Modernize rustc_builtin_macros generics helpers

[dtolnay]

• Rustfmt-compatible formatting for the code snippets in comments
• Eliminate an "Extra scope required" obsoleted by NLL

[rustbot]

r? @wesleywiser

(rustbot has picked a reviewer for you, use r? to override)

[cjgillot]

For simplicity, should we directly collect into ty_param_names instead of peeking to see if empty?
r=me either way

[dtolnay]

Yes, good call. Fixed.

[dtolnay]

@bors r=cjgillot

[bors]

📌 Commit 45363f1 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit 45363f1 with merge a43b129...

[rust-log-analyzer]

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

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

   Compiling yansi v0.5.1
   Compiling diff v0.1.12
   Compiling bootstrap v0.0.0 (/checkout/src/bootstrap)
   Compiling pretty_assertions v1.4.0
error: rustc interrupted by SIGSEGV, printing backtrace

/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xb09264)[0xffffaa809264]
linux-vdso.so.1(__kernel_rt_sigreturn+0x0)[0xffffb2849598]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x28fe010)[0xffffac5fe010]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x28fe158)[0xffffac5fe158]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x3389fb4)[0xffffad089fb4]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x17b9f7c)[0xffffab4b9f7c]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x17c10fc)[0xffffab4c10fc]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0x17c1220)[0xffffab4c1220]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xd61b88)[0xffffaaa61b88]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xdb0674)[0xffffaaab0674]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xdb0a34)[0xffffaaab0a34]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xde1e10)[0xffffaaae1e10]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/librustc_driver-334d665a519da617.so(+0xdb38a0)[0xffffaaab38a0]
/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/../lib/libstd-30df84e2c5d38360.so(rust_metadata_std_e905553f7acc3271+0xb5d14)[0xffffa9c15d14]
/lib/aarch64-linux-gnu/libc.so.6(+0x7d5c8)[0xffffa9a2d5c8]
/lib/aarch64-linux-gnu/libc.so.6(+0xe5d9c)[0xffffa9a95d9c]
note: we would appreciate a report at https://github.com/rust-lang/rust
error: could not compile `bootstrap` (lib test)

Caused by:
Caused by:
  process didn't exit successfully: `/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/rustc --crate-name bootstrap --edition=2021 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --emit=dep-info,link -C embed-bitcode=no -C debuginfo=1 --test -C metadata=08c94ec9f08dd7d4 -C extra-filename=-08c94ec9f08dd7d4 --out-dir /checkout/obj/build/bootstrap/debug/deps -C incremental=/checkout/obj/build/bootstrap/debug/incremental -L dependency=/checkout/obj/build/bootstrap/debug/deps --extern build_helper=/checkout/obj/build/bootstrap/debug/deps/libbuild_helper-195e1a39d0dd96e7.rlib --extern cc=/checkout/obj/build/bootstrap/debug/deps/libcc-10a646bab1bb85f3.rlib --extern clap=/checkout/obj/build/bootstrap/debug/deps/libclap-7778f77717cfa793.rlib --extern clap_complete=/checkout/obj/build/bootstrap/debug/deps/libclap_complete-e381951bd72c94ce.rlib --extern cmake=/checkout/obj/build/bootstrap/debug/deps/libcmake-519dde474010e231.rlib --extern fd_lock=/checkout/obj/build/bootstrap/debug/deps/libfd_lock-3dd3ab9bfd14c9f5.rlib --extern filetime=/checkout/obj/build/bootstrap/debug/deps/libfiletime-134c0e0d502dc5d1.rlib --extern hex=/checkout/obj/build/bootstrap/debug/deps/libhex-ae5235553783a83c.rlib --extern ignore=/checkout/obj/build/bootstrap/debug/deps/libignore-149b2781c0d966a0.rlib --extern libc=/checkout/obj/build/bootstrap/debug/deps/liblibc-67578e8d1df3e833.rlib --extern object=/checkout/obj/build/bootstrap/debug/deps/libobject-47bb7afa69ff919c.rlib --extern once_cell=/checkout/obj/build/bootstrap/debug/deps/libonce_cell-71e537ed153aeea6.rlib --extern opener=/checkout/obj/build/bootstrap/debug/deps/libopener-6d21bb2be8e366ef.rlib --extern pretty_assertions=/checkout/obj/build/bootstrap/debug/deps/libpretty_assertions-5335b3bdd6400d0b.rlib --extern semver=/checkout/obj/build/bootstrap/debug/deps/libsemver-b0a1d00ea2a6d973.rlib --extern serde=/checkout/obj/build/bootstrap/debug/deps/libserde-6ca2be95517eec4e.rlib --extern serde_derive=/checkout/obj/build/bootstrap/debug/deps/libserde_derive-c8190b7d5ff0b840.so --extern serde_json=/checkout/obj/build/bootstrap/debug/deps/libserde_json-0a6560aa0cbdf936.rlib --extern sha2=/checkout/obj/build/bootstrap/debug/deps/libsha2-667719584ed8b7c8.rlib --extern tar=/checkout/obj/build/bootstrap/debug/deps/libtar-79f92232bbe26aac.rlib --extern termcolor=/checkout/obj/build/bootstrap/debug/deps/libtermcolor-b947e25f58e71da8.rlib --extern toml=/checkout/obj/build/bootstrap/debug/deps/libtoml-7f2208836396dcf6.rlib --extern walkdir=/checkout/obj/build/bootstrap/debug/deps/libwalkdir-6496e571e7578a52.rlib --extern xz2=/checkout/obj/build/bootstrap/debug/deps/libxz2-73cf97265753d8a7.rlib -Wrust_2018_idioms -Wunused_lifetimes -Dwarnings -L src/backend/linux_raw/arch/outline/debug -L native=/checkout/obj/build/bootstrap/debug/build/lzma-sys-e7021bfdf567ad20/out` (signal: 11, SIGSEGV: invalid memory reference)
  local time: Mon Oct 23 05:36:36 UTC 2023
  network time: Mon, 23 Oct 2023 05:36:36 GMT
##[error]Process completed with exit code 1.
Post job cleanup.

