SOURCE_FILE@0..24
  CONST@0..23
    CONST_KW@0..5 "const"
    WHITESPACE@5..6 " "
    MUT_KW@6..9 "mut"
    WHITESPACE@9..10 " "
    NAME@10..13
      IDENT@10..13 "FOO"
    COLON@13..14 ":"
    WHITESPACE@14..15 " "
    TUPLE_TYPE@15..17
      L_PAREN@15..16 "("
      R_PAREN@16..17 ")"
    WHITESPACE@17..18 " "
    EQ@18..19 "="
    WHITESPACE@19..20 " "
    TUPLE_EXPR@20..22
      L_PAREN@20..21 "("
      R_PAREN@21..22 ")"
    SEMICOLON@22..23 ";"
  WHITESPACE@23..24 "\n"
error 6..9: const globals cannot be mutable