public void visitAssertStatement(GrAssertStatement assertStatement) {
    final InstructionImpl assertInstruction = startNode(assertStatement);

    final GrExpression assertion = assertStatement.getAssertion();
    if (assertion != null) {
      assertion.accept(this);

      InstructionImpl positiveHead = myHead;

      List<GotoInstruction> negations = collectAndRemoveAllPendingNegations(assertStatement);
      if (!negations.isEmpty()) {
        interruptFlow();
        reduceAllNegationsIntoInstruction(assertStatement, negations);
      }

      GrExpression errorMessage = assertStatement.getErrorMessage();
      if (errorMessage != null) {
        errorMessage.accept(this);
      }
      addNode(new ThrowingInstruction(assertStatement));

      final PsiType type =
          TypesUtil.createTypeByFQClassName(
              CommonClassNames.JAVA_LANG_ASSERTION_ERROR, assertStatement);
      ExceptionInfo info = findCatch(type);
      if (info != null) {
        info.myThrowers.add(myHead);
      } else {
        addPendingEdge(null, myHead);
      }

      myHead = positiveHead;
    }
    finishNode(assertInstruction);
  }
  @Override
  public void visitUnaryExpression(GrUnaryExpression expression) {
    final GrExpression operand = expression.getOperand();
    if (operand == null) return;

    if (expression.getOperationTokenType() != mLNOT) {
      operand.accept(this);
      visitCall(expression);
      return;
    }

    ConditionInstruction cond = new ConditionInstruction(expression);
    addNodeAndCheckPending(cond);
    registerCondition(cond);

    operand.accept(this);
    visitCall(expression);

    myConditions.removeFirstOccurrence(cond);

    List<GotoInstruction> negations = collectAndRemoveAllPendingNegations(expression);

    InstructionImpl head = myHead;
    addNodeAndCheckPending(new PositiveGotoInstruction(expression, cond));
    handlePossibleReturn(expression);
    addPendingEdge(expression, myHead);

    if (negations.isEmpty()) {
      myHead = head;
    } else {
      myHead = reduceAllNegationsIntoInstruction(expression, negations);
    }
  }
    @Override
    public void visitBinaryExpression(GrBinaryExpression expression) {
      final IElementType type = expression.getOperationTokenType();
      final GrExpression left = expression.getLeftOperand();
      final GrExpression right = expression.getRightOperand();

      if (type == mREGEX_FIND || type == mREGEX_MATCH) {
        final PsiClassType string =
            TypesUtil.createType(CommonClassNames.JAVA_LANG_STRING, expression);
        myResult = createSimpleSubTypeResult(string);
        return;
      }

      final GrExpression other = myExpression == left ? right : left;
      final PsiType otherType = other != null ? other.getType() : null;

      if (otherType == null) return;

      if (type == mPLUS && otherType.equalsToText(CommonClassNames.JAVA_LANG_STRING)) {
        final PsiClassType obj = TypesUtil.getJavaLangObject(expression);
        myResult = createSimpleSubTypeResult(obj);
        return;
      }

      myResult = createSimpleSubTypeResult(otherType);
    }
  @Override
  public void visitCaseSection(GrCaseSection caseSection) {
    for (GrCaseLabel label : caseSection.getCaseLabels()) {
      GrExpression value = label.getValue();
      if (value != null) {
        value.accept(this);
      }
    }

    final GrStatement[] statements = caseSection.getStatements();

    // infer 'may be return' position
    int i;
    for (i = statements.length - 1; i >= 0 && statements[i] instanceof GrBreakStatement; i--) {}

    for (int j = 0; j < statements.length; j++) {
      GrStatement statement = statements[j];
      statement.accept(this);
      if (j == i) handlePossibleReturn(statement);
    }

    if (myHead != null) {
      addPendingEdge(caseSection, myHead);
    }
  }
 public void visitIfStatement(GrIfStatement ifStatement) {
   if (myExpression.equals(ifStatement.getCondition())) {
     myResult =
         new TypeConstraint[] {
           new SubtypeConstraint(TypesUtil.getJavaLangObject(ifStatement), PsiType.BOOLEAN)
         };
   } else if (myExpression.equals(ifStatement.getThenBranch())
       || myExpression.equals(ifStatement.getElseBranch())) {
     checkExitPoint();
   }
 }
    @Override
    public void visitCaseLabel(GrCaseLabel caseLabel) {
      final PsiElement parent = caseLabel.getParent().getParent();
      assert parent instanceof GrSwitchStatement : parent + " of class " + parent.getClass();
      final GrExpression condition = ((GrSwitchStatement) parent).getCondition();
      if (condition == null) return;

