private void evaluateElvisOperatorExpression(ElvisOperatorExpression expression) {
    MethodVisitor mv = controller.getMethodVisitor();
    CompileStack compileStack = controller.getCompileStack();
    OperandStack operandStack = controller.getOperandStack();
    TypeChooser typeChooser = controller.getTypeChooser();

    Expression boolPart = expression.getBooleanExpression().getExpression();
    Expression falsePart = expression.getFalseExpression();

    ClassNode truePartType = typeChooser.resolveType(boolPart, controller.getClassNode());
    ClassNode falsePartType = typeChooser.resolveType(falsePart, controller.getClassNode());
    ClassNode common = WideningCategories.lowestUpperBound(truePartType, falsePartType);

    // x?:y is equal to x?x:y, which evals to
    //      var t=x; boolean(t)?t:y
    // first we load x, dup it, convert the dupped to boolean, then
    // jump depending on the value. For true we are done, for false we
    // have to load y, thus we first remove x and then load y.
    // But since x and y may have different stack lengths, this cannot work
    // Thus we have to have to do the following:
    // Be X the type of x, Y the type of y and S the common supertype of
    // X and Y, then we have to see x?:y as
    //      var t=x;boolean(t)?S(t):S(y)
    // so we load x, dup it, store the value in a local variable (t), then
    // do boolean conversion. In the true part load t and cast it to S,
    // in the false part load y and cast y to S

    // load x, dup it, store one in $t and cast the remaining one to boolean
    int mark = operandStack.getStackLength();
    boolPart.visit(controller.getAcg());
    operandStack.dup();
    if (ClassHelper.isPrimitiveType(truePartType)
        && !ClassHelper.isPrimitiveType(operandStack.getTopOperand())) {
      truePartType = ClassHelper.getWrapper(truePartType);
    }
    int retValueId = compileStack.defineTemporaryVariable("$t", truePartType, true);
    operandStack.castToBool(mark, true);

    Label l0 = operandStack.jump(IFEQ);
    // true part: load $t and cast to S
    operandStack.load(truePartType, retValueId);
    operandStack.doGroovyCast(common);
    Label l1 = new Label();
    mv.visitJumpInsn(GOTO, l1);

    // false part: load false expression and cast to S
    mv.visitLabel(l0);
    falsePart.visit(controller.getAcg());
    operandStack.doGroovyCast(common);

    // finish and cleanup
    mv.visitLabel(l1);
    compileStack.removeVar(retValueId);
    controller.getOperandStack().replace(common, 2);
  }
  private void doConvertAndCast(ClassNode targetType, boolean coerce) {
    int size = stack.size();
    throwExceptionForNoStackElement(size, targetType, coerce);

    ClassNode top = stack.get(size - 1);
    targetType = targetType.redirect();
    if (targetType == top) return;

    if (coerce) {
      controller.getInvocationWriter().coerce(top, targetType);
      return;
    }

    boolean primTarget = ClassHelper.isPrimitiveType(targetType);
    boolean primTop = ClassHelper.isPrimitiveType(top);

    if (primTop && primTarget) {
      // here we box and unbox to get the goal type
      if (convertPrimitive(top, targetType)) {
        replace(targetType);
        return;
      }
      box();
    } else if (primTop) {
      // top is primitive, target is not
      // so box and do groovy cast
      controller.getInvocationWriter().castToNonPrimitiveIfNecessary(top, targetType);
    } else if (primTarget) {
      // top is not primitive so unbox
      // leave that BH#doCast later
    } else {
      controller.getInvocationWriter().castToNonPrimitiveIfNecessary(top, targetType);
    }

    MethodVisitor mv = controller.getMethodVisitor();
    if (primTarget
        && !ClassHelper.boolean_TYPE.equals(targetType)
        && !primTop
        && ClassHelper.getWrapper(targetType).equals(top)) {
      BytecodeHelper.doCastToPrimitive(mv, top, targetType);
    } else {
      top = stack.get(size - 1);
      if (!WideningCategories.implementsInterfaceOrSubclassOf(top, targetType)) {
        BytecodeHelper.doCast(mv, targetType);
      }
    }
    replace(targetType);
  }
  private void evaluateNormalTernary(TernaryExpression expression) {
    MethodVisitor mv = controller.getMethodVisitor();
    OperandStack operandStack = controller.getOperandStack();
    TypeChooser typeChooser = controller.getTypeChooser();

    Expression boolPart = expression.getBooleanExpression();
    Expression truePart = expression.getTrueExpression();
    Expression falsePart = expression.getFalseExpression();

    ClassNode truePartType = typeChooser.resolveType(truePart, controller.getClassNode());
    ClassNode falsePartType = typeChooser.resolveType(falsePart, controller.getClassNode());
    ClassNode common = WideningCategories.lowestUpperBound(truePartType, falsePartType);

