[EXPERIMENT] Introduce TypingMode::Codegen to avoid layout cycles

[cjgillot]

r? @ghost

[cjgillot]

@bors try @rust-timer queue

[rust-log-analyzer]

The job aarch64-gnu-llvm-19-1 failed! Check out the build log: (web) (plain enhanced) (plain)

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

test [crashes] tests/crashes/119783.rs ... ok
test [crashes] tests/crashes/119692.rs ... ok
test [crashes] tests/crashes/119786.rs ... ok
test [crashes] tests/crashes/119824.rs ... ok
2025-08-16T00:45:50.144316Z ERROR compiletest::runtest: fatal error, panic: "crashtest no longer crashes/triggers ICE, hooray! Please give it a meaningful name, add a doc-comment to the start of the test explaining why it exists and move it to tests/ui or wherever you see fit. Adding 'Fixes #<issueNr>' to your PR description ensures that the corresponding ticket is auto-closed upon merge. If you want to see verbose output, set `COMPILETEST_VERBOSE_CRASHES=1`."
test [crashes] tests/crashes/120016.rs ... FAILED
test [crashes] tests/crashes/120175.rs ... ok
test [crashes] tests/crashes/117696-1.rs ... ok
test [crashes] tests/crashes/120033.rs ... ok
test [crashes] tests/crashes/120254.rs ... ok
---
test [crashes] tests/crashes/137514.rs ... ok
test [crashes] tests/crashes/137468.rs ... ok
test [crashes] tests/crashes/137580.rs ... ok
test [crashes] tests/crashes/137888.rs ... ok
2025-08-16T00:45:54.222273Z ERROR compiletest::runtest: fatal error, panic: "crashtest no longer crashes/triggers ICE, hooray! Please give it a meaningful name, add a doc-comment to the start of the test explaining why it exists and move it to tests/ui or wherever you see fit. Adding 'Fixes #<issueNr>' to your PR description ensures that the corresponding ticket is auto-closed upon merge. If you want to see verbose output, set `COMPILETEST_VERBOSE_CRASHES=1`."
test [crashes] tests/crashes/137916.rs ... FAILED
test [crashes] tests/crashes/137582.rs ... ok
test [crashes] tests/crashes/138088.rs ... ok
test [crashes] tests/crashes/138009.rs ... ok
test [crashes] tests/crashes/138008.rs ... ok
---
failures:

---- [crashes] tests/crashes/120016.rs stdout ----

error: crashtest no longer crashes/triggers ICE, hooray! Please give it a meaningful name, add a doc-comment to the start of the test explaining why it exists and move it to tests/ui or wherever you see fit. Adding 'Fixes #<issueNr>' to your PR description ensures that the corresponding ticket is auto-closed upon merge. If you want to see verbose output, set `COMPILETEST_VERBOSE_CRASHES=1`.

thread '[crashes] tests/crashes/120016.rs' panicked at src/tools/compiletest/src/runtest/crashes.rs:17:18:
fatal error
stack backtrace:
   0: __rustc::rust_begin_unwind
---
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

---- [crashes] tests/crashes/137916.rs stdout ----

error: crashtest no longer crashes/triggers ICE, hooray! Please give it a meaningful name, add a doc-comment to the start of the test explaining why it exists and move it to tests/ui or wherever you see fit. Adding 'Fixes #<issueNr>' to your PR description ensures that the corresponding ticket is auto-closed upon merge. If you want to see verbose output, set `COMPILETEST_VERBOSE_CRASHES=1`.

thread '[crashes] tests/crashes/137916.rs' panicked at src/tools/compiletest/src/runtest/crashes.rs:17:18:
fatal error
stack backtrace:
   0: __rustc::rust_begin_unwind

[rust-bors]

☀️ Try build successful (CI)
Build commit: 34dd67f (34dd67f42f0f2050c773b332e2dd333618c22743, parent: cd7cbe818e4a66d46fe2df993d1b8518eba8a5cd)

[rust-timer]

Finished benchmarking commit (34dd67f): comparison URL.

Overall result: ❌ regressions - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.2%, 3.3%]	58
Regressions ❌ (secondary)	1.8%	[0.0%, 19.4%]	58
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.0%]	4
All ❌✅ (primary)	0.5%	[0.2%, 3.3%]	58

Max RSS (memory usage)

Results (primary 1.4%, secondary 4.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.7%	[0.5%, 7.3%]	17
Regressions ❌ (secondary)	5.4%	[1.2%, 12.3%]	6
Improvements ✅ (primary)	-1.3%	[-1.4%, -1.3%]	2
Improvements ✅ (secondary)	-2.3%	[-2.3%, -2.3%]	1
All ❌✅ (primary)	1.4%	[-1.4%, 7.3%]	19

Cycles

Results (primary 2.9%, secondary 4.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.9%	[2.9%, 2.9%]	1
Regressions ❌ (secondary)	5.3%	[2.1%, 12.0%]	12
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.0%	[-4.0%, -4.0%]	1
All ❌✅ (primary)	2.9%	[2.9%, 2.9%]	1

Binary size

Results (primary 0.1%, secondary -1.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.4%	[0.1%, 0.6%]	2
Regressions ❌ (secondary)	0.3%	[0.1%, 0.4%]	3
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	3
Improvements ✅ (secondary)	-1.8%	[-7.1%, -0.1%]	5
All ❌✅ (primary)	0.1%	[-0.0%, 0.6%]	5

Bootstrap: 469.562s -> 472.464s (0.62%)
Artifact size: 377.55 MiB -> 377.67 MiB (0.03%)