@NotNull
  private static Specifics isFunctionalTypeMoreSpecific(
      @NotNull CandidateInfo method,
      @NotNull CandidateInfo conflict,
      PsiExpression expr,
      int functionalInterfaceIdx) {
    if (expr instanceof PsiParenthesizedExpression) {
      return isFunctionalTypeMoreSpecific(
          method,
          conflict,
          ((PsiParenthesizedExpression) expr).getExpression(),
          functionalInterfaceIdx);
    }
    if (expr instanceof PsiConditionalExpression) {
      final Specifics thenSpecifics =
          isFunctionalTypeMoreSpecific(
              method,
              conflict,
              ((PsiConditionalExpression) expr).getThenExpression(),
              functionalInterfaceIdx);
      final Specifics elseSpecifics =
          isFunctionalTypeMoreSpecific(
              method,
              conflict,
              ((PsiConditionalExpression) expr).getElseExpression(),
              functionalInterfaceIdx);
      return thenSpecifics == elseSpecifics ? thenSpecifics : Specifics.NEITHER;
    }

    if (expr instanceof PsiFunctionalExpression) {

      if (expr instanceof PsiLambdaExpression
          && !((PsiLambdaExpression) expr).hasFormalParameterTypes()) {
        return Specifics.NEITHER;
      }
      if (expr instanceof PsiMethodReferenceExpression
          && !((PsiMethodReferenceExpression) expr).isExact()) {
        return Specifics.NEITHER;
      }

      final PsiType sType = getFunctionalType(functionalInterfaceIdx, method);
      final PsiType tType = getFunctionalType(functionalInterfaceIdx, conflict);
      if (LambdaUtil.isFunctionalType(sType) && LambdaUtil.isFunctionalType(tType)) {
        final boolean specific12 =
            InferenceSession.isFunctionalTypeMoreSpecificOnExpression(sType, tType, expr);
        final boolean specific21 =
            InferenceSession.isFunctionalTypeMoreSpecificOnExpression(tType, sType, expr);
        if (specific12 && !specific21) return Specifics.FIRST;
        if (!specific12 && specific21) return Specifics.SECOND;
      }
    }
    return Specifics.NEITHER;
  }
  private static TailType getReturnTail(PsiElement position) {
    PsiElement scope = position;
    while (true) {
      if (scope instanceof PsiFile || scope instanceof PsiClassInitializer) {
        return TailType.NONE;
      }

      if (scope instanceof PsiMethod) {
        final PsiMethod method = (PsiMethod) scope;
        if (method.isConstructor() || PsiType.VOID.equals(method.getReturnType())) {
          return TailType.SEMICOLON;
        }

        return TailType.HUMBLE_SPACE_BEFORE_WORD;
      }
      if (scope instanceof PsiLambdaExpression) {
        final PsiType returnType =
            LambdaUtil.getFunctionalInterfaceReturnType(((PsiLambdaExpression) scope));
        if (PsiType.VOID.equals(returnType)) {
          return TailType.SEMICOLON;
        }
        return TailType.HUMBLE_SPACE_BEFORE_WORD;
      }
      scope = scope.getParent();
    }
  }
  @Nullable
  private PsiMethod collectExceptions(List<PsiClassType> unhandled) {
    PsiElement targetElement = null;
    PsiMethod targetMethod = null;

    final PsiElement psiElement =
        myWrongElement instanceof PsiMethodReferenceExpression
            ? myWrongElement
            : PsiTreeUtil.getParentOfType(
                myWrongElement, PsiFunctionalExpression.class, PsiMethod.class);
    if (psiElement instanceof PsiFunctionalExpression) {
      targetMethod = LambdaUtil.getFunctionalInterfaceMethod(psiElement);
      targetElement =
          psiElement instanceof PsiLambdaExpression
              ? ((PsiLambdaExpression) psiElement).getBody()
              : psiElement;
    } else if (psiElement instanceof PsiMethod) {
      targetMethod = (PsiMethod) psiElement;
      targetElement = psiElement;
    }