[bors]

💔 Test failed - checks-actions

[dtolnay]

@bors retry

[bors]

⌛ Testing commit 45363f1 with merge f3bfce6...

[rust-log-analyzer]

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

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

[RUSTC-TIMING] displaydoc test:false 1.817
   Compiling yoke-derive v0.7.1
[RUSTC-TIMING] aho_corasick test:false 10.989
   Compiling zerovec-derive v0.9.4
##[error]The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.
##[group]Clock drift check
  local time: Wed Oct 25 00:01:59 UTC 2023
  network time: Wed, 25 Oct 2023 00:01:59 GMT
##[endgroup]
##[endgroup]
Session terminated, killing shell...[RUSTC-TIMING] tracing_attributes test:false 4.135
   Compiling thiserror-impl v1.0.47
[RUSTC-TIMING] tinyvec test:false 14.141
   Compiling thiserror-core-impl v1.0.38
[RUSTC-TIMING] rustc_macros test:false 4.802

[bors]

💔 Test failed - checks-actions

[dtolnay]

I see other inscrutable aarch64-gnu failure on other recent PRs, which succeed after retry. It does not look like a miscompile caused by this PR.

@bors retry

[bors]

⌛ Testing commit 45363f1 with merge 896afce...

[rust-log-analyzer]

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

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

failures:

