 1
 Thread 2 reported it has started
 Unlocking mutex
-thread '<unnamed>' panicked at 'panic in thread 1', $DIR/concurrent-panic.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/concurrent-panic.rs:LL:CC:
+panic in thread 1
 Thread 1 has exited
 Thread 2 has exited

src/tools/miri/tests/pass/panic/nested_panic_caught.stderr

@@ -1,4 +1,6 @@
-thread 'main' panicked at 'once', $DIR/nested_panic_caught.rs:LL:CC
+thread 'main' panicked at $DIR/nested_panic_caught.rs:LL:CC:
+once
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'twice', $DIR/nested_panic_caught.rs:LL:CC
+thread 'main' panicked at $DIR/nested_panic_caught.rs:LL:CC:
+twice
 stack backtrace:

tests/run-make/libtest-json/output-default.json

@@ -2,7 +2,7 @@
 { "type": "test", "event": "started", "name": "a" }
 { "type": "test", "name": "a", "event": "ok" }
 { "type": "test", "event": "started", "name": "b" }
-{ "type": "test", "name": "b", "event": "failed", "stdout": "thread 'b' panicked at 'assertion failed: false', f.rs:9:5\nnote: run with `RUST_BACKTRACE=1` environment variable to display a backtrace\n" }
+{ "type": "test", "name": "b", "event": "failed", "stdout": "thread 'b' panicked at f.rs:9:5:\nassertion failed: false\nnote: run with `RUST_BACKTRACE=1` environment variable to display a backtrace\n" }
 { "type": "test", "event": "started", "name": "c" }
 { "type": "test", "name": "c", "event": "ok" }
 { "type": "test", "event": "started", "name": "d" }

tests/run-make/libtest-json/output-stdout-success.json

@@ -2,9 +2,9 @@
 { "type": "test", "event": "started", "name": "a" }
 { "type": "test", "name": "a", "event": "ok", "stdout": "print from successful test\n" }
 { "type": "test", "event": "started", "name": "b" }
-{ "type": "test", "name": "b", "event": "failed", "stdout": "thread 'b' panicked at 'assertion failed: false', f.rs:9:5\nnote: run with `RUST_BACKTRACE=1` environment variable to display a backtrace\n" }
+{ "type": "test", "name": "b", "event": "failed", "stdout": "thread 'b' panicked at f.rs:9:5:\nassertion failed: false\nnote: run with `RUST_BACKTRACE=1` environment variable to display a backtrace\n" }
 { "type": "test", "event": "started", "name": "c" }
-{ "type": "test", "name": "c", "event": "ok", "stdout": "thread 'c' panicked at 'assertion failed: false', f.rs:15:5\n" }
+{ "type": "test", "name": "c", "event": "ok", "stdout": "thread 'c' panicked at f.rs:15:5:\nassertion failed: false\n" }
 { "type": "test", "event": "started", "name": "d" }
 { "type": "test", "name": "d", "event": "ignored", "message": "msg" }
 { "type": "suite", "event": "failed", "passed": 2, "failed": 1, "ignored": 1, "measured": 0, "filtered_out": 0, "exec_time": $TIME }

tests/run-make/libtest-junit/output-default.xml

@@ -1 +1 @@
-<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="1" tests="4" skipped="1" ><testcase classname="unknown" name="a" time="$TIME"/><testcase classname="unknown" name="b" time="$TIME"><failure type="assert"/><system-out><![CDATA[print from failing test]]>&#xA;<![CDATA[thread 'b' panicked at 'assertion failed: false', f.rs:10:5]]>&#xA;<![CDATA[note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="c" time="$TIME"/><system-out/><system-err/></testsuite></testsuites>
+<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="1" tests="4" skipped="1" ><testcase classname="unknown" name="a" time="$TIME"/><testcase classname="unknown" name="b" time="$TIME"><failure type="assert"/><system-out><![CDATA[print from failing test]]>&#xA;<![CDATA[thread 'b' panicked at f.rs:10:5:]]>&#xA;<![CDATA[assertion failed: false]]>&#xA;<![CDATA[note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="c" time="$TIME"/><system-out/><system-err/></testsuite></testsuites>

