diff --git a/library/core/src/panic/panic_info.rs b/library/core/src/panic/panic_info.rs index c77e9675a6ac5..403262212580c 100644 --- a/library/core/src/panic/panic_info.rs +++ b/library/core/src/panic/panic_info.rs @@ -161,11 +161,12 @@ impl fmt::Display for PanicInfo<'_> { fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { formatter.write_str("panicked at ")?; self.location.fmt(formatter)?; + formatter.write_str(":")?; if let Some(message) = self.message { - formatter.write_str(":\n")?; + formatter.write_str("\n")?; formatter.write_fmt(*message)?; } else if let Some(payload) = self.payload.downcast_ref::<&'static str>() { - formatter.write_str(":\n")?; + formatter.write_str("\n")?; formatter.write_str(payload)?; } // NOTE: we cannot use downcast_ref::() here diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs index 464a46264cbdd..6121eaf86ce6f 100644 --- a/library/std/src/panicking.rs +++ b/library/std/src/panicking.rs @@ -746,7 +746,13 @@ fn rust_panic_with_hook( panic_count::MustAbort::PanicInHook => { // Don't try to print the message in this case // - perhaps that is causing the recursive panics. - rtprintpanic!("thread panicked while processing panic. aborting.\n"); + let panicinfo = PanicInfo::internal_constructor( + None, // no message + location, // but we want to show the location! + can_unwind, + force_no_backtrace, + ); + rtprintpanic!("{panicinfo}\nthread panicked while processing panic. aborting.\n"); } panic_count::MustAbort::AlwaysAbort => { // Unfortunately, this does not print a backtrace, because creating diff --git a/tests/ui/panics/panic-in-message-fmt.rs b/tests/ui/panics/panic-in-message-fmt.rs new file mode 100644 index 0000000000000..e5bedf96b3572 --- /dev/null +++ b/tests/ui/panics/panic-in-message-fmt.rs @@ -0,0 +1,25 @@ +// Checks what happens when formatting the panic message panics. + +//@ run-fail +//@ exec-env:RUST_BACKTRACE=0 +//@ check-run-results +//@ error-pattern: panicked while processing panic +//@ normalize-stderr-test: "\n +[0-9]+:[^\n]+" -> "" +//@ normalize-stderr-test: "\n +at [^\n]+" -> "" +//@ normalize-stderr-test: "(core/src/panicking\.rs):[0-9]+:[0-9]+" -> "$1:$$LINE:$$COL" +//@ ignore-emscripten "RuntimeError" junk in output + +use std::fmt::{Display, self}; + +struct MyStruct; + +impl Display for MyStruct { + fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result { + todo!() + } +} + +fn main() { + let instance = MyStruct; + panic!("this is wrong: {}", instance); +} diff --git a/tests/ui/panics/panic-in-message-fmt.run.stderr b/tests/ui/panics/panic-in-message-fmt.run.stderr new file mode 100644 index 0000000000000..c3a5733c8ae3f --- /dev/null +++ b/tests/ui/panics/panic-in-message-fmt.run.stderr @@ -0,0 +1,2 @@ +panicked at $DIR/panic-in-message-fmt.rs:18:9: +thread panicked while processing panic. aborting.