    if (targetElement == null || targetMethod == null || !targetMethod.getThrowsList().isPhysical())
      return null;
    List<PsiClassType> exceptions =
        getUnhandledExceptions(myWrongElement, targetElement, targetMethod);
    if (exceptions == null || exceptions.isEmpty()) return null;
    unhandled.addAll(exceptions);
    return targetMethod;
  }
 public static boolean isReceiverType(
     PsiType functionalInterfaceType,
     PsiClass containingClass,
     @Nullable PsiMethod referencedMethod) {
   final PsiClassType.ClassResolveResult resolveResult =
       PsiUtil.resolveGenericsClassInType(functionalInterfaceType);
   final MethodSignature function = LambdaUtil.getFunction(resolveResult.getElement());
   if (function != null) {
     final int interfaceMethodParamsLength = function.getParameterTypes().length;
     if (interfaceMethodParamsLength > 0) {
       final PsiType firstParamType =
           resolveResult.getSubstitutor().substitute(function.getParameterTypes()[0]);
       boolean isReceiver =
           isReceiverType(
               firstParamType,
               containingClass,
               PsiUtil.resolveGenericsClassInType(firstParamType).getSubstitutor());
       if (isReceiver) {
         if (referencedMethod == null) {
           if (interfaceMethodParamsLength == 1) return true;
           return false;
         }
         if (referencedMethod.getParameterList().getParametersCount()
             != interfaceMethodParamsLength - 1) {
           return false;
         }
         return true;
       }
     }
   }
   return false;
 }
 @Nullable
 private static PsiMethod getScopeMethod(PsiElement block) {
   PsiElement parent = block.getParent();
   if (parent instanceof PsiMethod) return (PsiMethod) parent;
   if (parent instanceof PsiLambdaExpression)
     return LambdaUtil.getFunctionalInterfaceMethod(
         ((PsiLambdaExpression) parent).getFunctionalInterfaceType());
   return null;
 }
 @Nullable
 public static HighlightInfo checkFunctionalInterface(
     @NotNull PsiAnnotation annotation, @NotNull LanguageLevel languageLevel) {
   final String errorMessage = LambdaUtil.checkFunctionalInterface(annotation, languageLevel);
   if (errorMessage != null) {
     return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR)
         .range(annotation)
         .descriptionAndTooltip(errorMessage)
         .create();
   }
   return null;
 }
 private static boolean hasReceiver(
     @NotNull PsiMethodReferenceExpression methodRef,
     @NotNull PsiMethod method,
     PsiType functionalInterfaceType) {
   final PsiClassType.ClassResolveResult resolveResult =
       PsiUtil.resolveGenericsClassInType(functionalInterfaceType);
   final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(resolveResult);
   final MethodSignature signature =
       interfaceMethod != null
           ? interfaceMethod.getSignature(
               LambdaUtil.getSubstitutor(interfaceMethod, resolveResult))
           : null;
   if (signature == null) {
     return false;
   }
   final PsiType[] parameterTypes = signature.getParameterTypes();
   final QualifierResolveResult qualifierResolveResult = getQualifierResolveResult(methodRef);
   return (method.getParameterList().getParametersCount() + 1 == parameterTypes.length
           || method.isVarArgs()
               && parameterTypes.length > 0
               && !method.hasModifierProperty(PsiModifier.STATIC))
       && hasReceiver(parameterTypes, qualifierResolveResult, methodRef);
 }
  public static String checkReturnType(
      PsiMethodReferenceExpression expression,
      JavaResolveResult result,
      PsiType functionalInterfaceType) {
    final PsiElement resolve = result.getElement();
    if (resolve instanceof PsiMethod) {
      final PsiClass containingClass = ((PsiMethod) resolve).getContainingClass();
      LOG.assertTrue(containingClass != null);
      PsiSubstitutor subst = result.getSubstitutor();
      PsiClass qContainingClass = getQualifierResolveResult(expression).getContainingClass();
      if (qContainingClass != null
          && isReceiverType(functionalInterfaceType, containingClass, (PsiMethod) resolve)) {
        subst = TypeConversionUtil.getClassSubstitutor(containingClass, qContainingClass, subst);
        LOG.assertTrue(subst != null);
      }

      final PsiType interfaceReturnType =
          LambdaUtil.getFunctionalInterfaceReturnType(functionalInterfaceType);

      PsiType returnType =
          PsiTypesUtil.patchMethodGetClassReturnType(
              expression,
              expression,
              (PsiMethod) resolve,
              null,
              PsiUtil.getLanguageLevel(expression));
      if (returnType == null) {
        returnType = ((PsiMethod) resolve).getReturnType();
      }
      PsiType methodReturnType = subst.substitute(returnType);
      if (interfaceReturnType != null && interfaceReturnType != PsiType.VOID) {
        if (methodReturnType == null) {
          methodReturnType =
              JavaPsiFacade.getElementFactory(expression.getProject())
                  .createType(containingClass, subst);
        }
        if (!TypeConversionUtil.isAssignable(interfaceReturnType, methodReturnType, false)) {
          return "Bad return type in method reference: cannot convert "
              + methodReturnType.getCanonicalText()
              + " to "
              + interfaceReturnType.getCanonicalText();
        }
      }
    }
    return null;
  }
예제 #9
0
 @Override
 public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
   final PsiElement element = descriptor.getPsiElement();
   if (element != null) {
     if (!FileModificationService.getInstance().preparePsiElementForWrite(element)) return;
     final PsiLambdaExpression lambdaExpression =
         PsiTreeUtil.getParentOfType(element, PsiLambdaExpression.class);
     if (lambdaExpression != null) {
       final PsiElement body = lambdaExpression.getBody();
       if (body != null) {
         PsiExpression expression = LambdaUtil.extractSingleExpressionFromBody(body);
         if (expression != null) {
           body.replace(expression);
         }
       }
     }
   }
 }
예제 #10
0
  @Override
  public boolean reduce(InferenceSession session, List<ConstraintFormula> constraints) {
    if (!LambdaUtil.isFunctionalType(myT)) {
      return false;
    }

