private static void simplifyRedundantCast(PsiElement result) {
final PsiMethodReferenceExpression methodReferenceExpression =
PsiTreeUtil.findChildOfType(result, PsiMethodReferenceExpression.class);
if (methodReferenceExpression != null) {
final PsiElement parent = methodReferenceExpression.getParent();
if (parent instanceof PsiTypeCastExpression) {
if (RedundantCastUtil.isCastRedundant((PsiTypeCastExpression) parent)) {
final PsiExpression operand = ((PsiTypeCastExpression) parent).getOperand();
LOG.assertTrue(operand != null);
parent.replace(operand);
}
}
}
}
public static boolean isValidQualifier(PsiMethodReferenceExpression expression) {
final PsiElement referenceNameElement = expression.getReferenceNameElement();
if (referenceNameElement instanceof PsiKeyword) {
final PsiElement qualifier = expression.getQualifier();
if (qualifier instanceof PsiTypeElement) {
return true;
}
if (qualifier instanceof PsiReferenceExpression
&& ((PsiReferenceExpression) qualifier).resolve() instanceof PsiClass) {
return true;
}
}
return false;
}
public static boolean isStaticallyReferenced(
@NotNull PsiMethodReferenceExpression methodReferenceExpression) {
final PsiExpression qualifierExpression = methodReferenceExpression.getQualifierExpression();
if (qualifierExpression != null) {
return qualifierExpression instanceof PsiReferenceExpression
&& ((PsiReferenceExpression) qualifierExpression).resolve() instanceof PsiClass;
}
return true;
}
@Nullable
public static PsiType getQualifierType(PsiMethodReferenceExpression expression) {
PsiType qualifierType = null;
final PsiTypeElement typeElement = expression.getQualifierType();
if (typeElement != null) {
qualifierType = typeElement.getType();
} else {
final PsiElement qualifier = expression.getQualifier();
if (qualifier instanceof PsiExpression) {
qualifierType = ((PsiExpression) qualifier).getType();
}
}
if (qualifierType == null) {
final QualifierResolveResult qualifierResolveResult = getQualifierResolveResult(expression);
final PsiClass containingClass = qualifierResolveResult.getContainingClass();
if (containingClass == null) {
return null;
}
qualifierType =
JavaPsiFacade.getElementFactory(expression.getProject()).createType(containingClass);
}
return qualifierType;
}
public static boolean hasReceiver(
PsiType[] parameterTypes,
QualifierResolveResult qualifierResolveResult,
PsiMethodReferenceExpression methodRef) {
if (parameterTypes.length > 0
&& !methodRef.isConstructor()
&& isReceiverType(
parameterTypes[0],
qualifierResolveResult.getContainingClass(),
qualifierResolveResult.getSubstitutor())
&& isStaticallyReferenced(methodRef)) {
return true;
}
return false;
}
@NotNull
public static QualifierResolveResult getQualifierResolveResult(
@NotNull PsiMethodReferenceExpression methodReferenceExpression) {
PsiClass containingClass = null;
PsiSubstitutor substitutor = PsiSubstitutor.EMPTY;
final PsiExpression expression = methodReferenceExpression.getQualifierExpression();
if (expression != null) {
final PsiType expressionType = getExpandedType(expression.getType(), expression);
PsiClassType.ClassResolveResult result = PsiUtil.resolveGenericsClassInType(expressionType);
containingClass = result.getElement();
if (containingClass != null) {
substitutor = result.getSubstitutor();
}
if (containingClass == null && expression instanceof PsiReferenceExpression) {
final JavaResolveResult resolveResult =
((PsiReferenceExpression) expression).advancedResolve(false);
final PsiElement resolve = resolveResult.getElement();
if (resolve instanceof PsiClass) {
containingClass = (PsiClass) resolve;
substitutor = resolveResult.getSubstitutor();
return new QualifierResolveResult(containingClass, substitutor, true);
}
}
} else {
final PsiTypeElement typeElement = methodReferenceExpression.getQualifierType();
if (typeElement != null) {
PsiType type = getExpandedType(typeElement.getType(), typeElement);
PsiClassType.ClassResolveResult result = PsiUtil.resolveGenericsClassInType(type);
containingClass = result.getElement();
if (containingClass != null) {
return new QualifierResolveResult(containingClass, result.getSubstitutor(), true);
}
}
}
return new QualifierResolveResult(containingClass, substitutor, false);
}
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;
}
public static boolean hasReceiver(
@NotNull PsiMethodReferenceExpression methodRef, @NotNull PsiMethod method) {
return hasReceiver(methodRef, method, methodRef.getFunctionalInterfaceType());
}
public static String checkMethodReferenceContext(
PsiMethodReferenceExpression methodRef, PsiElement resolve, PsiType functionalInterfaceType) {
final PsiClass containingClass =
resolve instanceof PsiMethod
? ((PsiMethod) resolve).getContainingClass()
: (PsiClass) resolve;
final boolean isStaticSelector = isStaticallyReferenced(methodRef);
final PsiElement qualifier = methodRef.getQualifier();
boolean isMethodStatic = false;
boolean receiverReferenced = false;
boolean isConstructor = true;
if (resolve instanceof PsiMethod) {
final PsiMethod method = (PsiMethod) resolve;
isMethodStatic = method.hasModifierProperty(PsiModifier.STATIC);
isConstructor = method.isConstructor();
receiverReferenced = hasReceiver(methodRef, method, functionalInterfaceType);
if (method.hasModifierProperty(PsiModifier.ABSTRACT)
&& qualifier instanceof PsiSuperExpression) {
return "Abstract method '" + method.getName() + "' cannot be accessed directly";
}
}
if (!receiverReferenced && isStaticSelector && !isMethodStatic && !isConstructor) {
return "Non-static method cannot be referenced from a static context";
}
if (!receiverReferenced && !isStaticSelector && isMethodStatic) {
return "Static method referenced through non-static qualifier";
}
if (receiverReferenced && isStaticSelector && isMethodStatic && !isConstructor) {
return "Static method referenced through receiver";
}
if (isMethodStatic && isStaticSelector && qualifier instanceof PsiTypeElement) {
final PsiJavaCodeReferenceElement referenceElement =
PsiTreeUtil.getChildOfType(qualifier, PsiJavaCodeReferenceElement.class);
if (referenceElement != null) {
final PsiReferenceParameterList parameterList = referenceElement.getParameterList();
if (parameterList != null && parameterList.getTypeArguments().length > 0) {
return "Parameterized qualifier on static method reference";
}
}
}
if (isConstructor) {
if (containingClass != null
&& PsiUtil.isInnerClass(containingClass)
&& containingClass.isPhysical()) {
PsiClass outerClass = containingClass.getContainingClass();
if (outerClass != null
&& !InheritanceUtil.hasEnclosingInstanceInScope(outerClass, methodRef, true, false)) {
return "An enclosing instance of type "
+ PsiFormatUtil.formatClass(outerClass, PsiFormatUtilBase.SHOW_NAME)
+ " is not in scope";
}
}
}
return null;
}
public static String checkMethodReferenceContext(PsiMethodReferenceExpression methodRef) {
final PsiElement resolve = methodRef.resolve();
if (resolve == null) return null;
return checkMethodReferenceContext(methodRef, resolve, methodRef.getFunctionalInterfaceType());
}