    // we compile b?x:y as
    //      boolean(b)?S(x):S(y), S = common super type of x,y
    // so we load b, do boolean conversion.
    // In the true part load x and cast it to S,
    // in the false part load y and cast y to S

    // load b and convert to boolean
    int mark = operandStack.getStackLength();
    boolPart.visit(controller.getAcg());
    operandStack.castToBool(mark, true);

    Label l0 = operandStack.jump(IFEQ);
    // true part: load x and cast to S
    truePart.visit(controller.getAcg());
    operandStack.doGroovyCast(common);
    Label l1 = new Label();
    mv.visitJumpInsn(GOTO, l1);

    // false part: load y and cast to S
    mv.visitLabel(l0);
    falsePart.visit(controller.getAcg());
    operandStack.doGroovyCast(common);

    // finish and cleanup
    mv.visitLabel(l1);
    controller.getOperandStack().replace(common, 2);
  }
  Expression transformBinaryExpression(final BinaryExpression bin) {
    if (bin instanceof DeclarationExpression) {
      Expression optimized = transformDeclarationExpression(bin);
      if (optimized != null) {
        return optimized;
      }
    }
    Object[] list = bin.getNodeMetaData(BINARY_EXP_TARGET);
    Token operation = bin.getOperation();
    int operationType = operation.getType();
    Expression rightExpression = bin.getRightExpression();
    Expression leftExpression = bin.getLeftExpression();
    if (bin instanceof DeclarationExpression && leftExpression instanceof VariableExpression) {
      ClassNode declarationType = ((VariableExpression) leftExpression).getOriginType();
      if (rightExpression instanceof ConstantExpression) {
        ClassNode unwrapper = ClassHelper.getUnwrapper(declarationType);
        ClassNode wrapper = ClassHelper.getWrapper(declarationType);
        if (!rightExpression.getType().equals(declarationType)
            && wrapper.isDerivedFrom(ClassHelper.Number_TYPE)
            && WideningCategories.isDoubleCategory(unwrapper)) {
          ConstantExpression constant = (ConstantExpression) rightExpression;
          if (constant.getValue() != null) {
            return optimizeConstantInitialization(
                bin, operation, constant, leftExpression, declarationType);
          }
        }
      }
    }
    if (operationType == Types.EQUAL && leftExpression instanceof PropertyExpression) {
      MethodNode directMCT =
          leftExpression.getNodeMetaData(StaticTypesMarker.DIRECT_METHOD_CALL_TARGET);
      if (directMCT != null) {
        return transformPropertyAssignmentToSetterCall(
            (PropertyExpression) leftExpression, rightExpression, directMCT);
      }
    }
    if (operationType == Types.COMPARE_EQUAL || operationType == Types.COMPARE_NOT_EQUAL) {
      // let's check if one of the operands is the null constant
      CompareToNullExpression compareToNullExpression = null;
      if (isNullConstant(leftExpression)) {
        compareToNullExpression =
            new CompareToNullExpression(
                staticCompilationTransformer.transform(rightExpression),
                operationType == Types.COMPARE_EQUAL);
      } else if (isNullConstant(rightExpression)) {
        compareToNullExpression =
            new CompareToNullExpression(
                staticCompilationTransformer.transform(leftExpression),
                operationType == Types.COMPARE_EQUAL);
      }
      if (compareToNullExpression != null) {
        compareToNullExpression.setSourcePosition(bin);
        return compareToNullExpression;
      }
    } else if (operationType == Types.KEYWORD_IN) {
      return convertInOperatorToTernary(bin, rightExpression, leftExpression);
    }
    if (list != null) {
      if (operationType == Types.COMPARE_TO) {
        StaticTypesTypeChooser typeChooser = staticCompilationTransformer.getTypeChooser();
        ClassNode classNode = staticCompilationTransformer.getClassNode();
        ClassNode leftType = typeChooser.resolveType(leftExpression, classNode);
        if (leftType.implementsInterface(ClassHelper.COMPARABLE_TYPE)) {
          ClassNode rightType = typeChooser.resolveType(rightExpression, classNode);
          if (rightType.implementsInterface(ClassHelper.COMPARABLE_TYPE)) {
            Expression left = staticCompilationTransformer.transform(leftExpression);
            Expression right = staticCompilationTransformer.transform(rightExpression);
            MethodCallExpression call =
                new MethodCallExpression(left, "compareTo", new ArgumentListExpression(right));
            call.setImplicitThis(false);
            call.setMethodTarget(COMPARE_TO_METHOD);

