[clang-tidy] False positive modernize-use-default-member-init warning in clang-tidy-21

[hebasto]

For the following code:

struct A
{
    A(int i) : f((i & 0x1f) == 1) {}
    bool f;
};

clang-tidy-21 produces a false positive warning:

$ clang-tidy-21 test.cpp -checks=modernize-* --
1 warning generated.
<redacted>/test.cpp:4:10: warning: use default member initializer for 'f' [modernize-use-default-member-init]
    3 |     A(int i) : f((i & 0x1f) == 1) {}
      |                ~~~~~~~~~~~~~~~~~~
    4 |     bool f;
      |          ^
      |           {(i & 0x1f) == 1}

cland-tidy-20 works just fine.

$ clang-tidy-21 --version
Ubuntu LLVM version 21.1.2
  Optimized build.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Hennadii Stepanov (hebasto)

For the following code: ```c++ struct A { A(int i) : f((i & 0x1f) == 1) {} bool f; }; ``` clang-tidy-21 produces a false positive warning: ```sh $ clang-tidy-21 test.cpp -checks=modernize-* -- 1 warning generated. <redacted>/test.cpp:4:10: warning: use default member initializer for 'f' [modernize-use-default-member-init] 3 | A(int i) : f((i & 0x1f) == 1) {} | ~~~~~~~~~~~~~~~~~~ 4 | bool f; | ^ | {(i & 0x1f) == 1} ```

cland-tidy-20 works just fine.

$ clang-tidy-21 --version
Ubuntu LLVM version 21.1.2
  Optimized build.

[vbvictor]

Should probably be fixed by #159392.