      final PsiType type = condition.getType();
      if (type == null) return;

      myResult = new TypeConstraint[] {SubtypeConstraint.create(type)};
    }
 private void addForLoopBreakingEdge(GrForStatement forStatement, @Nullable GrForClause clause) {
   if (clause instanceof GrTraditionalForClause) {
     final GrExpression condition = ((GrTraditionalForClause) clause).getCondition();
     if (condition != null) {
       condition.accept(this);
       if (!alwaysTrue(condition)) {
         addPendingEdge(forStatement, myHead); // break cycle
       }
     }
   } else {
     addPendingEdge(forStatement, myHead); // break cycle
   }
 }
  public void visitReturnStatement(GrReturnStatement returnStatement) {
    boolean isNodeNeeded = myHead == null || myHead.getElement() != returnStatement;
    final GrExpression value = returnStatement.getReturnValue();
    if (value != null) value.accept(this);

    if (isNodeNeeded) {
      InstructionImpl returnInstruction = startNode(returnStatement);
      addPendingEdge(null, myHead);
      finishNode(returnInstruction);
    } else {
      addPendingEdge(null, myHead);
    }
    interruptFlow();
  }
 @Override
 public void visitOpenBlock(GrOpenBlock block) {
   final GrStatement[] statements = block.getStatements();
   if (statements.length > 0 && myExpression.equals(statements[statements.length - 1])) {
     checkExitPoint();
   }
 }
    @Override
    public void visitSwitchStatement(GrSwitchStatement switchStatement) {
      final GrCaseSection[] sections = switchStatement.getCaseSections();
      List<PsiType> types = new ArrayList<PsiType>(sections.length);
      for (GrCaseSection section : sections) {
        final GrExpression value = section.getCaseLabel().getValue();
        final PsiType type = value != null ? value.getType() : null;
        if (type != null) types.add(type);
      }

      final PsiType upperBoundNullable =
          TypesUtil.getLeastUpperBoundNullable(types, switchStatement.getManager());
      if (upperBoundNullable == null) return;

      myResult = new TypeConstraint[] {SubtypeConstraint.create(upperBoundNullable)};
    }
 public void visitWhileStatement(GrWhileStatement whileStatement) {
   if (myExpression.equals(whileStatement.getCondition())) {
     myResult =
         new TypeConstraint[] {
           new SubtypeConstraint(TypesUtil.getJavaLangObject(whileStatement), PsiType.BOOLEAN)
         };
   }
 }
 public void visitTraditionalForClause(GrTraditionalForClause forClause) {
   if (myExpression.equals(forClause.getCondition())) {
     myResult =
         new TypeConstraint[] {
           new SubtypeConstraint(TypesUtil.getJavaLangObject(forClause), PsiType.BOOLEAN)
         };
   }
 }
  public void visitAssignmentExpression(GrAssignmentExpression expression) {
    GrExpression lValue = expression.getLValue();
    if (expression.getOperationTokenType() != mASSIGN) {
      if (lValue instanceof GrReferenceExpression
          && myPolicy.isReferenceAccepted((GrReferenceExpression) lValue)) {
        String referenceName = ((GrReferenceExpression) lValue).getReferenceName();
        if (referenceName != null) {
          addNodeAndCheckPending(new ReadWriteVariableInstruction(referenceName, lValue, READ));
        }
      }
    }

    GrExpression rValue = expression.getRValue();
    if (rValue != null) {
      rValue.accept(this);
      lValue.accept(this);
    }
  }
 @Nullable
 private static PsiType getNominalTypeNoRecursion(@NotNull final GrExpression expression) {
   if (expression instanceof GrNewExpression) {
     return expression.getType();
   } else if (expression instanceof GrReferenceExpression
       && ((GrReferenceExpression) expression).getQualifier() == null) {
     return getTypeByRef((GrReferenceExpression) expression);
   }
   return null;
 }
  @Override
  public void visitElvisExpression(GrElvisExpression expression) {
    GrExpression condition = expression.getCondition();
    GrExpression elseBranch = expression.getElseBranch();

    condition.accept(this);
    List<GotoInstruction> negations = collectAndRemoveAllPendingNegations(expression);