    final PsiType groundTargetType =
        FunctionalInterfaceParameterizationUtil.getGroundTargetType(myT);
    final PsiClassType.ClassResolveResult classResolveResult =
        PsiUtil.resolveGenericsClassInType(groundTargetType);
    final PsiMethod interfaceMethod = LambdaUtil.getFunctionalInterfaceMethod(classResolveResult);
    if (interfaceMethod == null) {
      return false;
    }

    final PsiSubstitutor substitutor =
        LambdaUtil.getSubstitutor(interfaceMethod, classResolveResult);
    final PsiParameter[] targetParameters = interfaceMethod.getParameterList().getParameters();
    final PsiType interfaceMethodReturnType = interfaceMethod.getReturnType();
    final PsiType returnType = substitutor.substitute(interfaceMethodReturnType);
    final PsiType[] typeParameters = myExpression.getTypeParameters();

    final PsiMethodReferenceUtil.QualifierResolveResult qualifierResolveResult =
        PsiMethodReferenceUtil.getQualifierResolveResult(myExpression);

    if (!myExpression.isExact()) {
      for (PsiParameter parameter : targetParameters) {
        if (!session.isProperType(substitutor.substitute(parameter.getType()))) {
          return false;
        }
      }
    } else {
      final PsiMember applicableMember = myExpression.getPotentiallyApplicableMember();
      LOG.assertTrue(applicableMember != null);

      final PsiClass applicableMemberContainingClass = applicableMember.getContainingClass();
      final PsiClass containingClass = qualifierResolveResult.getContainingClass();

      PsiSubstitutor psiSubstitutor = qualifierResolveResult.getSubstitutor();
      psiSubstitutor =
          applicableMemberContainingClass == null
                  || containingClass == null
                  || myExpression.isConstructor()
              ? psiSubstitutor
              : TypeConversionUtil.getSuperClassSubstitutor(
                  applicableMemberContainingClass, containingClass, psiSubstitutor);

      PsiType applicableMethodReturnType =
          applicableMember instanceof PsiMethod
              ? ((PsiMethod) applicableMember).getReturnType()
              : null;
      int idx = 0;
      for (PsiTypeParameter param :
          ((PsiTypeParameterListOwner) applicableMember).getTypeParameters()) {
        if (idx < typeParameters.length) {
          psiSubstitutor = psiSubstitutor.put(param, typeParameters[idx++]);
        }
      }
      final PsiParameter[] parameters =
          applicableMember instanceof PsiMethod
              ? ((PsiMethod) applicableMember).getParameterList().getParameters()
              : PsiParameter.EMPTY_ARRAY;
      if (targetParameters.length == parameters.length + 1) {
        specialCase(session, constraints, substitutor, targetParameters, true);
        for (int i = 1; i < targetParameters.length; i++) {
          constraints.add(
              new TypeCompatibilityConstraint(
                  session.substituteWithInferenceVariables(
                      psiSubstitutor.substitute(parameters[i - 1].getType())),
                  substitutor.substitute(targetParameters[i].getType())));
        }
      } else if (targetParameters.length == parameters.length) {
        for (int i = 0; i < targetParameters.length; i++) {
          constraints.add(
              new TypeCompatibilityConstraint(
                  session.substituteWithInferenceVariables(
                      psiSubstitutor.substitute(parameters[i].getType())),
                  substitutor.substitute(targetParameters[i].getType())));
        }
      } else {
        return false;
      }
      if (returnType != PsiType.VOID && returnType != null) {
        if (applicableMethodReturnType == PsiType.VOID) {
          return false;
        }

        if (applicableMethodReturnType != null) {
          constraints.add(
              new TypeCompatibilityConstraint(
                  returnType,
                  session.substituteWithInferenceVariables(
                      psiSubstitutor.substitute(applicableMethodReturnType))));
        } else if (applicableMember instanceof PsiClass
            || applicableMember instanceof PsiMethod
                && ((PsiMethod) applicableMember).isConstructor()) {
          final PsiElementFactory elementFactory =
              JavaPsiFacade.getElementFactory(applicableMember.getProject());
          if (containingClass != null) {
            final PsiType classType =
                session.substituteWithInferenceVariables(
                    elementFactory.createType(containingClass, psiSubstitutor));
            constraints.add(new TypeCompatibilityConstraint(returnType, classType));
          }
        }
      }
      return true;
    }

