SOURCE_FILE
  IMPL
    IMPL_KW "impl"
    GENERIC_PARAM_LIST
      L_ANGLE "<"
      TYPE_PARAM
        NAME
          IDENT "T"
        COLON ":"
        WHITESPACE "\n"
        TYPE_BOUND_LIST
    ERROR
      USE_KW "use"
  WHITESPACE " "
  ERROR
    PATH
      PATH_SEGMENT
        NAME_REF
          IDENT "std"
  ERROR
    SEMICOLON ";"
  WHITESPACE "\n"
error 8: expected R_ANGLE
error 8: expected type
error 11: expected `{`
error 15: expected an item
error 15: expected an item