    InstructionImpl head = myHead;
    handlePossibleReturn(condition);
    addPendingEdge(expression, myHead);
    myHead = head;

    if (elseBranch != null) {
      head = reduceAllNegationsIntoInstruction(expression, negations);
      if (head != null) myHead = head;
      elseBranch.accept(this);
      handlePossibleReturn(elseBranch);
    }
  }
  public void visitThrowStatement(GrThrowStatement throwStatement) {
    final GrExpression exception = throwStatement.getException();
    if (exception == null) return;

    exception.accept(this);
    final InstructionImpl throwInstruction = new ThrowingInstruction(throwStatement);
    addNodeAndCheckPending(throwInstruction);

    interruptFlow();
    final PsiType type = getNominalTypeNoRecursion(exception);
    if (type != null) {
      ExceptionInfo info = findCatch(type);
      if (info != null) {
        info.myThrowers.add(throwInstruction);
      } else {
        addPendingEdge(null, throwInstruction);
      }
    } else {
      addPendingEdge(null, throwInstruction);
    }
  }
 public void visitAssignmentExpression(GrAssignmentExpression expression) {
   GrExpression rValue = expression.getRValue();
   GrExpression lValue = expression.getLValue();
   if (myExpression.equals(rValue)) {
     PsiType lType = lValue.getNominalType();
     if (lType != null) {
       myResult = new TypeConstraint[] {SubtypeConstraint.create(lType)};
     } else if (lValue instanceof GrReferenceExpression) {
       GroovyResolveResult result = ((GrReferenceExpression) lValue).advancedResolve();
       PsiElement resolved = result.getElement();
       if (resolved instanceof GrVariable) {
         PsiType type = ((GrVariable) resolved).getTypeGroovy();
         if (type != null) {
           myResult =
               new TypeConstraint[] {
                 SubtypeConstraint.create(result.getSubstitutor().substitute(type))
               };
         }
       }
     }
   } else if (myExpression.equals(lValue)) {
     if (rValue != null) {
       PsiType rType = rValue.getType();
       if (rType != null) {
         myResult = new TypeConstraint[] {SupertypeConstraint.create(rType)};
       }
     }
   }
 }
    @Override
    public void visitAnnotationNameValuePair(GrAnnotationNameValuePair nameValuePair) {
      if (myExpression.equals(nameValuePair.getValue())) {
        final PsiClass annot = ResolveUtil.resolveAnnotation(nameValuePair.getParent());
        if (annot != null) {
          final String name = nameValuePair.getName();
          if (name != null) {
            final PsiMethod[] attrs = annot.findMethodsByName(name, false);
            if (attrs.length > 0) {
              PsiType type = attrs[0].getReturnType();
              while (type instanceof PsiArrayType) type = ((PsiArrayType) type).getComponentType();
              if (type != null && isAcceptableAnnotationValueType(type)) {
                myResult = createSimpleSubTypeResult(type);
              }
            }
          } else {
            final PsiMethod[] valueAttr = annot.findMethodsByName("value", false);
            boolean canHaveSimpleExpr = valueAttr.length > 0;
            final PsiMethod[] methods = annot.getMethods();
            for (PsiMethod method : methods) {
              if (!("value".equals(method.getName())
                  || method instanceof PsiAnnotationMethod
                      && ((PsiAnnotationMethod) method).getDefaultValue() != null)) {
                canHaveSimpleExpr = false;
              }
            }

            if (canHaveSimpleExpr) {
              PsiType type = valueAttr[0].getReturnType();
              while (type instanceof PsiArrayType) type = ((PsiArrayType) type).getComponentType();
              if (type != null && isAcceptableAnnotationValueType(type)) {
                myResult = createSimpleSubTypeResult(type);
              }
            }
          }
        }
      }
    }
    public void visitMethodCallExpression(GrMethodCallExpression methodCall) {
      final GrExpression invokedExpression = methodCall.getInvokedExpression();
      if (myExpression.equals(invokedExpression)) {
        myResult =
            new TypeConstraint[] {
              SubtypeConstraint.create(GroovyCommonClassNames.GROOVY_LANG_CLOSURE, methodCall)
            };
        return;
      }