    final Map<PsiElement, PsiType> map = LambdaUtil.getFunctionalTypeMap();
    final PsiType added = map.put(myExpression, session.startWithFreshVars(groundTargetType));
    final JavaResolveResult resolve;
    try {
      resolve = myExpression.advancedResolve(true);
    } finally {
      if (added == null) {
        map.remove(myExpression);
      }
    }
    final PsiElement element = resolve.getElement();
    if (element == null) {
      return false;
    }

    if (PsiType.VOID.equals(returnType) || returnType == null) {
      return true;
    }

    if (element instanceof PsiMethod) {
      final PsiMethod method = (PsiMethod) element;
      final PsiType referencedMethodReturnType;
      final PsiClass containingClass = method.getContainingClass();
      LOG.assertTrue(containingClass != null, method);
      PsiClass qContainingClass = qualifierResolveResult.getContainingClass();
      PsiSubstitutor psiSubstitutor = qualifierResolveResult.getSubstitutor();
      if (qContainingClass != null) {
        if (PsiUtil.isRawSubstitutor(qContainingClass, psiSubstitutor)) {
          psiSubstitutor = PsiSubstitutor.EMPTY;
        }
        if (qContainingClass.isInheritor(containingClass, true)) {
          psiSubstitutor =
              TypeConversionUtil.getClassSubstitutor(
                  containingClass, qContainingClass, PsiSubstitutor.EMPTY);
          LOG.assertTrue(psiSubstitutor != null);
        }
      }

      if (method.isConstructor()) {
        referencedMethodReturnType =
            JavaPsiFacade.getElementFactory(method.getProject())
                .createType(containingClass, PsiSubstitutor.EMPTY);
      } else {
        referencedMethodReturnType = method.getReturnType();
      }
      LOG.assertTrue(referencedMethodReturnType != null, method);

      if (!PsiTreeUtil.isContextAncestor(containingClass, myExpression, false)
          || PsiUtil.getEnclosingStaticElement(myExpression, containingClass) != null) {
        session.initBounds(myExpression, containingClass.getTypeParameters());
      }

      session.initBounds(myExpression, method.getTypeParameters());

      // if i) the method reference elides NonWildTypeArguments,
      //  ii) the compile-time declaration is a generic method, and
      // iii) the return type of the compile-time declaration mentions at least one of the method's
      // type parameters;
      if (typeParameters.length == 0 && method.getTypeParameters().length > 0) {
        final PsiClass interfaceClass = classResolveResult.getElement();
        LOG.assertTrue(interfaceClass != null);
        if (PsiPolyExpressionUtil.mentionsTypeParameters(
            referencedMethodReturnType, ContainerUtil.newHashSet(method.getTypeParameters()))) {
          // the constraint reduces to the bound set B3 which would be used to determine the method
          // reference's invocation type
          // when targeting the return type of the function type, as defined in 18.5.2.
          session.collectApplicabilityConstraints(
              myExpression, ((MethodCandidateInfo) resolve), groundTargetType);
          session.registerReturnTypeConstraints(referencedMethodReturnType, returnType);
          return true;
        }
      }

      if (PsiType.VOID.equals(referencedMethodReturnType)) {
        return false;
      }

      int idx = 0;
      for (PsiTypeParameter param : method.getTypeParameters()) {
        if (idx < typeParameters.length) {
          psiSubstitutor = psiSubstitutor.put(param, typeParameters[idx++]);
        }
      }

      final PsiParameter[] parameters = method.getParameterList().getParameters();
      if (targetParameters.length == parameters.length + 1
          && !method.isVarArgs()
          && PsiPolyExpressionUtil.mentionsTypeParameters(
              referencedMethodReturnType,
              ContainerUtil.newHashSet(
                  containingClass.getTypeParameters()))) { // todo specification bug?
        specialCase(session, constraints, substitutor, targetParameters, false);
      }
      constraints.add(
          new TypeCompatibilityConstraint(
              returnType,
              session.substituteWithInferenceVariables(
                  psiSubstitutor.substitute(referencedMethodReturnType))));
    }

