/in/foo.c:1:2: error: invalid preprocessing directive #ddaa
    1 | #ddaa
      |  ^~~~
/in/foo.c:2:1: error: unknown type name 'f'
    2 | f
      | ^
/in/foo.c:3:1: error: expected '=', ',', ';', 'asm' or '__attribute__' at end of input
    3 | a
      | ^