[PATCH] D80514: [clang-tidy] modernize-use-trailing-return-type support for C++20 concepts and decltype

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


================
Comment at: clang-tools-extra/clang-tidy/modernize/UseTrailingReturnTypeCheck.cpp:430
+      AT->getKeyword() == AutoTypeKeyword::Auto &&
+      !hasAnyNestedLocalQualifiers(F->getDeclaredReturnType()))
+    return;
----------------
aaron.ballman wrote:
> bernhardmgruber wrote:
> > aaron.ballman wrote:
> > > Why do we need to check that there aren't any nested local qualifiers?
> > Because I would like the check to rewrite e.g. `const auto f();` into `auto f() -> const auto;`. If I omit the check for nested local qualifiers, then those kind of declarations would be skipped.
> I'm still wondering about this.
> Because I would like the check to rewrite e.g. const auto f(); into auto f() -> const auto;. If I omit the check for nested local qualifiers, then those kind of declarations would be skipped.

I don't think I understand why that's desirable though? What is it about the qualifier that makes it worthwhile to repeat the type like that?


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Comment at: clang-tools-extra/test/clang-tidy/checkers/modernize-use-trailing-return-type.cpp:1
-// RUN: %check_clang_tidy -std=c++14,c++17 %s modernize-use-trailing-return-type %t -- -- -fdeclspec -fexceptions
+// RUN: %check_clang_tidy -std=c++14-or-later %s modernize-use-trailing-return-type %t -- -- -fdeclspec -fexceptions -DCOMMAND_LINE_INT=int
 // FIXME: Fix the checker to work in C++20 mode, it is performing a
----------------
bernhardmgruber wrote:
> aaron.ballman wrote:
> > The change to the language standard line makes me wonder if the fixme below it is now stale, or if the test will fail in C++20 mode.
> I just ran the tests again using `python .\check_clang_tidy.py -std=c++20 .\checkers\modernize-use-trailing-return-type.cpp modernize-use-trailing-return-type aa -- -- -DCOMMAND_LINE_INT=int` and I did not see mentioning of the use of an uninitialized variable. But I run on Windows, maybe the issue just surfaces on another OS? Is there a way to trigger the CI again?
> 
> I removed the FIXME in question in the hope the issue resolved itself.
> But I run on Windows, maybe the issue just surfaces on another OS? Is there a way to trigger the CI again?

I also run on Windows so I can't easily test the behavior elsewhere for you. The CI will get triggered on new patch uploads, but I still don't always trust it. The bots are usually a more reliable source of CI truth but we have no way to speculatively trigger all the bots.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80514/new/

https://reviews.llvm.org/D80514