public static void warnAboutUnknownSourceType(Stella_Object tree) {
    if (Stella.warnAboutUndefinedMethodsP()) {
      { Surrogate testValue000 = Stella_Object.safePrimaryType(tree);

        if (Surrogate.subtypeOfSymbolP(testValue000)) {
          { Symbol tree000 = ((Symbol)(tree));

            return;
          }
        }
        else if (testValue000 == Stella.SGT_STELLA_CONS) {
          { Cons tree000 = ((Cons)(tree));

            { GeneralizedSymbol testValue001 = ((GeneralizedSymbol)(tree000.value));

              if ((testValue001 == Stella.SYM_STELLA_VERBATIM) ||
                  (testValue001 == Stella.SYM_STELLA_VRLET)) {
                return;
              }
              else if (testValue001 == Stella.SYM_STELLA_SYS_CALL_METHOD) {
                if (Symbol.symbolCommonLispP(((Symbol)(tree000.rest.rest.value))) ||
                    (Stella_Class.lookupSlot(((Stella_Class)(((Surrogate)(tree000.rest.value)).surrogateValue)), ((Symbol)(tree000.rest.rest.value))) == null)) {
                  return;
                }
              }
              else if (testValue001 == Stella.SYM_STELLA_SYS_CALL_FUNCTION) {
                if (Symbol.lookupFunction(((Symbol)(tree000.rest.value))).slotBaseType == Stella.SGT_STELLA_UNKNOWN) {
                  return;
                }
              }
              else if ((testValue001 == Stella.SYM_STELLA_TYPED_SYS) ||
                  (testValue001 == Stella.SYM_STELLA_SYS_INLINE_CALL)) {
                Stella_Object.warnAboutUnknownSourceType(tree000.rest.value);
                return;
              }
              else {
              }
            }
          }
        }
        else {
          if (tree == null) {
            return;
          }
        }
      }
      { 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(" The expression");
              Stella.STANDARD_ERROR.nativeStream.println("   `" + Stella_Object.deUglifyParseTree(tree) + "'");
              Stella.STANDARD_ERROR.nativeStream.println(" has UNKNOWN type.");
            }
;
          }

        } finally {
          Stella.$PRINTREADABLYp$.set(old$PrintreadablyP$000);
        }
      }
    }
  }