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

[cjgillot]

r? @ghost

[cjgillot]

@bors try @rust-timer queue

[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%)

[cjgillot]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 4e9488c (4e9488c147d4057600076145eccb670b130147d5, parent: 2e2642e641a941f0a1400c7827fd89aa86fef8f4)

[rust-timer]

Finished benchmarking commit (4e9488c): 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)	0.4%	[0.2%, 0.9%]	23
Regressions ❌ (secondary)	1.5%	[0.1%, 9.7%]	59
Improvements ✅ (primary)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	2
All ❌✅ (primary)	0.4%	[-1.6%, 0.9%]	24

Max RSS (memory usage)

Results (primary 1.7%, secondary 5.0%)

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

	mean	range	count
Regressions ❌ (primary)	1.9%	[0.5%, 7.5%]	19
Regressions ❌ (secondary)	6.6%	[0.4%, 12.9%]	5
Improvements ✅ (primary)	-1.3%	[-1.3%, -1.3%]	1
Improvements ✅ (secondary)	-2.8%	[-2.8%, -2.8%]	1
All ❌✅ (primary)	1.7%	[-1.3%, 7.5%]	20

Cycles

Results (secondary 2.7%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.2%	[2.1%, 10.2%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.8%, -2.2%]	2
All ❌✅ (primary)	-	-	0

Binary size

Results (primary 0.0%, secondary -1.1%)

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

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.1%, 0.1%]	1
Regressions ❌ (secondary)	0.2%	[0.1%, 0.4%]	4
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	3
Improvements ✅ (secondary)	-2.9%	[-6.8%, -0.0%]	3
All ❌✅ (primary)	0.0%	[-0.0%, 0.1%]	4

Bootstrap: 470.222s -> 472.094s (0.40%)
Artifact size: 377.51 MiB -> 377.42 MiB (-0.02%)

[bors]

☔ The latest upstream changes (presumably #145469) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-log-analyzer]

The job x86_64-gnu-miri failed! Check out the build log: (web) (plain enhanced) (plain)

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

tests/fail/tree_borrows/reserved/int-protected-write.rs ... ok
tests/fail/tree_borrows/reserved/cell-protected-write.rs ... ok

FAILED TEST: tests/fail/layout_cycle.rs
command: MIRI_ENV_VAR_TEST="0" MIRI_TEMP="/tmp/miri-uitest-5icGRp" RUST_BACKTRACE="1" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/miri" "--error-format=json" "--sysroot=/checkout/obj/build/x86_64-unknown-linux-gnu/miri-sysroot" "-Dwarnings" "-Dunused" "-Ainternal_features" "-Zui-testing" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/tmp/miri_ui/0/tests/fail" "tests/fail/layout_cycle.rs" "--edition" "2021"

error: actual output differed from expected
Execute `./miri test --bless` to update `tests/fail/layout_cycle.stderr` to the actual output
--- tests/fail/layout_cycle.stderr
+++ <stderr output>
 error[E0391]: cycle detected when computing layout of `S<S<()>>`
    |
    = note: ...which requires computing layout of `<S<()> as Tr>::I`...
    = note: ...which again requires computing layout of `S<S<()>>`, completing the cycle
+   = note: cycle used when computing layout of `S<S<()>>`
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
... 22 lines skipped ...
 
 For more information about this error, try `rustc --explain E0391`.

Full unnormalized output:
error[E0391]: cycle detected when computing layout of `S<S<()>>`
   |
   = note: ...which requires computing layout of `<S<()> as Tr>::I`...
   = note: ...which again requires computing layout of `S<S<()>>`, completing the cycle
   = note: cycle used when computing layout of `S<S<()>>`
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

error: post-monomorphization error: a cycle occurred during layout computation
##[error]  --> /checkout/library/core/src/mem/mod.rs:335:5
   |
LL |     intrinsics::size_of::<T>()
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ post-monomorphization error occurred here
   |
   = note: BACKTRACE:
   = note: inside `std::mem::size_of::<S<S<()>>>` at /checkout/library/core/src/mem/mod.rs:335:5: 335:31
note: inside `foo::<S<()>>`
  --> tests/fail/layout_cycle.rs:23:5
   |
LL |     mem::size_of::<S<T>>()
   |     ^^^^^^^^^^^^^^^^^^^^^^
note: inside `main`
  --> tests/fail/layout_cycle.rs:27:20
   |
LL |     println!("{}", foo::<S<()>>());
   |                    ^^^^^^^^^^^^^^

