If clang-tidy is installed and the project's source root contains a .clang-tidy (or _clang-tidy) file, Meson will automatically define a clang-tidy-fix target that runs run-clang-tidy tool with -fix option to apply the changes found by clang-tidy to the source code.
If you have defined your own clang-tidy-fix target, Meson will not generate its own target.