public static Cons extractOneInClause(Cons tail, Object [] MV_returnarray) {
    { Stella_Object variable = tail.value;
      Stella_Object operator = tail.rest.value;
      Cons clause = tail;

      if (!((Stella_Object.symbolP(variable) ||
          Stella_Object.consP(variable)) &&
          (Stella.getQuotedTree("((IN ON ISA) \"/STELLA\")", "/STELLA").memberP(operator) &&
           (tail.rest.rest.value != null)))) {
        { Object old$PrintreadablyP$000 = Stella.$PRINTREADABLYp$.get();

          try {
            Native.setBooleanSpecial(Stella.$PRINTREADABLYp$, true);
            Stella.signalTranslationError();
            if (!(Stella.suppressWarningsP())) {
              Stella.printErrorContext(">> ERROR: ", Stella.STANDARD_ERROR);
              {
                Stella.STANDARD_ERROR.nativeStream.println();
                Stella.STANDARD_ERROR.nativeStream.println(" Illegal syntax where 'IN', 'ON', or 'ISA' clause expected:");
                Stella.STANDARD_ERROR.nativeStream.println("   `" + Stella_Object.deUglifyParseTree(tail) + "'.");
              }
;
            }

          } finally {
            Stella.$PRINTREADABLYp$.set(old$PrintreadablyP$000);
          }
        }
        { Cons _return_temp = null;

          MV_returnarray[0] = Stella.NIL;
          return (_return_temp);
        }
      }
      clause.firstSetter(operator);
      clause.secondSetter(variable);
      tail = tail.rest.rest.rest;
      clause.rest.rest.rest = Stella.NIL;
      { Cons _return_temp = clause;

        MV_returnarray[0] = tail;
        return (_return_temp);
      }
    }
  }