foo.c:1:1: error: expected identifier or '(' before numeric constant
    1 | 3
      | ^
foo.c:3:5: error: stray '#' in program
    3 | . . #
      |     ^
foo.c:4:3: error: invalid preprocessing directive #.
    4 | # . .
      |   ^
foo.c:8:3: error: stray '#' in program
    8 | . # .
      |   ^
foo.c:10:3: error: invalid preprocessing directive #.
   10 | # . .
      |   ^
foo.c:13:3: error: stray '#' in program
   13 | . # .
      |   ^
foo.c:15:3: error: invalid preprocessing directive #.
   15 | # . .
      |   ^