This is a basic example of C-style cast detection using clang's AST Matchers in less than 60 lines of C++ code.

git clone [email protected]:thegameg/cast-matcher.git llvm/tools/clang/extra/cast-matcher

echo 'add_subdirectory(cast-matcher)' >> llvm/tools/clang/extra/CMakeLists.txt

Build using ninja cast-matcher or make cast-matcher.

is_cast.c:

#include <stddef.h>

void foo(void)
{
  int *i = NULL;
  void *a = (void *)i;
}

$ cast-matcher is_cast.c

is_cast.c:6:13: error: explicit cast detected
  void *a = (void *)i;
            ^~~~~~~~~
1 error generated.
Error while processing is_cast.c.