Warn (or error) when Self ctor from outer item is referenced in inner nested item

[compiler-errors]

This implements a warning SELF_CONSTRUCTOR_FROM_OUTER_ITEM when a self constructor from an outer impl is referenced in an inner nested item. This is a proper fix mentioned #117246 (comment).

This warning is additionally bumped to a hard error when the self type references generic parameters, since it's almost always going to ICE, and is basically never correct to do.

This also reverts part of #117246, since I believe this is the proper fix and we shouldn't need the helper functions (opt_param_at/opt_type_param) any longer, since they shouldn't really ever be used in cases where we don't have this problem.

[rustbot]

r? @Nadrieril

rustbot has assigned @Nadrieril.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[Nadrieril]

r? compiler

[compiler-errors]

anyways ill fix ci but i guess it's worth testing for regressions

@bors try

[bors]

⌛ Trying commit e26ae7b with merge 773c42f...

[bors]

☀️ Try build successful - checks-actions
Build commit: 773c42f (773c42f0166e62a538b8fa36161b0c6df69a9640)

[compiler-errors]

@craterbot check

[craterbot]

👌 Experiment pr-124187 created and queued.
🤖 Automatically detected try build 773c42f
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

[rust-timer]

Finished benchmarking commit (773c42f): comparison URL.

Overall result: ❌✅ regressions and 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)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-0.3%	[-0.3%, -0.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.3%	[-0.3%, -0.3%]	1

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)	8.5%	[8.5%, 8.5%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	8.5%	[8.5%, 8.5%]	1

Cycles

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

Binary size

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

Bootstrap: 671.572s -> 673.451s (0.28%)
Artifact size: 315.28 MiB -> 315.21 MiB (-0.02%)

[BoxyUwU]

r? compiler

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[compiler-errors]

@rustbot ready

[petrochenkov]

@bors r+

[bors]

📌 Commit a25bb5f has been approved by petrochenkov

It is now in the queue for this repository.

[bors]

⌛ Testing commit a25bb5f with merge 0958c05...

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

 mingw-w64-x86_64-gcc-ada-13.2.0-3-any downloading...
 mingw-w64-x86_64-gcc-objc-13.2.0-3-any downloading...
error: failed retrieving file 'mingw-w64-x86_64-gdb-14.1-1-any.pkg.tar.zst' from mirror.msys2.org : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
warning: too many errors from mirror.msys2.org, skipping for the remainder of this transaction
error: failed retrieving file 'mingw-w64-x86_64-gcc-objc-13.2.0-3-any.pkg.tar.zst.sig' from mirror.umd.edu : Operation too slow. Less than 1 bytes/sec transferred the last 10 seconds
error: failed to commit transaction (unexpected error)
 mingw-w64-x86_64-gcc-fortran-13.2.0-3-any downloading...
 mingw-w64-x86_64-libgccjit-13.2.0-3-any downloading...
 mingw-w64-x86_64-openssl-3.2.0-1-any downloading...

[bors]

💔 Test failed - checks-actions

[petrochenkov]

@bors retry

[bors]

⌛ Testing commit a25bb5f with merge 21e6de7...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing 21e6de7 to master...

[rust-timer]

Finished benchmarking commit (21e6de7): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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)	0.9%	[0.9%, 0.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

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

Binary size

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

Bootstrap: 672.177s -> 672.624s (0.07%)
Artifact size: 315.55 MiB -> 315.72 MiB (0.05%)