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;
 }
  @Nullable
  public static PsiType getSubstitutedType(@Nullable PsiParameter parameter) {
    if (parameter == null) return null;

    final PsiType type = getType(parameter);

    if (type instanceof PsiArrayType) {
      return type;
    }

    final PsiClassType.ClassResolveResult result = PsiUtil.resolveGenericsClassInType(type);
    final PsiClass psiClass = result.getElement();
    if (psiClass == null) return type;

    final Set<PsiTypeParameter> usedTypeParameters = new HashSet<PsiTypeParameter>();
    RefactoringUtil.collectTypeParameters(usedTypeParameters, parameter);
    for (Iterator<PsiTypeParameter> iterator = usedTypeParameters.iterator();
        iterator.hasNext(); ) {
      PsiTypeParameter usedTypeParameter = iterator.next();
      if (parameter.getDeclarationScope() != usedTypeParameter.getOwner()) {
        iterator.remove();
      }
    }

    PsiSubstitutor subst = PsiSubstitutor.EMPTY;
    for (PsiTypeParameter usedTypeParameter : usedTypeParameters) {
      subst =
          subst.put(usedTypeParameter, TypeConversionUtil.typeParameterErasure(usedTypeParameter));
    }

    PsiSubstitutor substitutor = PsiSubstitutor.EMPTY;
    final Map<PsiTypeParameter, PsiType> typeMap = result.getSubstitutor().getSubstitutionMap();
    for (PsiTypeParameter typeParameter : typeMap.keySet()) {
      final PsiType psiType = typeMap.get(typeParameter);
      substitutor =
          substitutor.put(typeParameter, psiType != null ? subst.substitute(psiType) : null);
    }

    if (psiClass instanceof PsiTypeParameter) {
      return subst.substitute((PsiTypeParameter) psiClass);
    } else {
      return JavaPsiFacade.getElementFactory(parameter.getProject())
          .createType(psiClass, substitutor);
    }
  }
 private static boolean isTrivial(PsiStatement body, PsiParameter parameter) {
   final PsiIfStatement ifStatement = extractIfStatement(body);
   // filter
   if (ifStatement != null) {
     return false;
   }
   // method reference
   final PsiCallExpression callExpression =
       LambdaCanBeMethodReferenceInspection.canBeMethodReferenceProblem(
           body instanceof PsiBlockStatement ? ((PsiBlockStatement) body).getCodeBlock() : body,
           new PsiParameter[] {parameter},
           createDefaultConsumerType(parameter.getProject(), parameter));
   if (callExpression == null) {
     return true;
   }
   final PsiMethod method = callExpression.resolveMethod();
   return method != null && isThrowsCompatible(method);
 }