SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "main"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE " "
        EXPR_STMT
          CLOSURE_EXPR
            FOR_BINDER
              FOR_KW "for"
              GENERIC_PARAM_LIST
                L_ANGLE "<"
                LIFETIME_PARAM
                  LIFETIME
                    LIFETIME_IDENT "'a"
                R_ANGLE ">"
            WHITESPACE " "
            PARAM_LIST
              PIPE "|"
              PIPE "|"
            WHITESPACE " "
            TUPLE_EXPR
              L_PAREN "("
              R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE " "
        R_CURLY "}"
  WHITESPACE "\n"
