Restrict #[non_exaustive] on structs with default field values

[estebank]

Do not allow users to apply #[non_exaustive] to a struct when they have also used default field values.

[rustbot]

r? @jieyouxu

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[rust-log-analyzer]

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

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

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:lint,cpp:fmt
# This file is autogenerated by pip-compile with Python 3.10
# by the following command:
#
#    pip-compile --allow-unsafe --generate-hashes reuse-requirements.in
---
#13 2.930 Building wheels for collected packages: reuse
#13 2.931   Building wheel for reuse (pyproject.toml): started
#13 3.179   Building wheel for reuse (pyproject.toml): finished with status 'done'
#13 3.180   Created wheel for reuse: filename=reuse-4.0.3-cp310-cp310-manylinux_2_35_x86_64.whl size=132720 sha256=026f3bb0f1aa8090b861fd0a0939cb1a782396d84c8aab7875096557d637a0f6
#13 3.180   Stored in directory: /tmp/pip-ephem-wheel-cache-_2qicw8m/wheels/3d/8d/0a/e0fc6aba4494b28a967ab5eaf951c121d9c677958714e34532
#13 3.183 Installing collected packages: boolean-py, binaryornot, tomlkit, reuse, python-debian, markupsafe, license-expression, jinja2, chardet, attrs
#13 3.600 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
#13 3.600 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
#13 4.132 Collecting virtualenv
#13 4.132 Collecting virtualenv
#13 4.218   Downloading virtualenv-20.28.0-py3-none-any.whl (4.3 MB)
#13 4.358      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 4.3/4.3 MB 31.0 MB/s eta 0:00:00
#13 4.416 Collecting filelock<4,>=3.12.2
#13 4.435   Downloading filelock-3.16.1-py3-none-any.whl (16 kB)
#13 4.455 Collecting distlib<1,>=0.3.7
#13 4.474   Downloading distlib-0.3.9-py2.py3-none-any.whl (468 kB)
#13 4.483      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 469.0/469.0 KB 69.5 MB/s eta 0:00:00
#13 4.518 Collecting platformdirs<5,>=3.9.1
#13 4.538   Downloading platformdirs-4.3.6-py3-none-any.whl (18 kB)
#13 4.619 Installing collected packages: distlib, platformdirs, filelock, virtualenv
#13 4.805 Successfully installed distlib-0.3.9 filelock-3.16.1 platformdirs-4.3.6 virtualenv-20.28.0
#13 DONE 4.9s

#14 [7/8] COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
#14 DONE 0.0s
---
DirectMap4k:      122816 kB
DirectMap2M:     8265728 kB
DirectMap1G:    10485760 kB
##[endgroup]
Executing TIDY_PRINT_DIFF=1 python2.7 ../x.py test            --stage 0 src/tools/tidy tidyselftest --extra-checks=py:lint,cpp:fmt
+ TIDY_PRINT_DIFF=1 python2.7 ../x.py test --stage 0 src/tools/tidy tidyselftest --extra-checks=py:lint,cpp:fmt
    Finished `dev` profile [unoptimized] target(s) in 0.04s
##[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`.
downloading https://static.rust-lang.org/dist/2024-11-27/rustfmt-nightly-x86_64-unknown-linux-gnu.tar.xz
---
fmt check
fmt: checked 5734 files
tidy check
tidy: Skipping binary file check, read-only filesystem
tidy error: /checkout/compiler/rustc_passes/messages.ftl: message `passes_should_be_applied_to_trait` is not used
removing old virtual environment
creating virtual environment at '/checkout/obj/build/venv' using 'python3.10'
Requirement already satisfied: pip in ./build/venv/lib/python3.10/site-packages (24.3.1)
All checks passed!
checking C++ file formatting
some tidy checks failed
some tidy checks failed
Command has failed. Rerun with -v to see more details.
  local time: Fri Dec 20 01:19:39 UTC 2024
  network time: Fri, 20 Dec 2024 01:19:39 GMT
##[error]Process completed with exit code 1.
Post job cleanup.