public void evaluateEqual(BinaryExpression expression, boolean defineVariable) {
    AsmClassGenerator acg = controller.getAcg();
    CompileStack compileStack = controller.getCompileStack();
    OperandStack operandStack = controller.getOperandStack();
    Expression rightExpression = expression.getRightExpression();
    Expression leftExpression = expression.getLeftExpression();
    ClassNode lhsType =
        controller.getTypeChooser().resolveType(leftExpression, controller.getClassNode());

    if (defineVariable
        && rightExpression instanceof EmptyExpression
        && !(leftExpression instanceof TupleExpression)) {
      VariableExpression ve = (VariableExpression) leftExpression;
      BytecodeVariable var =
          compileStack.defineVariable(
              ve, controller.getTypeChooser().resolveType(ve, controller.getClassNode()), false);
      operandStack.loadOrStoreVariable(var, false);
      return;
    }

    // let's evaluate the RHS and store the result
    ClassNode rhsType;
    if (rightExpression instanceof ListExpression && lhsType.isArray()) {
      ListExpression list = (ListExpression) rightExpression;
      ArrayExpression array =
          new ArrayExpression(lhsType.getComponentType(), list.getExpressions());
      array.setSourcePosition(list);
      array.visit(acg);
    } else if (rightExpression instanceof EmptyExpression) {
      rhsType = leftExpression.getType();
      loadInitValue(rhsType);
    } else {
      rightExpression.visit(acg);
    }
    rhsType = operandStack.getTopOperand();

    boolean directAssignment = defineVariable && !(leftExpression instanceof TupleExpression);
    int rhsValueId;
    if (directAssignment) {
      VariableExpression var = (VariableExpression) leftExpression;
      if (var.isClosureSharedVariable() && ClassHelper.isPrimitiveType(rhsType)) {
        // GROOVY-5570: if a closure shared variable is a primitive type, it must be boxed
        rhsType = ClassHelper.getWrapper(rhsType);
        operandStack.box();
      }

      // ensure we try to unbox null to cause a runtime NPE in case we assign
      // null to a primitive typed variable, even if it is used only in boxed
      // form as it is closure shared
      if (var.isClosureSharedVariable()
          && ClassHelper.isPrimitiveType(var.getOriginType())
          && isNull(rightExpression)) {
        operandStack.doGroovyCast(var.getOriginType());
        // these two are never reached in bytecode and only there
        // to avoid verifyerrors and compiler infrastructure hazzle
        operandStack.box();
        operandStack.doGroovyCast(lhsType);
      }
      // normal type transformation
      if (!ClassHelper.isPrimitiveType(lhsType) && isNull(rightExpression)) {
        operandStack.replace(lhsType);
      } else {
        operandStack.doGroovyCast(lhsType);
      }
      rhsType = lhsType;
      rhsValueId = compileStack.defineVariable(var, lhsType, true).getIndex();
    } else {
      rhsValueId = compileStack.defineTemporaryVariable("$rhs", rhsType, true);
    }
    // TODO: if rhs is VariableSlotLoader already, then skip crating a new one
    BytecodeExpression rhsValueLoader = new VariableSlotLoader(rhsType, rhsValueId, operandStack);

    // assignment for subscript
    if (leftExpression instanceof BinaryExpression) {
      BinaryExpression leftBinExpr = (BinaryExpression) leftExpression;
      if (leftBinExpr.getOperation().getType() == Types.LEFT_SQUARE_BRACKET) {
        assignToArray(
            expression,
            leftBinExpr.getLeftExpression(),
            leftBinExpr.getRightExpression(),
            rhsValueLoader);
      }
      compileStack.removeVar(rhsValueId);
      return;
    }

    compileStack.pushLHS(true);

    // multiple declaration
    if (leftExpression instanceof TupleExpression) {
      TupleExpression tuple = (TupleExpression) leftExpression;
      int i = 0;
      for (Expression e : tuple.getExpressions()) {
        VariableExpression var = (VariableExpression) e;
        MethodCallExpression call =
            new MethodCallExpression(
                rhsValueLoader, "getAt", new ArgumentListExpression(new ConstantExpression(i)));
        call.visit(acg);
        i++;
        if (defineVariable) {
          operandStack.doGroovyCast(var);
          compileStack.defineVariable(var, true);
          operandStack.remove(1);
        } else {
          acg.visitVariableExpression(var);
        }
      }
    }
    // single declaration
    else if (defineVariable) {
      rhsValueLoader.visit(acg);
      operandStack.remove(1);
      compileStack.popLHS();
      return;
    }
    // normal assignment
    else {
      int mark = operandStack.getStackLength();
      // to leave a copy of the rightExpression value on the stack after the assignment.
      rhsValueLoader.visit(acg);
      TypeChooser typeChooser = controller.getTypeChooser();
      ClassNode targetType = typeChooser.resolveType(leftExpression, controller.getClassNode());
      operandStack.doGroovyCast(targetType);
      leftExpression.visit(acg);
      operandStack.remove(operandStack.getStackLength() - mark);
    }
    compileStack.popLHS();

    // return value of assignment
    rhsValueLoader.visit(acg);
    compileStack.removeVar(rhsValueId);
  }