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0391`.


full stderr:
error[E0391]: cycle detected when computing layout of `S<S<()>>`
   |
   = note: ...which requires computing layout of `<S<()> as Tr>::I`...
   = note: ...which again requires computing layout of `S<S<()>>`, completing the cycle
   = note: cycle used when computing layout of `S<S<()>>`
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

error: post-monomorphization error: a cycle occurred during layout computation
##[error]  --> /checkout/library/core/src/mem/mod.rs:335:5
   |
LL |     intrinsics::size_of::<T>()
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ post-monomorphization error occurred here
   |
   = note: BACKTRACE:
   = note: inside `std::mem::size_of::<S<S<()>>>` at /checkout/library/core/src/mem/mod.rs:335:5: 335:31
note: inside `foo::<S<()>>`
  --> tests/fail/layout_cycle.rs:23:5
   |
LL |     mem::size_of::<S<T>>()
   |     ^^^^^^^^^^^^^^^^^^^^^^
note: inside `main`
  --> tests/fail/layout_cycle.rs:27:20
   |
LL |     println!("{}", foo::<S<()>>());
   |                    ^^^^^^^^^^^^^^

note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace

error: aborting due to 2 previous errors
---
Location:
   /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/ui_test-0.30.2/src/lib.rs:365

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   1: <color_eyre[cb5061225544f5ea]::config::EyreHook>::into_eyre_hook::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   2: eyre[ada77b62e15aacd9]::private::format_err<unknown>
      at <unknown source file>:<unknown line>
   3: ui_test[896b6ac6465d84c7]::run_tests_generic::<ui_test[896b6ac6465d84c7]::default_file_filter, ui[39799118c4203886]::run_tests::{closure#1}, alloc[325dcebcb1ca9745]::boxed::Box<dyn ui_test[896b6ac6465d84c7]::status_emitter::StatusEmitter>><unknown>
      at <unknown source file>:<unknown line>
   4: ui[39799118c4203886]::ui<unknown>
      at <unknown source file>:<unknown line>
   5: ui[39799118c4203886]::main<unknown>
      at <unknown source file>:<unknown line>
   6: std[dffd2cbf20fe557f]::sys::backtrace::__rust_begin_short_backtrace::<fn() -> core[7a71f79551a57e0e]::result::Result<(), eyre[ada77b62e15aacd9]::Report>, core[7a71f79551a57e0e]::result::Result<(), eyre[ada77b62e15aacd9]::Report>><unknown>
      at <unknown source file>:<unknown line>
   7: std[dffd2cbf20fe557f]::rt::lang_start::<core[7a71f79551a57e0e]::result::Result<(), eyre[ada77b62e15aacd9]::Report>>::{closure#0}<unknown>
      at <unknown source file>:<unknown line>
   8: std[dffd2cbf20fe557f]::rt::lang_start_internal<unknown>
      at <unknown source file>:<unknown line>
   9: main<unknown>
      at <unknown source file>:<unknown line>
  10: __libc_start_main<unknown>
      at <unknown source file>:<unknown line>
  11: _start<unknown>
      at <unknown source file>:<unknown line>

Run with COLORBT_SHOW_HIDDEN=1 environment variable to disable frame filtering.
Run with RUST_BACKTRACE=full to include source snippets.
error: test failed, to rerun pass `--test ui`

Caused by:
  process didn't exit successfully: `/checkout/obj/build/x86_64-unknown-linux-gnu/stage2-tools/x86_64-unknown-linux-gnu/release/deps/ui-de637b1a885c82e4` (exit status: 1)
Command `/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo test --target x86_64-unknown-linux-gnu -Zbinary-dep-depinfo -j 4 -Zroot-dir=/checkout --locked --color always --release --manifest-path /checkout/src/tools/miri/Cargo.toml -- [workdir=/checkout]` failed with exit code 1
Created at: src/bootstrap/src/core/build_steps/tool.rs:189:21
Executed at: src/bootstrap/src/core/build_steps/test.rs:644:19

Command has failed. Rerun with -v to see more details.
Bootstrap failed while executing `test --stage 2 src/tools/miri src/tools/miri/cargo-miri`
Build completed unsuccessfully in 0:46:13
  local time: Sat Aug 23 19:24:55 UTC 2025
  network time: Sat, 23 Aug 2025 19:24:55 GMT
##[error]Process completed with exit code 1.

[bors]

☔ The latest upstream changes (presumably #145384) made this pull request unmergeable. Please resolve the merge conflicts.