rust Expand free alias types when computing implied outlives-bounds

Supersedes rust-lang/rust#122340 (see lengthy discussions in comments). Follow-up to rust-lang/rust#119350.

Draft status: Need to add more tests, will do later — am at conf. Also: Needs better PR descr.

r? oli-obk

May 14 '25 14:05 fmease

The job mingw-check-tidy failed! Check out the build log: (web) (plain)

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info: removing rustup binaries
info: rustup is uninstalled
##[group]Image checksum input
mingw-check-tidy
# We use the ghcr base image because ghcr doesn't have a rate limit
# and the mingw-check-tidy job doesn't cache docker images in CI.
FROM ghcr.io/rust-lang/ubuntu:22.04

ARG DEBIAN_FRONTEND=noninteractive
RUN apt-get update && apt-get install -y --no-install-recommends \
  g++ \
---

COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
COPY host-x86_64/mingw-check/validate-error-codes.sh /scripts/

# NOTE: intentionally uses python2 for x.py so we can test it still works.
# validate-toolstate only runs in our CI, so it's ok for it to only support python3.
ENV SCRIPT TIDY_PRINT_DIFF=1 python2.7 ../x.py test \
           --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
#
# This file is autogenerated by pip-compile with Python 3.10
# by the following command:
#
#    pip-compile --allow-unsafe --generate-hashes reuse-requirements.in
---
#12 2.911 Building wheels for collected packages: reuse
#12 2.912   Building wheel for reuse (pyproject.toml): started
#12 3.131   Building wheel for reuse (pyproject.toml): finished with status 'done'
#12 3.132   Created wheel for reuse: filename=reuse-4.0.3-cp310-cp310-manylinux_2_35_x86_64.whl size=132719 sha256=d2a2565e7037ad3883fb9337653f2e25bbb588534fbef3697286cbc26d1bf634
#12 3.132   Stored in directory: /tmp/pip-ephem-wheel-cache-x_vj1gcb/wheels/3d/8d/0a/e0fc6aba4494b28a967ab5eaf951c121d9c677958714e34532
#12 3.134 Successfully built reuse
#12 3.135 Installing collected packages: boolean-py, binaryornot, tomlkit, reuse, python-debian, markupsafe, license-expression, jinja2, chardet, attrs
#12 3.537 Successfully installed attrs-23.2.0 binaryornot-0.4.4 boolean-py-4.0 chardet-5.2.0 jinja2-3.1.4 license-expression-30.3.0 markupsafe-2.1.5 python-debian-0.1.49 reuse-4.0.3 tomlkit-0.13.0
#12 3.537 WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
#12 4.092 Collecting virtualenv
#12 4.142   Downloading virtualenv-20.31.2-py3-none-any.whl (6.1 MB)
#12 4.370      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 6.1/6.1 MB 26.8 MB/s eta 0:00:00
#12 4.433 Collecting platformdirs<5,>=3.9.1
#12 4.441   Downloading platformdirs-4.3.8-py3-none-any.whl (18 kB)
#12 4.482 Collecting filelock<4,>=3.12.2
#12 4.489   Downloading filelock-3.18.0-py3-none-any.whl (16 kB)
#12 4.512 Collecting distlib<1,>=0.3.7
#12 4.519   Downloading distlib-0.3.9-py2.py3-none-any.whl (468 kB)
#12 4.530      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 469.0/469.0 KB 50.5 MB/s eta 0:00:00
#12 4.612 Installing collected packages: distlib, platformdirs, filelock, virtualenv
#12 4.804 Successfully installed distlib-0.3.9 filelock-3.18.0 platformdirs-4.3.8 virtualenv-20.31.2
#12 4.804 WARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv
#12 DONE 4.9s