      final GrClosableBlock[] closureArgs = methodCall.getClosureArguments();
      //noinspection SuspiciousMethodCalls
      final int closureIndex = Arrays.asList(closureArgs).indexOf(myExpression);
      if (closureIndex >= 0) {
        List<TypeConstraint> constraints = new ArrayList<TypeConstraint>();
        for (GroovyResolveResult variant : ResolveUtil.getCallVariants(myExpression)) {
          final GrArgumentList argumentList = methodCall.getArgumentList();
          final GrNamedArgument[] namedArgs =
              argumentList == null ? GrNamedArgument.EMPTY_ARRAY : argumentList.getNamedArguments();
          final GrExpression[] expressionArgs =
              argumentList == null
                  ? GrExpression.EMPTY_ARRAY
                  : argumentList.getExpressionArguments();
          try {
            final Map<GrExpression, Pair<PsiParameter, PsiType>> map =
                GrClosureSignatureUtil.mapArgumentsToParameters(
                    variant, methodCall, true, true, namedArgs, expressionArgs, closureArgs);
            addConstraintsFromMap(constraints, map);
          } catch (RuntimeException e) {
            LOG.error(
                "call: " + methodCall.getText() + "\nsymbol: " + variant.getElement().getText(), e);
          }
        }
        if (!constraints.isEmpty()) {
          myResult = constraints.toArray(new TypeConstraint[constraints.size()]);
        }
      }
    }
  @Override
  public void visitBinaryExpression(GrBinaryExpression expression) {
    final GrExpression left = expression.getLeftOperand();
    final GrExpression right = expression.getRightOperand();
    final IElementType opType = expression.getOperationTokenType();

    if (ControlFlowBuilderUtil.isInstanceOfBinary(expression)) {
      expression.getLeftOperand().accept(this);
      processInstanceOf(expression);
      return;
    }

    if (opType != mLOR && opType != mLAND && opType != kIN) {
      left.accept(this);
      if (right != null) {
        right.accept(this);
      }
      visitCall(expression);
      return;
    }

    ConditionInstruction condition = new ConditionInstruction(expression);
    addNodeAndCheckPending(condition);
    registerCondition(condition);

    left.accept(this);

    if (right == null) return;

    final List<GotoInstruction> negations = collectAndRemoveAllPendingNegations(expression);

    visitCall(expression);

    if (opType == mLAND) {
      InstructionImpl head = myHead;
      if (negations.isEmpty()) {
        addNode(new NegatingGotoInstruction(expression, condition));
        handlePossibleReturn(expression);
        addPendingEdge(expression, myHead);
      } else {
        for (GotoInstruction negation : negations) {
          myHead = negation;
          handlePossibleReturn(expression);
          addPendingEdge(expression, myHead);
        }
      }
      myHead = head;
    } else /*if (opType == mLOR)*/ {
      final InstructionImpl instruction =
          addNodeAndCheckPending(
              new InstructionImpl(expression)); // collect all pending edges from left argument
      handlePossibleReturn(expression);
      addPendingEdge(expression, myHead);
      myHead = instruction;

      InstructionImpl head = reduceAllNegationsIntoInstruction(expression, negations);
      if (head != null) myHead = head;
      // addNode(new NegatingGotoInstruction(expression, myInstructionNumber++, condition));
    }
    myConditions.removeFirstOccurrence(condition);

