[clang-tools-extra] [clang-tidy] Add detection of decltype(nullptr) => std::nullptr_t to … (PR #224591)

[via cfe-commits]

github-actions[bot] wrote:

<!--LLVM CODE LINT COMMENT: clang-tidy-->


:warning: C/C++ code linter, clang-tidy found issues in your code. :warning:

<details>
<summary>
You can test this locally with the following command:
</summary>

```bash

git diff -U0 origin/main...HEAD -- clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.cpp clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h |
python3 clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py   -path build -p1 -quiet
```

</details>

<details>
<summary>
View the output from clang-tidy here.
</summary>

```
clang-tools-extra/clang-tidy/modernize/UseNullptrCheck.h:33:14: warning: invalid case style for member 'useNullptrt' [readability-identifier-naming]
   33 |   const bool useNullptrt;
      |              ^~~~~~~~~~~
      |              UseNullptrt
```

</details>


https://github.com/llvm/llvm-project/pull/224591