    return true;
  }
  static PsiSubstitutor infer(
      @NotNull PsiTypeParameter[] typeParameters,
      @NotNull PsiParameter[] parameters,
      @NotNull PsiExpression[] arguments,
      @NotNull PsiSubstitutor partialSubstitutor,
      @NotNull final PsiElement parent,
      @NotNull final ParameterTypeInferencePolicy policy) {
    if (parent instanceof PsiCall) {
      final PsiExpressionList argumentList = ((PsiCall) parent).getArgumentList();
      final MethodCandidateInfo.CurrentCandidateProperties properties =
          MethodCandidateInfo.getCurrentMethod(argumentList);
      // overload resolution can't depend on outer call => should not traverse to top
      if (properties != null
          && !properties.isApplicabilityCheck()
          &&
          // in order to to avoid caching of candidates's errors on parent (!) , so check for
          // overload resolution is left here
          // But overload resolution can depend on type of lambda parameter. As it can't depend on
          // lambda body,
          // traversing down would stop at lambda level and won't take into account overloaded
          // method
          !MethodCandidateInfo.ourOverloadGuard.currentStack().contains(argumentList)) {
        final PsiCall topLevelCall =
            PsiResolveHelper.ourGraphGuard.doPreventingRecursion(
                parent,
                false,
                new Computable<PsiCall>() {
                  @Override
                  public PsiCall compute() {
                    if (parent instanceof PsiExpression
                        && !PsiPolyExpressionUtil.isPolyExpression((PsiExpression) parent)) {
                      return null;
                    }
                    return LambdaUtil.treeWalkUp(parent);
                  }
                });
        if (topLevelCall != null) {

          InferenceSession session;
          if (MethodCandidateInfo.isOverloadCheck()
              || !PsiDiamondType.ourDiamondGuard.currentStack().isEmpty()
              || LambdaUtil.isLambdaParameterCheck()) {
            session = startTopLevelInference(topLevelCall, policy);
          } else {
            session =
                CachedValuesManager.getCachedValue(
                    topLevelCall,
                    new CachedValueProvider<InferenceSession>() {
                      @Nullable
                      @Override
                      public Result<InferenceSession> compute() {
                        return new Result<InferenceSession>(
                            startTopLevelInference(topLevelCall, policy),
                            PsiModificationTracker.MODIFICATION_COUNT);
                      }
                    });

            if (session != null) {
              // reject cached top level session if it was based on wrong candidate: check nested
              // session if candidate (it's type parameters) are the same
              // such situations are avoided when overload resolution is performed
              // (MethodCandidateInfo.isOverloadCheck above)
              // but situations when client code iterates through
              // PsiResolveHelper.getReferencedMethodCandidates or similar are impossible to guess
              final Map<PsiElement, InferenceSession> sessions =
                  session.getInferenceSessionContainer().myNestedSessions;
              final InferenceSession childSession = sessions.get(parent);
              if (childSession != null) {
                for (PsiTypeParameter parameter : typeParameters) {
                  if (!childSession
                      .getInferenceSubstitution()
                      .getSubstitutionMap()
                      .containsKey(parameter)) {
                    session = startTopLevelInference(topLevelCall, policy);
                    break;
                  }
                }
              }
            }
          }

          if (session != null) {
            final PsiSubstitutor childSubstitutor =
                inferNested(
                    typeParameters,
                    parameters,
                    arguments,
                    partialSubstitutor,
                    (PsiCall) parent,
                    policy,
                    properties,
                    session);
            if (childSubstitutor != null) return childSubstitutor;
          } else if (topLevelCall instanceof PsiMethodCallExpression) {
            return new InferenceSession(
                    typeParameters, partialSubstitutor, parent.getManager(), parent, policy)
                .prepareSubstitution();
          }
        }
      }
    }

    final InferenceSession inferenceSession =
        new InferenceSession(
            typeParameters, partialSubstitutor, parent.getManager(), parent, policy);
    inferenceSession.initExpressionConstraints(parameters, arguments, parent);
    return inferenceSession.infer(parameters, arguments, parent);
  }
  private static PsiSubstitutor inferNested(
      final PsiTypeParameter[] typeParameters,
      @NotNull final PsiParameter[] parameters,
      @NotNull final PsiExpression[] arguments,
      final PsiSubstitutor partialSubstitutor,
      @NotNull final PsiCall parent,
      @NotNull final ParameterTypeInferencePolicy policy,
      final MethodCandidateInfo.CurrentCandidateProperties properties,
      final InferenceSession parentSession) {
    final CompoundInitialState compoundInitialState = createState(parentSession);
    InitialInferenceState initialInferenceState = compoundInitialState.getInitialState(parent);
    if (initialInferenceState != null) {
      final InferenceSession childSession = new InferenceSession(initialInferenceState);
      final List<String> errorMessages = parentSession.getIncompatibleErrorMessages();
      if (errorMessages != null) {
        return childSession.prepareSubstitution();
      }
      return childSession.collectAdditionalAndInfer(
          parameters, arguments, properties, compoundInitialState.getInitialSubstitutor());
    }

