private static String createInitializerReplacementText(
     PsiType varType, PsiExpression initializer) {
   final PsiType initializerType = initializer.getType();
   final PsiClassType rawType =
       initializerType instanceof PsiClassType
           ? ((PsiClassType) initializerType).rawType()
           : null;
   final PsiClassType rawVarType =
       varType instanceof PsiClassType ? ((PsiClassType) varType).rawType() : null;
   if (rawType != null
       && rawVarType != null
       && rawType.equalsToText(CommonClassNames.JAVA_UTIL_ARRAY_LIST)
       && rawVarType.equalsToText(CommonClassNames.JAVA_UTIL_LIST)) {
     return "toList()";
   } else if (rawType != null
       && rawVarType != null
       && rawType.equalsToText(CommonClassNames.JAVA_UTIL_HASH_SET)
       && rawVarType.equalsToText(CommonClassNames.JAVA_UTIL_SET)) {
     return "toSet()";
   } else if (rawType != null) {
     return "toCollection(" + rawType.getClassName() + "::new)";
   } else {
     return "toCollection(() -> " + initializer.getText() + ")";
   }
 }
  private static boolean isCollectCall(PsiStatement body, final PsiParameter parameter) {
    PsiIfStatement ifStatement = extractIfStatement(body);
    final PsiMethodCallExpression methodCallExpression = extractAddCall(body, ifStatement);
    if (methodCallExpression != null) {
      final PsiReferenceExpression methodExpression = methodCallExpression.getMethodExpression();
      final PsiExpression qualifierExpression = methodExpression.getQualifierExpression();
      PsiClass qualifierClass = null;
      if (qualifierExpression instanceof PsiReferenceExpression) {
        if (ReferencesSearch.search(parameter, new LocalSearchScope(qualifierExpression))
                .findFirst()
            != null) {
          return false;
        }
        final PsiElement resolve = ((PsiReferenceExpression) qualifierExpression).resolve();
        if (resolve instanceof PsiVariable) {
          if (ReferencesSearch.search(
                      resolve, new LocalSearchScope(methodCallExpression.getArgumentList()))
                  .findFirst()
              != null) {
            return false;
          }
        }
        qualifierClass = PsiUtil.resolveClassInType(qualifierExpression.getType());
      } else if (qualifierExpression == null) {
        final PsiClass enclosingClass = PsiTreeUtil.getParentOfType(body, PsiClass.class);
        if (PsiUtil.getEnclosingStaticElement(body, enclosingClass) == null) {
          qualifierClass = enclosingClass;
        }
      }

      if (qualifierClass != null
          && InheritanceUtil.isInheritor(
              qualifierClass, false, CommonClassNames.JAVA_UTIL_COLLECTION)) {

        while (ifStatement != null && PsiTreeUtil.isAncestor(body, ifStatement, false)) {
          final PsiExpression condition = ifStatement.getCondition();
          if (condition != null
              && isConditionDependsOnUpdatedCollections(condition, qualifierExpression))
            return false;
          ifStatement = PsiTreeUtil.getParentOfType(ifStatement, PsiIfStatement.class);
        }

        final PsiElement resolve = methodExpression.resolve();
        if (resolve instanceof PsiMethod
            && "add".equals(((PsiMethod) resolve).getName())
            && ((PsiMethod) resolve).getParameterList().getParametersCount() == 1) {
          final PsiExpression[] args = methodCallExpression.getArgumentList().getExpressions();
          if (args.length == 1) {
            if (args[0] instanceof PsiCallExpression) {
              final PsiMethod method = ((PsiCallExpression) args[0]).resolveMethod();
              return method != null && !method.hasTypeParameters() && !isThrowsCompatible(method);
            }
            return true;
          }
        }
      }
    }
    return false;
  }
 private static String getIteratedValueText(PsiExpression iteratedValue) {
   return iteratedValue instanceof PsiCallExpression
           || iteratedValue instanceof PsiReferenceExpression
           || iteratedValue instanceof PsiQualifiedExpression
           || iteratedValue instanceof PsiParenthesizedExpression
       ? iteratedValue.getText()
       : "(" + iteratedValue.getText() + ")";
 }
 private static String compoundLambdaOrMethodReference(
     PsiParameter parameter,
     PsiExpression expression,
     String samQualifiedName,
     PsiType[] samParamTypes) {
   String result = "";
   final Project project = parameter.getProject();
   final JavaPsiFacade psiFacade = JavaPsiFacade.getInstance(project);
   final PsiClass functionClass =
       psiFacade.findClass(samQualifiedName, GlobalSearchScope.allScope(project));
   for (int i = 0; i < samParamTypes.length; i++) {
     if (samParamTypes[i] instanceof PsiPrimitiveType) {
       samParamTypes[i] = ((PsiPrimitiveType) samParamTypes[i]).getBoxedType(expression);
     }
   }
   final PsiClassType functionalInterfaceType =
       functionClass != null
           ? psiFacade.getElementFactory().createType(functionClass, samParamTypes)
           : null;
   final PsiParameter[] parameters = {parameter};
   final String methodReferenceText =
       LambdaCanBeMethodReferenceInspection.convertToMethodReference(
           expression, parameters, functionalInterfaceType, null);
   if (methodReferenceText != null) {
     LOG.assertTrue(functionalInterfaceType != null);
     result += "(" + functionalInterfaceType.getCanonicalText() + ")" + methodReferenceText;
   } else {
     result += parameter.getName() + " -> " + expression.getText();
   }
   return result;
 }
 private static String createMapperFunctionalExpressionText(
     PsiParameter parameter, PsiExpression expression) {
   String iteration = "";
   if (!isIdentityMapping(parameter, expression)) {
     iteration += ".map(";
     iteration +=
         compoundLambdaOrMethodReference(
             parameter,
             expression,
             "java.util.function.Function",
             new PsiType[] {parameter.getType(), expression.getType()});
     iteration += ")";
   }
   return iteration;
 }
  private static boolean isConditionDependsOnUpdatedCollections(
      PsiExpression condition, PsiExpression qualifierExpression) {
    final PsiElement collection =
        qualifierExpression instanceof PsiReferenceExpression
            ? ((PsiReferenceExpression) qualifierExpression).resolve()
            : null;
    if (collection != null) {
      return ReferencesSearch.search(collection, new LocalSearchScope(condition)).findFirst()
          != null;
    }