            CompareIdentityExpression compareIdentity = new CompareIdentityExpression(left, right);
            compareIdentity.putNodeMetaData(
                StaticTypesMarker.INFERRED_RETURN_TYPE, ClassHelper.boolean_TYPE);
            TernaryExpression result =
                new TernaryExpression(
                    new BooleanExpression(compareIdentity), // a==b
                    CONSTANT_ZERO,
                    new TernaryExpression(
                        new BooleanExpression(new CompareToNullExpression(left, true)), // a==null
                        CONSTANT_MINUS_ONE,
                        new TernaryExpression(
                            new BooleanExpression(
                                new CompareToNullExpression(right, true)), // b==null
                            CONSTANT_ONE,
                            call)));
            compareIdentity.putNodeMetaData(
                StaticTypesMarker.INFERRED_RETURN_TYPE, ClassHelper.int_TYPE);
            result.putNodeMetaData(StaticTypesMarker.INFERRED_TYPE, ClassHelper.int_TYPE);
            TernaryExpression expr = (TernaryExpression) result.getFalseExpression();
            expr.putNodeMetaData(StaticTypesMarker.INFERRED_TYPE, ClassHelper.int_TYPE);
            expr.getFalseExpression()
                .putNodeMetaData(StaticTypesMarker.INFERRED_TYPE, ClassHelper.int_TYPE);
            return result;
          }
        }
      }
      boolean isAssignment = StaticTypeCheckingSupport.isAssignment(operationType);
      MethodCallExpression call;
      MethodNode node = (MethodNode) list[0];
      String name = (String) list[1];
      Expression left = staticCompilationTransformer.transform(leftExpression);
      Expression right = staticCompilationTransformer.transform(rightExpression);
      BinaryExpression optimized = tryOptimizeCharComparison(left, right, bin);
      if (optimized != null) {
        optimized.removeNodeMetaData(BINARY_EXP_TARGET);
        return transformBinaryExpression(optimized);
      }
      call = new MethodCallExpression(left, name, new ArgumentListExpression(right));
      call.setImplicitThis(false);
      call.setMethodTarget(node);
      MethodNode adapter = StaticCompilationTransformer.BYTECODE_BINARY_ADAPTERS.get(operationType);
      if (adapter != null) {
        ClassExpression sba =
            new ClassExpression(StaticCompilationTransformer.BYTECODE_ADAPTER_CLASS);
        // replace with compareEquals
        call =
            new MethodCallExpression(sba, "compareEquals", new ArgumentListExpression(left, right));
        call.setMethodTarget(adapter);
        call.setImplicitThis(false);
      }
      if (!isAssignment) return call;
      // case of +=, -=, /=, ...
      // the method represents the operation type only, and we must add an assignment
      return new BinaryExpression(
          left, Token.newSymbol("=", operation.getStartLine(), operation.getStartColumn()), call);
    }
    if (bin.getOperation().getType() == Types.EQUAL
        && leftExpression instanceof TupleExpression
        && rightExpression instanceof ListExpression) {
      // multiple assignment
      ListOfExpressionsExpression cle = new ListOfExpressionsExpression();
      boolean isDeclaration = bin instanceof DeclarationExpression;
      List<Expression> leftExpressions = ((TupleExpression) leftExpression).getExpressions();
      List<Expression> rightExpressions = ((ListExpression) rightExpression).getExpressions();
      Iterator<Expression> leftIt = leftExpressions.iterator();
      Iterator<Expression> rightIt = rightExpressions.iterator();
      if (isDeclaration) {
        while (leftIt.hasNext()) {
          Expression left = leftIt.next();
          if (rightIt.hasNext()) {
            Expression right = rightIt.next();
            BinaryExpression bexp = new DeclarationExpression(left, bin.getOperation(), right);
            bexp.setSourcePosition(right);
            cle.addExpression(bexp);
          }
        }
      } else {
        // (next, result) = [ result, next+result ]
        // -->
        // def tmp1 = result
        // def tmp2 = next+result
        // next = tmp1
        // result = tmp2
        int size = rightExpressions.size();
        List<Expression> tmpAssignments = new ArrayList<Expression>(size);
        List<Expression> finalAssignments = new ArrayList<Expression>(size);
        for (int i = 0; i < Math.min(size, leftExpressions.size()); i++) {
          Expression left = leftIt.next();
          Expression right = rightIt.next();
          VariableExpression tmpVar = new VariableExpression("$tmpVar$" + tmpVarCounter++);
          BinaryExpression bexp = new DeclarationExpression(tmpVar, bin.getOperation(), right);
          bexp.setSourcePosition(right);
          tmpAssignments.add(bexp);
          bexp = new BinaryExpression(left, bin.getOperation(), new VariableExpression(tmpVar));
          bexp.setSourcePosition(left);
          finalAssignments.add(bexp);
        }
        for (Expression tmpAssignment : tmpAssignments) {
          cle.addExpression(tmpAssignment);
        }
        for (Expression finalAssignment : finalAssignments) {
          cle.addExpression(finalAssignment);
        }
      }
      return staticCompilationTransformer.transform(cle);
    }
    return staticCompilationTransformer.superTransform(bin);
  }