    // we do not investigate lambda return expressions when lambda's return type is already inferred
    // (proper)
    // this way all calls from lambda's return expressions won't appear in nested sessions
    else {
      PsiElement gParent = PsiUtil.skipParenthesizedExprUp(parent.getParent());
      // find the nearest parent which appears in the map and start inference with a provided target
      // type for a nested lambda
      while (true) {
        if (gParent instanceof PsiReturnStatement) { // process code block lambda
          final PsiElement returnContainer = gParent.getParent();
          if (returnContainer instanceof PsiCodeBlock) {
            gParent = returnContainer.getParent();
          }
        }
        if (gParent instanceof PsiLambdaExpression) {
          final PsiCall call = PsiTreeUtil.getParentOfType(gParent, PsiCall.class);
          if (call != null) {
            initialInferenceState = compoundInitialState.getInitialState(call);
            if (initialInferenceState != null) {
              final int idx = LambdaUtil.getLambdaIdx(call.getArgumentList(), gParent);
              final PsiMethod method = call.resolveMethod();
              if (method != null && idx > -1) {
                final PsiType parameterType =
                    PsiTypesUtil.getParameterType(
                        method.getParameterList().getParameters(), idx, true);
                final PsiType parameterTypeInTermsOfSession =
                    initialInferenceState.getInferenceSubstitutor().substitute(parameterType);
                final PsiType lambdaTargetType =
                    compoundInitialState
                        .getInitialSubstitutor()
                        .substitute(parameterTypeInTermsOfSession);
                return LambdaUtil.performWithLambdaTargetType(
                    (PsiLambdaExpression) gParent,
                    lambdaTargetType,
                    new Producer<PsiSubstitutor>() {
                      @Nullable
                      @Override
                      public PsiSubstitutor produce() {
                        if (call.equals(PsiTreeUtil.getParentOfType(parent, PsiCall.class, true))) {
                          // parent was mentioned in the top inference session
                          // just proceed with the target type
                          final InferenceSession inferenceSession =
                              new InferenceSession(
                                  typeParameters,
                                  partialSubstitutor,
                                  parent.getManager(),
                                  parent,
                                  policy);
                          inferenceSession.initExpressionConstraints(parameters, arguments, parent);
                          return inferenceSession.infer(parameters, arguments, parent);
                        }
                        // one of the grand parents were found in the top inference session
                        // start from it as it is the top level call
                        final InferenceSession sessionInsideLambda =
                            startTopLevelInference(call, policy);
                        return inferNested(
                            typeParameters,
                            parameters,
                            arguments,
                            partialSubstitutor,
                            parent,
                            policy,
                            properties,
                            sessionInsideLambda);
                      }
                    });
              }
            } else {
              gParent = PsiUtil.skipParenthesizedExprUp(call.getParent());
              continue;
            }
          }
        }
        break;
      }
    }
    return null;
  }
 @Nullable
 @Override
 public PsiType getFunctionalInterfaceType() {
   return FunctionalInterfaceParameterizationUtil.getGroundTargetType(
       LambdaUtil.getFunctionalInterfaceType(this, true), this);
 }
  private Specifics isMoreSpecific(
      @NotNull MethodCandidateInfo info1,
      @NotNull MethodCandidateInfo info2,
      @MethodCandidateInfo.ApplicabilityLevelConstant int applicabilityLevel,
      @NotNull LanguageLevel languageLevel) {
    PsiMethod method1 = info1.getElement();
    PsiMethod method2 = info2.getElement();
    final PsiClass class1 = method1.getContainingClass();
    final PsiClass class2 = method2.getContainingClass();

    final PsiParameter[] params1 = method1.getParameterList().getParameters();
    final PsiParameter[] params2 = method2.getParameterList().getParameters();

    final PsiTypeParameter[] typeParameters1 = method1.getTypeParameters();
    final PsiTypeParameter[] typeParameters2 = method2.getTypeParameters();
    final PsiSubstitutor classSubstitutor1 =
        info1.getSubstitutor(false); // substitutions for method type parameters will be ignored
    final PsiSubstitutor classSubstitutor2 = info2.getSubstitutor(false);

    final int max = Math.max(params1.length, params2.length);
    PsiType[] types1 = PsiType.createArray(max);
    PsiType[] types2 = PsiType.createArray(max);
    final boolean varargsPosition =
        applicabilityLevel == MethodCandidateInfo.ApplicabilityLevel.VARARGS;
    for (int i = 0; i < max; i++) {
      ProgressManager.checkCanceled();
      PsiType type1 =
          params1.length > 0 ? params1[Math.min(i, params1.length - 1)].getType() : null;
      PsiType type2 =
          params2.length > 0 ? params2[Math.min(i, params2.length - 1)].getType() : null;
      if (varargsPosition) {
        if (type1 instanceof PsiEllipsisType
            && type2 instanceof PsiEllipsisType
            && params1.length == params2.length
            && class1 != null
            && (!JavaVersionService.getInstance().isAtLeast(class1, JavaSdkVersion.JDK_1_7)
                || ((PsiArrayType) type1)
                    .getComponentType()
                    .equalsToText(CommonClassNames.JAVA_LANG_OBJECT)
                || ((PsiArrayType) type2)
                    .getComponentType()
                    .equalsToText(CommonClassNames.JAVA_LANG_OBJECT))) {
          type1 = ((PsiEllipsisType) type1).toArrayType();
          type2 = ((PsiEllipsisType) type2).toArrayType();
        } else {
          type1 =
              type1 instanceof PsiEllipsisType ? ((PsiArrayType) type1).getComponentType() : type1;
          type2 =
              type2 instanceof PsiEllipsisType ? ((PsiArrayType) type2).getComponentType() : type2;
        }
      }

