Rollup merge of rust-lang#122930 - RalfJung:panic-in-panic-fmt, r=Amanieu

add panic location to 'panicked while processing panic'

Fixes rust-lang#97181

r? `@Amanieu`

Author: matthiaskrgr

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::<String>() here

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