[clang-tidy] readability-implicit-bool-conversion emits useless fixit for comparisons in C

[5chmidti]

In C, the result of a comparison is defined as returning a 1 or a 0 of type int (C N3220 6.5.9.7 & 6.5.10.4).

https://godbolt.org/z/fTErfvzqW

bool foo() { return 1 != 0; }

[<source>:1:21: warning: implicit conversion 'int' -> 'bool' [readability-implicit-bool-conversion]](javascript:;)
    1 | bool foo() { return 1 != 0; }
      |                     ^     
      |                     (     ) != 0
1 warning generated.

The check should probably be adapted to check if the source expression of the cast is a comparison (ignoring parens), and just add a cast instead.

Additionally, a new option could be added to ignore the conversion warning in this case for C.

[llvmbot]

@llvm/issue-subscribers-bug

Author: Julian Schmidt (5chmidti)

In C, the result of a comparison is defined as returning a `1` or a `0` of type `int` (C N3220 6.5.9.7 & 6.5.10.4).

https://godbolt.org/z/fTErfvzqW

bool foo() { return 1 != 0; }

[<source>:1:21: warning: implicit conversion 'int' -> 'bool' [readability-implicit-bool-conversion]](javascript:;)
    1 | bool foo() { return 1 != 0; }
      |                     ^     
      |                     (     ) != 0
1 warning generated.

The check should probably be adapted to check if the source expression of the cast is a comparison (ignoring parens), and just add a cast instead.

Additionally, a new option could be added to ignore the conversion warning in this case for C.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Julian Schmidt (5chmidti)

In C, the result of a comparison is defined as returning a `1` or a `0` of type `int` (C N3220 6.5.9.7 & 6.5.10.4).

https://godbolt.org/z/fTErfvzqW

bool foo() { return 1 != 0; }

[<source>:1:21: warning: implicit conversion 'int' -> 'bool' [readability-implicit-bool-conversion]](javascript:;)
    1 | bool foo() { return 1 != 0; }
      |                     ^     
      |                     (     ) != 0
1 warning generated.

The check should probably be adapted to check if the source expression of the cast is a comparison (ignoring parens), and just add a cast instead.

Additionally, a new option could be added to ignore the conversion warning in this case for C.