Return opaque type from PanicInfo::message()

[m-ou-se]

This changes the return type of the (unstable) PanicInfo::message() method to an opaque type (that implements Display). This allows for a bit more flexibility in the future.

See #66745

[rustbot]

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[bors]

☔ The latest upstream changes (presumably #126332) made this pull request unmergeable. Please resolve the merge conflicts.

[Amanieu]

r=me once conflicts are resolved

[m-ou-se]

@bors r=Amanieu

[bors]

📌 Commit 6c2507c has been approved by Amanieu

It is now in the queue for this repository.

[bors]

⌛ Testing commit 6c2507c with merge f873ae0...

[bors]

☀️ Test successful - checks-actions
Approved by: Amanieu
Pushing f873ae0 to master...

[rust-timer]

Finished benchmarking commit (f873ae0): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

Results (secondary 2.4%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

Results (secondary 0.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	11
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Bootstrap: 670.264s -> 670.725s (0.07%)
Artifact size: 320.46 MiB -> 320.46 MiB (-0.00%)