private static boolean isInExtendsList(
final RefJavaElement to, final PsiReferenceList extendsList) {
if (extendsList != null) {
final PsiJavaCodeReferenceElement[] referenceElements = extendsList.getReferenceElements();
for (PsiJavaCodeReferenceElement referenceElement : referenceElements) {
final PsiReferenceParameterList parameterList = referenceElement.getParameterList();
if (parameterList != null) {
for (PsiType type : parameterList.getTypeArguments()) {
if (extendsList
.getManager()
.areElementsEquivalent(PsiUtil.resolveClassInType(type), to.getElement())) {
return true;
}
}
}
}
}
return false;
}
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;
}