      types1[i] = type1;
      types2[i] = type2;
    }

    boolean sameBoxing = true;
    int[] boxingHappened = new int[2];
    for (int i = 0; i < types1.length; i++) {
      ProgressManager.checkCanceled();
      PsiType type1 = classSubstitutor1.substitute(types1[i]);
      PsiType type2 = classSubstitutor2.substitute(types2[i]);
      PsiType argType = i < getActualParameterTypes().length ? getActualParameterTypes()[i] : null;

      boolean boxingInFirst = false;
      if (isBoxingHappened(argType, type1, languageLevel)) {
        boxingHappened[0] += 1;
        boxingInFirst = true;
      }

      boolean boxingInSecond = false;
      if (isBoxingHappened(argType, type2, languageLevel)) {
        boxingHappened[1] += 1;
        boxingInSecond = true;
      }
      sameBoxing &= boxingInFirst == boxingInSecond;
    }
    if (boxingHappened[0] == 0 && boxingHappened[1] > 0) return Specifics.FIRST;
    if (boxingHappened[0] > 0 && boxingHappened[1] == 0) return Specifics.SECOND;

    if (sameBoxing) {
      final PsiSubstitutor siteSubstitutor1 = info1.getSiteSubstitutor();
      final PsiSubstitutor siteSubstitutor2 = info2.getSiteSubstitutor();

      final PsiType[] types2AtSite = typesAtSite(types2, siteSubstitutor2);
      final PsiType[] types1AtSite = typesAtSite(types1, siteSubstitutor1);

      final PsiSubstitutor methodSubstitutor1 =
          calculateMethodSubstitutor(
              typeParameters1, method1, siteSubstitutor1, types1, types2AtSite, languageLevel);
      boolean applicable12 =
          isApplicableTo(
              types2AtSite, method1, languageLevel, varargsPosition, methodSubstitutor1, method2);

      final PsiSubstitutor methodSubstitutor2 =
          calculateMethodSubstitutor(
              typeParameters2, method2, siteSubstitutor2, types2, types1AtSite, languageLevel);
      boolean applicable21 =
          isApplicableTo(
              types1AtSite, method2, languageLevel, varargsPosition, methodSubstitutor2, method1);

      if (!myLanguageLevel.isAtLeast(LanguageLevel.JDK_1_8)) {
        final boolean typeArgsApplicable12 =
            GenericsUtil.isTypeArgumentsApplicable(
                typeParameters1, methodSubstitutor1, myArgumentsList, !applicable21);
        final boolean typeArgsApplicable21 =
            GenericsUtil.isTypeArgumentsApplicable(
                typeParameters2, methodSubstitutor2, myArgumentsList, !applicable12);

        if (!typeArgsApplicable12) {
          applicable12 = false;
        }

        if (!typeArgsApplicable21) {
          applicable21 = false;
        }
      }

      if (applicable12 || applicable21) {

        if (applicable12 && !applicable21) return Specifics.SECOND;
        if (applicable21 && !applicable12) return Specifics.FIRST;

        final boolean abstract1 = method1.hasModifierProperty(PsiModifier.ABSTRACT);
        final boolean abstract2 = method2.hasModifierProperty(PsiModifier.ABSTRACT);
        if (abstract1 && !abstract2) {
          return Specifics.SECOND;
        }
        if (abstract2 && !abstract1) {
          return Specifics.FIRST;
        }
      }

      if (languageLevel.isAtLeast(LanguageLevel.JDK_1_8)
          && myArgumentsList instanceof PsiExpressionList
          && (typeParameters1.length == 0 || typeParameters2.length == 0)) {
        boolean toCompareFunctional = false;
        if (types1.length > 0 && types2.length > 0) {
          for (int i = 0; i < getActualParametersLength(); i++) {
            final PsiType type1 = types1[Math.min(i, types1.length - 1)];
            final PsiType type2 = types2[Math.min(i, types2.length - 1)];
            // from 15.12.2.5 Choosing the Most Specific Method
            // In addition, a functional interface type S is more specific than a functional
            // interface type T for an expression exp
            // if T is not a subtype of S and one of the following conditions apply.
            if (LambdaUtil.isFunctionalType(type1)
                && !TypeConversionUtil.erasure(type1).isAssignableFrom(type2)
                && LambdaUtil.isFunctionalType(type2)
                && !TypeConversionUtil.erasure(type2).isAssignableFrom(type1)) {
              types1AtSite[Math.min(i, types1.length - 1)] = PsiType.NULL;
              types2AtSite[Math.min(i, types2.length - 1)] = PsiType.NULL;
              toCompareFunctional = true;
            }
          }
        }