tests/run-make/libtest-junit/output-stdout-success.xml

@@ -1 +1 @@
-<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="1" tests="4" skipped="1" ><testcase classname="unknown" name="a" time="$TIME"><system-out><![CDATA[print from successful test]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="b" time="$TIME"><failure type="assert"/><system-out><![CDATA[print from failing test]]>&#xA;<![CDATA[thread 'b' panicked at 'assertion failed: false', f.rs:10:5]]>&#xA;<![CDATA[note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="c" time="$TIME"><system-out><![CDATA[thread 'c' panicked at 'assertion failed: false', f.rs:16:5]]>&#xA;<![CDATA[]]></system-out></testcase><system-out/><system-err/></testsuite></testsuites>
+<?xml version="1.0" encoding="UTF-8"?><testsuites><testsuite name="test" package="test" id="0" errors="0" failures="1" tests="4" skipped="1" ><testcase classname="unknown" name="a" time="$TIME"><system-out><![CDATA[print from successful test]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="b" time="$TIME"><failure type="assert"/><system-out><![CDATA[print from failing test]]>&#xA;<![CDATA[thread 'b' panicked at f.rs:10:5:]]>&#xA;<![CDATA[assertion failed: false]]>&#xA;<![CDATA[note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace]]>&#xA;<![CDATA[]]></system-out></testcase><testcase classname="unknown" name="c" time="$TIME"><system-out><![CDATA[thread 'c' panicked at f.rs:16:5:]]>&#xA;<![CDATA[assertion failed: false]]>&#xA;<![CDATA[]]></system-out></testcase><system-out/><system-err/></testsuite></testsuites>

tests/rustdoc-ui/doctest/failed-doctest-output-windows.stdout

@@ -26,7 +26,8 @@ stdout 2
 stderr:
 stderr 1
 stderr 2
-thread 'main' panicked at 'oh no', $DIR/failed-doctest-output-windows.rs:7:1
+thread 'main' panicked at $DIR/failed-doctest-output-windows.rs:7:1:
+oh no
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 

tests/rustdoc-ui/doctest/failed-doctest-output.stdout

@@ -26,7 +26,8 @@ stdout 2
 stderr:
 stderr 1
 stderr 2
-thread 'main' panicked at 'oh no', $DIR/failed-doctest-output.rs:7:1
+thread 'main' panicked at $DIR/failed-doctest-output.rs:7:1:
+oh no
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 
 

tests/rustdoc-ui/ice-bug-report-url.rs

@@ -6,7 +6,7 @@
 
 // normalize-stderr-test "note: compiler flags.*\n\n" -> ""
 // normalize-stderr-test "note: rustc.*running on.*" -> "note: rustc {version} running on {platform}"
-// normalize-stderr-test "thread.*panicked at .*, compiler.*" -> "thread panicked at 'aborting due to `-Z treat-err-as-bug`'"
+// normalize-stderr-test "thread.*panicked at compiler.*" -> ""
 // normalize-stderr-test " +\d{1,}: .*\n" -> ""
 // normalize-stderr-test " + at .*\n" -> ""
 // normalize-stderr-test ".*note: Some details are omitted.*\n" -> ""

tests/rustdoc-ui/ice-bug-report-url.stderr

@@ -4,7 +4,8 @@ error: expected one of `->`, `where`, or `{`, found `<eof>`
 LL | fn wrong()
    |          ^ expected one of `->`, `where`, or `{`
 
-thread panicked at 'aborting due to `-Z treat-err-as-bug`'
+
+aborting due to `-Z treat-err-as-bug=1`
 stack backtrace:
 
 error: the compiler unexpectedly panicked. this is a bug.

tests/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-completion.rs

@@ -2,7 +2,8 @@
 // be talking about `async fn`s instead.
 