---- [rustdoc] tests\rustdoc\issue-85454.rs stdout ----

error: rustdoc failed!
status: exit code: 0xc00000fd
command: PATH="C:\a\rust\rust\build\x86_64-pc-windows-gnu\stage2\bin;C:\a\rust\rust\build\x86_64-pc-windows-gnu\stage0-bootstrap-tools\x86_64-pc-windows-gnu\release\deps;C:\a\rust\rust\build\x86_64-pc-windows-gnu\stage0\bin;C:\a\rust\rust\ninja;C:\a\rust\rust\mingw64\bin;C:\hostedtoolcache\windows\Python\3.12.0\x64\Scripts;C:\hostedtoolcache\windows\Python\3.12.0\x64;C:\msys64\usr\bin;C:\a\rust\rust\sccache;C:\PROGRA~1\MongoDB\bin;C:\aliyun-cli;C:\vcpkg;C:\cf-cli;C:\Program Files (x86)\NSIS;C:\tools\zstd;C:\Program Files\Mercurial;C:\hostedtoolcache\windows\stack\2.13.1\x64;C:\cabal\bin;C:\ghcup\bin;C:\mingw64\bin;C:\Program Files\dotnet;C:\Program Files\MySQL\MySQL Server 5.7\bin;C:\Program Files\R\R-4.3.1\bin\x64;C:\SeleniumWebDrivers\GeckoDriver;C:\Program Files (x86)\sbt\bin;C:\Program Files (x86)\GitHub CLI;C:\Program Files\Git\bin;C:\Program Files (x86)\pipx_bin;C:\npm\prefix;C:\hostedtoolcache\windows\go\1.20.10\x64\bin;C:\hostedtoolcache\windows\Python\3.7.9\x64\Scripts;C:\hostedtoolcache\windows\Python\3.7.9\x64;C:\hostedtoolcache\windows\Ruby\2.5.9\x64\bin;C:\Program Files\OpenSSL\bin;C:\tools\kotlinc\bin;C:\hostedtoolcache\windows\Java_Temurin-Hotspot_jdk\8.0.382-5\x64\bin;C:\Program Files\ImageMagick-7.1.1-Q16-HDRI;C:\Program Files\Microsoft SDKs\Azure\CLI2\wbin;C:\ProgramData\kind;C:\Program Files\Eclipse Foundation\jdk-8.0.302.8-hotspot\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Windows\System32\OpenSSH;C:\ProgramData\Chocolatey\bin;C:\Program Files\PowerShell\7;C:\Program Files\Microsoft\Web Platform Installer;C:\Program Files\Microsoft SQL Server\130\Tools\Binn;C:\Program Files\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn;C:\Program Files (x86)\Windows Kits\10\Windows Performance Toolkit;C:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn;C:\Program Files (x86)\Microsoft SQL Server\120\DTS\Binn;C:\Program Files (x86)\Microsoft SQL Server\130\DTS\Binn;C:\Program Files (x86)\Microsoft SQL Server\140\DTS\Binn;C:\Program Files (x86)\Microsoft SQL Server\150\DTS\Binn;C:\Program Files (x86)\Microsoft SQL Server\160\DTS\Binn;C:\Strawberry\c\bin;C:\Strawberry\perl\site\bin;C:\Strawberry\perl\bin;C:\ProgramData\chocolatey\lib\pulumi\tools\Pulumi\bin;C:\Program Files\TortoiseSVN\bin;C:\Program Files\CMake\bin;C:\ProgramData\chocolatey\lib\maven\apache-maven-3.8.7\bin;C:\Program Files\Microsoft Service Fabric\bin\Fabric\Fabric.Code;C:\Program Files\Microsoft SDKs\Service Fabric\Tools\ServiceFabricLocalClusterManager;C:\Program Files\nodejs;C:\Program Files\Git\cmd;C:\Program Files\Git\mingw64\bin;C:\Program Files\Git\usr\bin;C:\Program Files\GitHub CLI;C:\tools\php;C:\Program Files (x86)\sbt\bin;C:\SeleniumWebDrivers\ChromeDriver;C:\SeleniumWebDrivers\EdgeDriver;C:\Program Files\Amazon\AWSCLIV2;C:\Program Files\Amazon\SessionManagerPlugin\bin;C:\Program Files\Amazon\AWSSAMCLI\bin;C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\bin;C:\Program Files (x86)\Microsoft BizTalk Server;C:\Program Files\LLVM\bin;C:\Users\runneradmin\.dotnet\tools;C:\Users\runneradmin\.cargo\bin;C:\Users\runneradmin\AppData\Local\Microsoft\WindowsApps" "C:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2\\bin\\rustdoc.exe" "-L" "C:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\stage2\\lib\\rustlib\\x86_64-pc-windows-gnu\\lib" "-L" "C:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\rustdoc\\issue-85454\\auxiliary" "-o" "C:\\a\\rust\\rust\\build\\x86_64-pc-windows-gnu\\test\\rustdoc\\issue-85454" "--deny" "warnings" "C:\\a\\rust\\rust\\tests\\rustdoc\\issue-85454.rs" "-A" "internal_features"
--- stderr -------------------------------

thread 'main' has overflowed its stack
------------------------------------------

[bors]

💔 Test failed - checks-actions

[dtolnay]

@bors retry

[bors]

⌛ Testing commit 45363f1 with merge c716f18...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing c716f18 to master...

[rust-timer]

Finished benchmarking commit (c716f18): 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)	-3.4%	[-4.7%, -2.2%]	2
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)	-5.2%	[-5.8%, -4.5%]	3
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: missing data
Artifact size: 304.45 MiB -> 304.44 MiB (-0.00%)