    final boolean[] dependsOnCollection = {false};
    condition.accept(
        new JavaRecursiveElementWalkingVisitor() {
          @Override
          public void visitMethodCallExpression(PsiMethodCallExpression expression) {
            super.visitMethodCallExpression(expression);
            final PsiExpression callQualifier =
                expression.getMethodExpression().getQualifierExpression();
            if (callQualifier == null
                || callQualifier instanceof PsiThisExpression
                    && ((PsiThisExpression) callQualifier).getQualifier() == null
                || callQualifier instanceof PsiSuperExpression
                    && ((PsiSuperExpression) callQualifier).getQualifier() == null) {
              dependsOnCollection[0] = true;
            }
          }

          @Override
          public void visitThisExpression(PsiThisExpression expression) {
            super.visitThisExpression(expression);
            if (expression.getQualifier() == null
                && expression.getParent() instanceof PsiExpressionList) {
              dependsOnCollection[0] = true;
            }
          }

          @Override
          public void visitClass(PsiClass aClass) {}

          @Override
          public void visitLambdaExpression(PsiLambdaExpression expression) {}
        });

    return dependsOnCollection[0];
  }
    @Override
    public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
      final PsiForeachStatement foreachStatement =
          PsiTreeUtil.getParentOfType(descriptor.getPsiElement(), PsiForeachStatement.class);
      if (foreachStatement != null) {
        if (!FileModificationService.getInstance().preparePsiElementForWrite(foreachStatement))
          return;
        final PsiElementFactory elementFactory = JavaPsiFacade.getElementFactory(project);
        PsiStatement body = foreachStatement.getBody();
        final PsiExpression iteratedValue = foreachStatement.getIteratedValue();
        if (body != null && iteratedValue != null) {
          final PsiParameter parameter = foreachStatement.getIterationParameter();
          final PsiIfStatement ifStatement = extractIfStatement(body);
          final PsiMethodCallExpression methodCallExpression = extractAddCall(body, ifStatement);

          if (methodCallExpression == null) return;

          if (isAddAllCall(foreachStatement, body)) {
            restoreComments(foreachStatement, body);
            final PsiExpression qualifierExpression =
                methodCallExpression.getMethodExpression().getQualifierExpression();
            final String qualifierText =
                qualifierExpression != null ? qualifierExpression.getText() : "";
            final String callText =
                StringUtil.getQualifiedName(
                    qualifierText, "addAll(" + getIteratedValueText(iteratedValue) + ");");
            PsiElement result =
                foreachStatement.replace(
                    elementFactory.createStatementFromText(callText, foreachStatement));
            reformatWhenNeeded(project, result);
            return;
          }
          final StringBuilder builder =
              new StringBuilder(getIteratedValueText(iteratedValue) + ".stream()");

          builder.append(createFiltersChainText(body, parameter, ifStatement));
          builder.append(
              createMapperFunctionalExpressionText(
                  parameter, methodCallExpression.getArgumentList().getExpressions()[0]));

          builder.append(".collect(java.util.stream.Collectors.");
          PsiElement result = null;
          try {
            final PsiExpression qualifierExpression =
                methodCallExpression.getMethodExpression().getQualifierExpression();
            if (qualifierExpression instanceof PsiReferenceExpression) {
              final PsiElement resolve = ((PsiReferenceExpression) qualifierExpression).resolve();
              if (resolve instanceof PsiVariable) {
                if (resolve instanceof PsiLocalVariable
                    && foreachStatement.equals(
                        PsiTreeUtil.skipSiblingsForward(
                            resolve.getParent(), PsiWhiteSpace.class))) {
                  final PsiExpression initializer = ((PsiVariable) resolve).getInitializer();
                  if (initializer instanceof PsiNewExpression) {
                    final PsiExpressionList argumentList =
                        ((PsiNewExpression) initializer).getArgumentList();
                    if (argumentList != null && argumentList.getExpressions().length == 0) {
                      restoreComments(foreachStatement, body);
                      final String callText =
                          builder.toString()
                              + createInitializerReplacementText(
                                  ((PsiVariable) resolve).getType(), initializer)
                              + ")";
                      result =
                          initializer.replace(
                              elementFactory.createExpressionFromText(callText, null));
                      simplifyRedundantCast(result);
                      foreachStatement.delete();
                      return;
                    }
                  }
                }
              }
            }
            restoreComments(foreachStatement, body);
            final String qualifierText =
                qualifierExpression != null ? qualifierExpression.getText() : "";
            final String callText =
                StringUtil.getQualifiedName(
                    qualifierText, "addAll(" + builder.toString() + "toList()));");
            result =
                foreachStatement.replace(
                    elementFactory.createStatementFromText(callText, foreachStatement));
            simplifyRedundantCast(result);
          } finally {
            reformatWhenNeeded(project, result);
          }
        }
      }
    }