 // run-fail
-// error-pattern: thread 'main' panicked at '`async fn` resumed after completion'
+// error-pattern: thread 'main' panicked
+// error-pattern: `async fn` resumed after completion
 // edition:2018
 // ignore-wasm no panic or subprocess support
 // ignore-emscripten no panic or subprocess support

tests/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs

@@ -3,7 +3,8 @@
 
 // run-fail
 // needs-unwind
-// error-pattern: thread 'main' panicked at '`async fn` resumed after panicking'
+// error-pattern: thread 'main' panicked
+// error-pattern: `async fn` resumed after panicking
 // edition:2018
 // ignore-wasm no panic or subprocess support
 

tests/ui/const-generics/late-bound-vars/in_closure.rs

@@ -8,7 +8,7 @@
 // normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
 // normalize-stderr-test "note: compiler flags.*\n\n" -> ""
 // normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "thread.*panicked.*\n" -> ""
+// normalize-stderr-test "thread.*panicked.*:\n.*\n" -> ""
 // normalize-stderr-test "stack backtrace:\n" -> ""
 // normalize-stderr-test "\s\d{1,}: .*\n" -> ""
 // normalize-stderr-test "\s at .*\n" -> ""

tests/ui/const-generics/late-bound-vars/simple.rs

@@ -8,7 +8,7 @@
 // normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
 // normalize-stderr-test "note: compiler flags.*\n\n" -> ""
 // normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "thread.*panicked.*\n" -> ""
+// normalize-stderr-test "thread.*panicked.*:\n.*\n" -> ""
 // normalize-stderr-test "stack backtrace:\n" -> ""
 // normalize-stderr-test "\s\d{1,}: .*\n" -> ""
 // normalize-stderr-test "\s at .*\n" -> ""

tests/ui/consts/const-eval/const-eval-query-stack.rs

@@ -5,7 +5,7 @@
 // normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
 // normalize-stderr-test "note: compiler flags.*\n\n" -> ""
 // normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "thread.*panicked.*\n" -> ""
+// normalize-stderr-test "thread.*panicked.*:\n.*\n" -> ""
 // normalize-stderr-test "stack backtrace:\n" -> ""
 // normalize-stderr-test "\s\d{1,}: .*\n" -> ""
 // normalize-stderr-test "\s at .*\n" -> ""

tests/ui/consts/precise-drop-with-promoted.rs

@@ -3,7 +3,7 @@
 // known-bug: #103507
 // failure-status: 101
 // normalize-stderr-test "note: .*\n\n" -> ""
-// normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
+// normalize-stderr-test "thread 'rustc' panicked.*\n.*\n" -> ""
 // normalize-stderr-test "(error: internal compiler error: [^:]+):\d+:\d+: " -> "$1:LL:CC: "
 // rustc-env:RUST_BACKTRACE=0
 

tests/ui/generic-associated-types/issue-90014-tait2.rs

@@ -11,7 +11,7 @@
 // normalize-stderr-test "note: we would appreciate a bug report.*\n\n" -> ""
 // normalize-stderr-test "note: compiler flags.*\n\n" -> ""
 // normalize-stderr-test "note: rustc.*running on.*\n\n" -> ""
-// normalize-stderr-test "thread.*panicked.*\n" -> ""
+// normalize-stderr-test "thread.*panicked.*:\n.*\n" -> ""
 // normalize-stderr-test "stack backtrace:\n" -> ""
 // normalize-stderr-test "\s\d{1,}: .*\n" -> ""
 // normalize-stderr-test "\s at .*\n" -> ""

tests/ui/higher-ranked/trait-bounds/future.rs

@@ -7,7 +7,7 @@
 //[classic] build-fail
 //[classic] failure-status: 101
 //[classic] normalize-stderr-test "note: .*\n\n" -> ""
-//[classic] normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
+//[classic] normalize-stderr-test "thread 'rustc' panicked.*\n.*\n" -> ""
 //[classic] normalize-stderr-test "(error: internal compiler error: [^:]+):\d+:\d+: " -> "$1:LL:CC: "
 //[classic] rustc-env:RUST_BACKTRACE=0
 

tests/ui/hygiene/panic-location.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'capacity overflow', library/alloc/src/raw_vec.rs:534:5
+thread 'main' panicked at library/alloc/src/raw_vec.rs:534:5:
+capacity overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/impl-trait/issues/issue-86800.rs