        if (toCompareFunctional) {
          final boolean applicable12ignoreFunctionalType =
              isApplicableTo(
                  types2AtSite,
                  method1,
                  languageLevel,
                  varargsPosition,
                  calculateMethodSubstitutor(
                      typeParameters1,
                      method1,
                      siteSubstitutor1,
                      types1,
                      types2AtSite,
                      languageLevel),
                  null);
          final boolean applicable21ignoreFunctionalType =
              isApplicableTo(
                  types1AtSite,
                  method2,
                  languageLevel,
                  varargsPosition,
                  calculateMethodSubstitutor(
                      typeParameters2,
                      method2,
                      siteSubstitutor2,
                      types2,
                      types1AtSite,
                      languageLevel),
                  null);

          if (applicable12ignoreFunctionalType || applicable21ignoreFunctionalType) {
            Specifics specifics = null;
            for (int i = 0; i < getActualParametersLength(); i++) {
              if (types1AtSite[Math.min(i, types1.length - 1)] == PsiType.NULL
                  && types2AtSite[Math.min(i, types2.length - 1)] == PsiType.NULL) {
                Specifics specific =
                    isFunctionalTypeMoreSpecific(
                        info1, info2, ((PsiExpressionList) myArgumentsList).getExpressions()[i], i);
                if (specific == Specifics.NEITHER) {
                  specifics = Specifics.NEITHER;
                  break;
                }

                if (specifics == null) {
                  specifics = specific;
                } else if (specifics != specific) {
                  specifics = Specifics.NEITHER;
                  break;
                }
              }
            }

            if (!applicable12ignoreFunctionalType && applicable21ignoreFunctionalType) {
              return specifics == Specifics.FIRST ? Specifics.FIRST : Specifics.NEITHER;
            }

            if (!applicable21ignoreFunctionalType && applicable12ignoreFunctionalType) {
              return specifics == Specifics.SECOND ? Specifics.SECOND : Specifics.NEITHER;
            }

            return specifics;
          }
        }
      }
    } else if (varargsPosition) {
      final PsiType lastParamType1 = classSubstitutor1.substitute(types1[types1.length - 1]);
      final PsiType lastParamType2 = classSubstitutor2.substitute(types2[types1.length - 1]);
      final boolean assignable1 = TypeConversionUtil.isAssignable(lastParamType2, lastParamType1);
      final boolean assignable2 = TypeConversionUtil.isAssignable(lastParamType1, lastParamType2);
      if (assignable1 && !assignable2) {
        return Specifics.FIRST;
      }
      if (assignable2 && !assignable1) {
        return Specifics.SECOND;
      }
    }

    if (class1 != class2) {
      if (class2.isInheritor(class1, true) || class1.isInterface() && !class2.isInterface()) {
        if (MethodSignatureUtil.isSubsignature(
            method1.getSignature(info1.getSubstitutor(false)),
            method2.getSignature(info2.getSubstitutor(false)))) {
          return Specifics.SECOND;
        } else if (method1.hasModifierProperty(PsiModifier.STATIC)
            && method2.hasModifierProperty(PsiModifier.STATIC)
            && boxingHappened[0] == 0) {
          return Specifics.SECOND;
        }
      } else if (MethodSignatureUtil.areErasedParametersEqual(
              method1.getSignature(PsiSubstitutor.EMPTY),
              method2.getSignature(PsiSubstitutor.EMPTY))
          && MethodSignatureUtil.isSubsignature(
              method2.getSignature(info2.getSubstitutor(false)),
              method1.getSignature(info1.getSubstitutor(false)))) {
        return Specifics.FIRST;
      } else if (class1.isInheritor(class2, true) || class2.isInterface()) {
        if (method1.hasModifierProperty(PsiModifier.STATIC)
            && method2.hasModifierProperty(PsiModifier.STATIC)
            && boxingHappened[0] == 0) {
          return Specifics.FIRST;
        }
      }
    }

    final boolean raw1 = PsiUtil.isRawSubstitutor(method1, classSubstitutor1);
    final boolean raw2 = PsiUtil.isRawSubstitutor(method2, classSubstitutor2);
    if (raw1 ^ raw2) {
      return raw1 ? Specifics.SECOND : Specifics.FIRST;
    }

    final boolean varargs1 = info1.isVarargs();
    final boolean varargs2 = info2.isVarargs();
    if (varargs1 ^ varargs2) {
      return varargs1 ? Specifics.SECOND : Specifics.FIRST;
    }

    return Specifics.NEITHER;
  }