Simplify derive(Debug) output for fieldless enums

[clubby789]

Fixes #106875

[rustbot]

r? @michaelwoerister

(rustbot has picked a reviewer for you, use r? to override)

[saethlin]

This will get queued behind another PR but I'm quite curious
@bors try @rust-timer queue

[bors]

⌛ Trying commit 70091926e458fd7ddd3df29b33de3cfdb624c8dc with merge ab530986fdc49d3802aaf309560b6c5e75515da0...

[saethlin]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 45143c4fbec94a8323fefb0dd7a8dd5d54ede0e7 with merge 3dda7981e1a61d170870bacbe64351e30aaa3ac4...

[bors]

☀️ Try build successful - checks-actions
Build commit: 3dda7981e1a61d170870bacbe64351e30aaa3ac4 (3dda7981e1a61d170870bacbe64351e30aaa3ac4)

[rust-timer]

Finished benchmarking commit (3dda7981e1a61d170870bacbe64351e30aaa3ac4): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.7%	[0.7%, 0.7%]	1
Improvements ✅ (primary)	-0.6%	[-1.9%, -0.3%]	30
Improvements ✅ (secondary)	-1.2%	[-3.1%, -0.3%]	12
All ❌✅ (primary)	-0.6%	[-1.9%, -0.3%]	30

Max RSS (memory usage)

Results

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)	2.0%	[2.0%, 2.0%]	1
Regressions ❌ (secondary)	5.1%	[2.6%, 7.7%]	2
Improvements ✅ (primary)	-0.6%	[-0.7%, -0.5%]	3
Improvements ✅ (secondary)	-1.3%	[-1.4%, -1.2%]	5
All ❌✅ (primary)	0.1%	[-0.7%, 2.0%]	4

Cycles

Results

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
Improvements ✅ (primary)	-1.2%	[-1.2%, -1.2%]	1
Improvements ✅ (secondary)	-1.8%	[-2.6%, -1.1%]	5
All ❌✅ (primary)	-1.2%	[-1.2%, -1.2%]	1

[michaelwoerister]

Thanks for the PR, @clubby789! I'll take a closer look some time this week.

[michaelwoerister]

Thanks again for the PR, @clubby789!

It looks like the changes have the intended effect, but I think we can improve the clarity of the implementation (mostly by renaming and documenting a few things).

[michaelwoerister]

Thanks, @clubby789!

@bors r+

[bors]

📌 Commit 95a824c has been approved by michaelwoerister

It is now in the queue for this repository.

[bors]

⌛ Testing commit 95a824c with merge b22aa57...

[bors]

☀️ Test successful - checks-actions
Approved by: michaelwoerister
Pushing b22aa57 to master...

[bors]

☀️ Test successful - checks-actions
Approved by: michaelwoerister
Pushing b22aa57 to master...

[rust-timer]

Finished benchmarking commit (b22aa57): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.8%	[0.7%, 1.0%]	7
Improvements ✅ (primary)	-0.5%	[-1.7%, -0.2%]	22
Improvements ✅ (secondary)	-1.7%	[-2.9%, -0.5%]	8
All ❌✅ (primary)	-0.5%	[-1.7%, -0.2%]	22

Max RSS (memory usage)

Results

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)	5.5%	[5.5%, 5.5%]	1
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-2.9%	[-2.9%, -2.9%]	1
Improvements ✅ (secondary)	-1.1%	[-1.3%, -1.1%]	3
All ❌✅ (primary)	1.3%	[-2.9%, 5.5%]	2

Cycles

Results

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
Improvements ✅ (primary)	-1.4%	[-2.0%, -0.7%]	21
Improvements ✅ (secondary)	-2.9%	[-4.7%, -1.5%]	24
All ❌✅ (primary)	-1.4%	[-2.0%, -0.7%]	21

[therealprof]

@clubby789 Very exciting change, thank you!

[rylev]

Improvements outweigh the regressions so I think it's fine if we just take this performance as is.

@rustbot label: +perf-regression-triaged