@@ -5,7 +5,7 @@
 // error-pattern: aborting due to `-Z treat-err-as-bug=1`
 // failure-status:101
 // normalize-stderr-test ".*note: .*\n\n" -> ""
-// normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
+// normalize-stderr-test "thread 'rustc' panicked.*:\n.*\n" -> ""
 // rustc-env:RUST_BACKTRACE=0
 
 use std::future::Future;

tests/ui/intrinsics/const-eval-select-backtrace-std.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'byte index 1 is out of bounds of ``', $DIR/const-eval-select-backtrace-std.rs:6:6
+thread 'main' panicked at $DIR/const-eval-select-backtrace-std.rs:6:6:
+byte index 1 is out of bounds of ``
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/intrinsics/const-eval-select-backtrace.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'Aaah!', $DIR/const-eval-select-backtrace.rs:17:9
+thread 'main' panicked at $DIR/const-eval-select-backtrace.rs:17:9:
+Aaah!
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/issues/issue-87707.run.stderr

@@ -1,3 +1,5 @@
-thread 'main' panicked at 'Here Once instance is poisoned.', $DIR/issue-87707.rs:14:24
+thread 'main' panicked at $DIR/issue-87707.rs:14:24:
+Here Once instance is poisoned.
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'Once instance has previously been poisoned', $DIR/issue-87707.rs:16:7
+thread 'main' panicked at $DIR/issue-87707.rs:16:7:
+Once instance has previously been poisoned

tests/ui/layout/valid_range_oob.stderr

@@ -1,3 +1,4 @@
+257 > 255
 error: the compiler unexpectedly panicked. this is a bug.
 
 query stack during panic:

tests/ui/macros/assert-eq-macro-msg.rs

@@ -1,7 +1,7 @@
 // run-fail
-// error-pattern:panicked at 'assertion failed: `(left == right)`
+// error-pattern:assertion failed: `(left == right)`
 // error-pattern: left: `2`
-// error-pattern:right: `3`: 1 + 1 definitely should be 3'
+// error-pattern:right: `3`: 1 + 1 definitely should be 3
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/macros/assert-macro-explicit.rs

@@ -1,5 +1,5 @@
 // run-fail
-// error-pattern:panicked at 'assertion failed: false'
+// error-pattern:assertion failed: false
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/macros/assert-macro-fmt.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-assert-fmt 42 rust'
+// error-pattern: panicked
+// error-pattern: test-assert-fmt 42 rust
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/macros/assert-macro-owned.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-assert-owned'
+// error-pattern:panicked
+// error-pattern:test-assert-owned
 // ignore-emscripten no processes
 
 #![allow(non_fmt_panics)]

tests/ui/macros/assert-macro-static.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-assert-static'
+// error-pattern:panicked
+// error-pattern:test-assert-static
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/macros/assert-matches-macro-msg.rs

@@ -1,7 +1,7 @@
 // run-fail
-// error-pattern:panicked at 'assertion failed: `(left matches right)`
+// error-pattern:assertion failed: `(left matches right)`
 // error-pattern: left: `2`
-// error-pattern:right: `3`: 1 + 1 definitely should be 3'
+// error-pattern:right: `3`: 1 + 1 definitely should be 3
 // ignore-emscripten no processes
 
 #![feature(assert_matches)]

tests/ui/macros/assert-ne-macro-msg.rs

@@ -1,7 +1,7 @@
 // run-fail
-// error-pattern:panicked at 'assertion failed: `(left != right)`
+// error-pattern:assertion failed: `(left != right)`
 // error-pattern: left: `2`
-// error-pattern:right: `2`: 1 + 1 definitely should not be 2'
+// error-pattern:right: `2`: 1 + 1 definitely should not be 2
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/mir/validate/storage-live.stderr

@@ -5,6 +5,7 @@ error: internal compiler error: broken MIR in Item(DefId(0:8 ~ storage_live[HASH
 LL |             StorageLive(a);
    |             ^^^^^^^^^^^^^^
 
+aborting due to `-Z treat-err-as-bug=1`
 error: the compiler unexpectedly panicked. this is a bug.
 
