new unstable option: -Zwrite-long-types-to-disk

[mdibaiee]

This option guards the logic of writing long type names in files and instead using short forms in error messages in rustc_middle/ty/error behind a flag. The main motivation for this change is to disable this behaviour when running ui tests.

This logic can be triggered by running tests in a directory that has a long enough path, e.g. /my/very-long-path/where/rust-codebase/exists/

This means ui tests can fail depending on how long the path to their file is.

Some ui tests actually rely on this behaviour for their assertions, so for those we enable the flag manually.

[rustbot]

r? @TaKO8Ki

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[pnkfelix]

It looks like you missed updating the stderr for tests/ui/recursion/issue-83150.rs

I plan to help this PR move along by contributing patches to it (I tend to have long paths to my working directories, so landing this will help unblock my own development)

[mdibaiee]

r? @compiler-errors

[mdibaiee]

I can't figure out what the root cause of this last error I am getting is (to be fair I didn't put too much time investigating). The option I have added is untracked, but the error seems to be related to tracked options. 🤨 If someone can explain I can see about resolving it

[compiler-errors]

This looks good from the compiler side, just had one concern about UI tests:

Most of these tests don't seem to be testing long-type-names. Can you remove -Zwrite-long-types-to-disk=yes from all of them except for like long-E0308.rs, and all the other normalization stuff like

// normalize-stderr-test: "long-type-\d+" -> "long-type-hash"

and bless all the tests?

[mdibaiee]

@compiler-errors done! I initially added write-long-types-to-disk=yes to some other tests because I figured they always will produce long-enough types that would trigger the logic. I have now reverted that change and now only the test for this specific logic uses this flag.

[compiler-errors]

@bors r+

[bors]

📌 Commit b2d052b has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit b2d052b with merge bd1ae28...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing bd1ae28 to master...

[rust-timer]

Finished benchmarking commit (bd1ae28): 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)

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)	-	-	0
Improvements ✅ (secondary)	-2.0%	[-2.0%, -2.0%]	1
All ❌✅ (primary)	-	-	0

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)	-	-	0
Improvements ✅ (secondary)	-1.9%	[-1.9%, -1.9%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 650.399s -> 650.255s (-0.02%)