SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "foo"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    RET_TYPE
      PATH_TYPE
        PATH
          PATH_SEGMENT
            NAME_REF
              IDENT "usize"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n"
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "bar"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    RET_TYPE
      PATH_TYPE
        PATH
          PATH
            PATH_SEGMENT
              NAME_REF
                SUPER_KW "super"
          COLON2 "::"
          PATH_SEGMENT
            NAME_REF
              IDENT "Foo"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n"
error 9: missing thin-arrow `->`
error 27: missing thin-arrow `->`