    right.accept(this);
  }
 @Override
 public void visitParenthesizedExpression(GrParenthesizedExpression expression) {
   final GrExpression operand = expression.getOperand();
   if (operand != null) operand.accept(this);
 }
 @SuppressWarnings({"ConstantConditions"})
 public static boolean expressionsAreEquivalent(
     @Nullable GrExpression exp1, @Nullable GrExpression exp2) {
   if (exp1 == null && exp2 == null) {
     return true;
   }
   if (exp1 == null || exp2 == null) {
     return false;
   }
   GrExpression expToCompare1 = (GrExpression) PsiUtil.skipParentheses(exp1, false);
   GrExpression expToCompare2 = (GrExpression) PsiUtil.skipParentheses(exp2, false);
   final int type1 = getExpressionType(expToCompare1);
   final int type2 = getExpressionType(expToCompare2);
   if (type1 != type2) {
     return false;
   }
   switch (type1) {
     case THIS_EXPRESSION:
     case SUPER_EXPRESSION:
       return true;
     case LITERAL_EXPRESSION:
     case REFERENCE_EXPRESSION:
       final String text1 = expToCompare1.getText();
       final String text2 = expToCompare2.getText();
       return text1.equals(text2);
     case CALL_EXPRESSION:
       return methodCallExpressionsAreEquivalent(
           (GrMethodCall) expToCompare1, (GrMethodCall) expToCompare2);
     case NEW_EXPRESSION:
       return newExpressionsAreEquivalent(
           (GrNewExpression) expToCompare1, (GrNewExpression) expToCompare2);
     case ARRAY_LITERAL_EXPRESSION:
       return arrayDeclarationsAreEquivalent(
           (GrArrayDeclaration) expToCompare1, (GrArrayDeclaration) expToCompare2);
     case PREFIX_EXPRESSION:
       return prefixExpressionsAreEquivalent(
           (GrUnaryExpression) expToCompare1, (GrUnaryExpression) expToCompare2);
     case POSTFIX_EXPRESSION:
       return postfixExpressionsAreEquivalent(
           (GrUnaryExpression) expToCompare1, (GrUnaryExpression) expToCompare2);
     case BINARY_EXPRESSION:
       return binaryExpressionsAreEquivalent(
           (GrBinaryExpression) expToCompare1, (GrBinaryExpression) expToCompare2);
     case ASSIGNMENT_EXPRESSION:
       return assignmentExpressionsAreEquivalent(
           (GrAssignmentExpression) expToCompare1, (GrAssignmentExpression) expToCompare2);
     case CONDITIONAL_EXPRESSION:
       return conditionalExpressionsAreEquivalent(
           (GrConditionalExpression) expToCompare1, (GrConditionalExpression) expToCompare2);
     case ELVIS_EXPRESSION:
       return elvisExpressionsAreEquivalent(
           (GrElvisExpression) expToCompare1, (GrElvisExpression) expToCompare2);
     case RANGE_EXPRESSION:
       return rangeExpressionsAreEquivalent(
           (GrRangeExpression) expToCompare1, (GrRangeExpression) expToCompare2);
     case TYPE_CAST_EXPRESSION:
       return typecastExpressionsAreEquivalent(
           (GrTypeCastExpression) expToCompare1, (GrTypeCastExpression) expToCompare2);
     case SAFE_CAST_EXPRESSION:
       return safecastExpressionsAreEquivalent(
           (GrSafeCastExpression) expToCompare1, (GrSafeCastExpression) expToCompare2);
     case INSTANCEOF_EXPRESSION:
       return instanceofExpressionsAreEquivalent(
           (GrInstanceOfExpression) expToCompare1, (GrInstanceOfExpression) expToCompare2);
     case INDEX_EXPRESSION:
       return indexExpressionsAreEquivalent(
           (GrIndexProperty) expToCompare1, (GrIndexProperty) expToCompare2);
     case LIST_OR_MAP_EXPRESSION:
       return listOrMapExpressionsAreEquivalent(
           (GrListOrMap) expToCompare1, (GrListOrMap) expToCompare2);
     case CLOSABLE_BLOCK_EXPRESSION:
       return closableBlockExpressionsAreEquivalent(
           (GrClosableBlock) expToCompare1, (GrClosableBlock) expToCompare2);
     case PROPERTY_SELECTION_EXPRESSION:
       return textOfExpressionsIsEquivalent(expToCompare1, expToCompare2); // todo
     default:
       return false;
   }
 }
 @Override
 public void visitThrowStatement(GrThrowStatement throwStatement) {
   final PsiClassType throwable =
       PsiType.getJavaLangThrowable(myExpression.getManager(), throwStatement.getResolveScope());
   myResult = new TypeConstraint[] {SubtypeConstraint.create(throwable)};
 }
 private static boolean textOfExpressionsIsEquivalent(
     GrExpression expToCompare1, GrExpression expToCompare2) {
   final String text1 = expToCompare1.getText();
   final String text2 = expToCompare2.getText();
   return text1.equals(text2);
 }
 public void visitVariable(GrVariable variable) {
   if (myExpression.equals(variable.getInitializerGroovy())) {
     PsiType type = variable.getType();
     myResult = createSimpleSubTypeResult(type);
   }
 }