 query stack during panic:

tests/ui/nll/issue-51345-2.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern: thread 'main' panicked at 'explicit panic'
+// error-pattern:thread 'main' panicked
+// error-pattern:explicit panic
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/numbers-arithmetic/overflowing-add.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to add with overflow'
+// error-pattern:thread 'main' panicked
+// error-pattern:attempt to add with overflow
 // compile-flags: -C debug-assertions
 // ignore-emscripten no processes
 

tests/ui/numbers-arithmetic/overflowing-mul.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to multiply with overflow'
+// error-pattern:thread 'main' panicked
+// error-pattern:attempt to multiply with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/numbers-arithmetic/overflowing-neg-nonzero.rs

@@ -1,5 +1,5 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to negate with overflow'
+// error-pattern:attempt to negate with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/numbers-arithmetic/overflowing-neg.rs

@@ -1,5 +1,5 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to negate with overflow'
+// error-pattern:attempt to negate with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/numbers-arithmetic/overflowing-pow-signed.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to multiply with overflow'
+// error-pattern:thread 'main' panicked
+// error-pattern:attempt to multiply with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/numbers-arithmetic/overflowing-pow-unsigned.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to multiply with overflow'
+// error-pattern:thread 'main' panicked
+// error-pattern:attempt to multiply with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/numbers-arithmetic/overflowing-sub.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'attempt to subtract with overflow'
+// error-pattern:thread 'main' panicked
+// error-pattern:attempt to subtract with overflow
 // ignore-emscripten no processes
 // compile-flags: -C debug-assertions
 

tests/ui/panics/default-backtrace-ice.stderr

@@ -5,6 +5,7 @@ LL | fn main() { missing_ident; }
    |             ^^^^^^^^^^^^^ not found in this scope
 
 
+aborting due to `-Z treat-err-as-bug=1`
 stack backtrace:
 (end_short_backtrace)
 (begin_short_backtrace)

tests/ui/panics/fmt-only-once.run.stderr

@@ -1,3 +1,4 @@
 fmt
-thread 'main' panicked at 'PrintOnFmt', $DIR/fmt-only-once.rs:20:5
+thread 'main' panicked at $DIR/fmt-only-once.rs:20:5:
+PrintOnFmt
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/issue-47429-short-backtraces.legacy.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:23:5
+thread 'main' panicked at $DIR/issue-47429-short-backtraces.rs:23:5:
+explicit panic
 stack backtrace:
    0: std::panicking::begin_panic
    1: issue_47429_short_backtraces::main

tests/ui/panics/issue-47429-short-backtraces.v0.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/issue-47429-short-backtraces.rs:23:5
+thread 'main' panicked at $DIR/issue-47429-short-backtraces.rs:23:5:
+explicit panic
 stack backtrace:
    0: std::panicking::begin_panic::<&str>
    1: issue_47429_short_backtraces::main

tests/ui/panics/location-detail-panic-no-column.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'column-redacted', $DIR/location-detail-panic-no-column.rs:7:0
+thread 'main' panicked at $DIR/location-detail-panic-no-column.rs:7:0:
+column-redacted
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/location-detail-panic-no-file.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'file-redacted', <redacted>:7:5
+thread 'main' panicked at <redacted>:7:5:
+file-redacted
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/location-detail-panic-no-line.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'line-redacted', $DIR/location-detail-panic-no-line.rs:0:5
+thread 'main' panicked at $DIR/location-detail-panic-no-line.rs:0:5:
+line-redacted
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/location-detail-panic-no-location-info.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'no location info', <redacted>:0:0
+thread 'main' panicked at <redacted>:0:0:
+no location info
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/location-detail-unwrap-no-file.run.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', <redacted>:8:9
+thread 'main' panicked at <redacted>:8:9:
+called `Option::unwrap()` on a `None` value
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/ui/panics/panic-macro-any-wrapped.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'Box<dyn Any>'
+// error-pattern:panicked
+// error-pattern:Box<dyn Any>
 // ignore-emscripten no processes
 
 #![allow(non_fmt_panics)]

tests/ui/panics/panic-macro-any.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'Box<dyn Any>'
+// error-pattern:panicked
+// error-pattern:Box<dyn Any>
 // ignore-emscripten no processes
 
