Clang AST how to match unary operator calls, excluding ones in decltype?

Question

I can easily match unary operator calls with the following query:

m unaryOperator(unless(isExpansionInSystemHeader()))

However, I want to exclude matches like the following:

decltype(&Func)

Is there a query that I can use to exclude those calls, or I should somehow exclude them from code?

Answer 1

Yes, use Traversal Matchers. For example,

// test.cpp
int foo();

int main() {
  int i=0;
  i++;

  int *k = &i;

  decltype(&foo) j;
  return 0;
}

with clang-query test.cpp --.

To match all unary operators:

clang-query> m unaryOperator()

Match #1:

/.../test.cpp:6:3: note: "root" binds here
  i++;
  ^~~

Match #2:

/.../test.cpp:8:12: note: "root" binds here
  int *k = &i;
           ^~

Match #3:

/.../test.cpp:10:12: note: "root" binds here
  decltype(&foo) j;
           ^~~~
3 matches.

To exclude &:

clang-query> m unaryOperator(unless(hasOperatorName("&")))

Match #1:

/.../test.cpp:6:3: note: "root" binds here
  i++;
  ^~~
1 match.

To exclude decltype:

clang-query> m unaryOperator(unless(hasAncestor(varDecl(hasType(decltypeType())))))

Match #1:

/.../test.cpp:6:3: note: "root" binds here
  i++;
  ^~~

Match #2:

/.../test.cpp:8:12: note: "root" binds here
  int *k = &i;
           ^~
2 matches.