#13 [7/8] COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
#13 DONE 0.0s
---
DirectMap4k:      143296 kB
DirectMap2M:     9293824 kB
DirectMap1G:     9437184 kB
##[endgroup]
Executing TIDY_PRINT_DIFF=1 python2.7 ../x.py test            --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
+ TIDY_PRINT_DIFF=1 python2.7 ../x.py test --stage 0 src/tools/tidy tidyselftest --extra-checks=py,cpp
##[group]Building bootstrap
    Finished `dev` profile [unoptimized] target(s) in 0.05s
##[endgroup]
WARN: currently no CI rustc builds have rustc debug assertions enabled. Please either set `rust.debug-assertions` to `false` if you want to use download CI rustc or set `rust.download-rustc` to `false`.
[TIMING] core::build_steps::tool::LibcxxVersionTool { target: x86_64-unknown-linux-gnu } -- 0.220
---
fmt check
fmt: checked 6014 files
tidy check
tidy: Skipping binary file check, read-only filesystem
##[error]tidy error: /checkout/tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs:3: trailing whitespace
tidy error: /checkout/tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs: too many trailing newlines (2)
removing old virtual environment
creating virtual environment at '/checkout/obj/build/venv' using 'python3.10' and 'venv'
creating virtual environment at '/checkout/obj/build/venv' using 'python3.10' and 'virtualenv'
Requirement already satisfied: pip in ./build/venv/lib/python3.10/site-packages (25.1.1)
linting python files
All checks passed!
checking python file formatting
26 files already formatted
checking C++ file formatting
some tidy checks failed
Command has failed. Rerun with -v to see more details.
Build completed unsuccessfully in 0:01:52
  local time: Wed May 14 14:34:59 UTC 2025
  network time: Wed, 14 May 2025 14:35:00 GMT
##[error]Process completed with exit code 1.
Post job cleanup.

May 14 '25 14:05 rust-log-analyzer

The job x86_64-gnu-llvm-19 failed! Check out the build log: (web) (plain)

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#18 exporting to docker image format
#18 sending tarball 20.3s done
#18 DONE 27.8s
##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-19]
[CI_JOB_NAME=x86_64-gnu-llvm-19]
debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured.
---
sccache: Listening on address 127.0.0.1:4226
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-19', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--set', 'build.print-step-timings', '--enable-verbose-tests', '--set', 'build.metrics', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--set', 'gcc.download-ci-gcc=true', '--enable-new-symbol-mangling']
configure: build.build          := x86_64-unknown-linux-gnu
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-19/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
test [ui] tests/ui/wrong-hashset-issue-42918.rs ... ok

failures:

---- [ui] tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs#print stdout ----
Saved the actual stderr to "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/lazy-type-alias/implied-outlives-bounds-1.print/implied-outlives-bounds-1.print.stderr"
diff of stderr:

1 error: rustc_outlives
-   --> $DIR/implied-outlives-bounds-1.rs:16:1
+   --> $DIR/implied-outlives-bounds-1.rs:13:1
3    |
4 LL | struct Type<'a, K, V>(&'a mut Alias<K, V>);
5    | ^^^^^^^^^^^^^^^^^^^^^

Note: some mismatched output was normalized before being compared
-   --> /checkout/tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs:13:1
+   --> $DIR/implied-outlives-bounds-1.rs:13:1
---
To only update this specific test, also pass `--test-args lazy-type-alias/implied-outlives-bounds-1.rs`

error in revision `print`: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2" "--target=x86_64-unknown-linux-gnu" "--cfg" "print" "--check-cfg" "cfg(test,FALSE,default,print)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/lazy-type-alias/implied-outlives-bounds-1.print" "-A" "unused" "-A" "internal_features" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error: rustc_outlives
##[error]  --> /checkout/tests/ui/lazy-type-alias/implied-outlives-bounds-1.rs:13:1
   |
LL | struct Type<'a, K, V>(&'a mut Alias<K, V>); //[print]~ ERROR rustc_outlives
   | ^^^^^^^^^^^^^^^^^^^^^
   |
   = note: K: 'a
   = note: V: 'a

error: aborting due to 1 previous error
------------------------------------------

May 14 '25 16:05 rust-log-analyzer