 #![allow(non_fmt_panics)]

tests/ui/panics/panic-macro-explicit.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'explicit panic'
+// error-pattern:panicked
+// error-pattern:explicit panic
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/panics/panic-macro-fmt.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-fail-fmt 42 rust'
+// error-pattern:panicked
+// error-pattern:test-fail-fmt 42 rust
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/panics/panic-macro-owned.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-fail-owned'
+// error-pattern:panicked
+// error-pattern:test-fail-owned
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/panics/panic-macro-static.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:panicked at 'test-fail-static'
+// error-pattern:panicked
+// error-pattern:test-fail-static
 // ignore-emscripten no processes
 
 fn main() {

tests/ui/panics/panic-set-unset-handler.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'foobar'
+// error-pattern:thread 'main' panicked
+// error-pattern:foobar
 // ignore-emscripten no processes
 
 use std::panic;

tests/ui/panics/panic-take-handler-nop.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'main' panicked at 'foobar'
+// error-pattern:thread 'main' panicked
+// error-pattern:foobar
 // ignore-emscripten no processes
 
 use std::panic;

tests/ui/panics/panic-task-name-none.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread '<unnamed>' panicked at 'test'
+// error-pattern:thread '<unnamed>' panicked
+// error-pattern:test
 // ignore-emscripten Needs threads
 
 use std::thread;

tests/ui/panics/panic-task-name-owned.rs

@@ -1,5 +1,6 @@
 // run-fail
-// error-pattern:thread 'owned name' panicked at 'test'
+// error-pattern:thread 'owned name' panicked
+// error-pattern:test
 // ignore-emscripten Needs threads.
 
 use std::thread::Builder;

tests/ui/panics/runtime-switch.legacy.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:26:5
+thread 'main' panicked at $DIR/runtime-switch.rs:26:5:
+explicit panic
 stack backtrace:
    0: std::panicking::begin_panic
    1: runtime_switch::main

tests/ui/panics/runtime-switch.v0.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/runtime-switch.rs:26:5
+thread 'main' panicked at $DIR/runtime-switch.rs:26:5:
+explicit panic
 stack backtrace:
    0: std::panicking::begin_panic::<&str>
    1: runtime_switch::main

tests/ui/panics/short-ice-remove-middle-frames-2.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'debug!!!', $DIR/short-ice-remove-middle-frames-2.rs:56:5
+thread 'main' panicked at $DIR/short-ice-remove-middle-frames-2.rs:56:5:
+debug!!!
 stack backtrace:
    0: std::panicking::begin_panic
    1: short_ice_remove_middle_frames_2::eight

tests/ui/panics/short-ice-remove-middle-frames.run.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'debug!!!', $DIR/short-ice-remove-middle-frames.rs:52:5
+thread 'main' panicked at $DIR/short-ice-remove-middle-frames.rs:52:5:
+debug!!!
 stack backtrace:
    0: std::panicking::begin_panic
    1: short_ice_remove_middle_frames::seven

tests/ui/proc-macro/load-panic-backtrace.stderr

@@ -1,4 +1,5 @@
-at 'panic-derive', $DIR/auxiliary/test-macros.rs:43:5
+at $DIR/auxiliary/test-macros.rs:43:5:
+panic-derive
 error: proc-macro derive panicked
   --> $DIR/load-panic-backtrace.rs:11:10
    |

tests/ui/process/multi-panic.rs

@@ -8,10 +8,12 @@ fn check_for_no_backtrace(test: std::process::Output) {
     let err = String::from_utf8_lossy(&test.stderr);
     let mut it = err.lines();
 
-    assert_eq!(it.next().map(|l| l.starts_with("thread '<unnamed>' panicked at")), Some(true));
+    assert_eq!(it.next().map(|l| l.starts_with("thread '<unnamed>' panicked")), Some(true));
+    assert_eq!(it.next().is_some(), true);
     assert_eq!(it.next(), Some("note: run with `RUST_BACKTRACE=1` \
                                 environment variable to display a backtrace"));
     assert_eq!(it.next().map(|l| l.starts_with("thread 'main' panicked at")), Some(true));
+    assert_eq!(it.next().is_some(), true);
     assert_eq!(it.next(), None);
 }