public static boolean isLambdaFullyInferred(
PsiLambdaExpression expression, PsiType functionalInterfaceType) {
final boolean hasParams = expression.getParameterList().getParametersCount() > 0;
if (hasParams
|| getFunctionalInterfaceReturnType(functionalInterfaceType)
!= PsiType.VOID) { // todo check that void lambdas without params check
return !dependsOnTypeParams(functionalInterfaceType, functionalInterfaceType, expression);
}
return true;
}
public static boolean isFreeFromTypeInferenceArgs(
final PsiParameter[] methodParameters,
final PsiLambdaExpression lambdaExpression,
final PsiExpression expression,
final PsiSubstitutor subst,
final PsiType functionalInterfaceType,
final PsiTypeParameter typeParam) {
if (expression instanceof PsiCallExpression
&& ((PsiCallExpression) expression).getTypeArguments().length > 0) return true;
if (expression instanceof PsiNewExpression) {
final PsiJavaCodeReferenceElement classReference =
((PsiNewExpression) expression).getClassOrAnonymousClassReference();
if (classReference != null) {
final PsiReferenceParameterList parameterList = classReference.getParameterList();
if (parameterList != null) {
final PsiTypeElement[] typeParameterElements = parameterList.getTypeParameterElements();
if (typeParameterElements.length > 0) {
if (!(typeParameterElements[0].getType() instanceof PsiDiamondType)) {
return true;
}
}
}
}
}
final PsiParameter[] lambdaParams = lambdaExpression.getParameterList().getParameters();
if (lambdaParams.length != methodParameters.length) return false;
final boolean[] independent = {true};
final PsiMethod interfaceMethod = getFunctionalInterfaceMethod(functionalInterfaceType);
if (interfaceMethod == null) return false;
final TypeParamsChecker paramsChecker = new TypeParamsChecker(lambdaExpression);
for (PsiParameter parameter : interfaceMethod.getParameterList().getParameters()) {
subst.substitute(parameter.getType()).accept(paramsChecker);
}
paramsChecker.myUsedTypeParams.add(typeParam);
expression.accept(
new JavaRecursiveElementWalkingVisitor() {
@Override
public void visitConditionalExpression(PsiConditionalExpression expression) {
final PsiExpression thenExpression = expression.getThenExpression();
if (thenExpression != null) {
thenExpression.accept(this);
}
final PsiExpression elseExpression = expression.getElseExpression();
if (elseExpression != null) {
elseExpression.accept(this);
}
}
@Override
public void visitReferenceExpression(PsiReferenceExpression expression) {
super.visitReferenceExpression(expression);
int usedParamIdx = -1;
for (int i = 0; i < lambdaParams.length; i++) {
PsiParameter param = lambdaParams[i];
if (expression.isReferenceTo(param)) {
usedParamIdx = i;
break;
}
}
if (usedParamIdx > -1
&& dependsOnTypeParams(
subst.substitute(methodParameters[usedParamIdx].getType()),
functionalInterfaceType,
lambdaExpression,
paramsChecker.myUsedTypeParams.toArray(
new PsiTypeParameter[paramsChecker.myUsedTypeParams.size()]))) {
independent[0] = false;
}
}
});
return independent[0];
}
public static boolean isAcceptable(
PsiLambdaExpression lambdaExpression, final PsiType leftType, boolean checkReturnType) {
if (leftType instanceof PsiIntersectionType) {
for (PsiType conjunctType : ((PsiIntersectionType) leftType).getConjuncts()) {
if (isAcceptable(lambdaExpression, conjunctType, checkReturnType)) return true;
}
return false;
}
final PsiClassType.ClassResolveResult resolveResult =
PsiUtil.resolveGenericsClassInType(GenericsUtil.eliminateWildcards(leftType));
final PsiClass psiClass = resolveResult.getElement();
if (psiClass instanceof PsiAnonymousClass) {
return isAcceptable(
lambdaExpression, ((PsiAnonymousClass) psiClass).getBaseClassType(), checkReturnType);
}
final MethodSignature methodSignature = getFunction(psiClass);
if (methodSignature == null) return false;
final PsiParameter[] lambdaParameters = lambdaExpression.getParameterList().getParameters();
final PsiType[] parameterTypes = methodSignature.getParameterTypes();
if (lambdaParameters.length != parameterTypes.length) return false;
for (int lambdaParamIdx = 0, length = lambdaParameters.length;
lambdaParamIdx < length;
lambdaParamIdx++) {
PsiParameter parameter = lambdaParameters[lambdaParamIdx];
final PsiTypeElement typeElement = parameter.getTypeElement();
if (typeElement != null) {
final PsiType lambdaFormalType = typeElement.getType();
final PsiType methodParameterType = parameterTypes[lambdaParamIdx];
if (lambdaFormalType instanceof PsiPrimitiveType) {
if (methodParameterType instanceof PsiPrimitiveType)
return methodParameterType.equals(lambdaFormalType);
return false;
}
if (!TypeConversionUtil.erasure(lambdaFormalType)
.isAssignableFrom(
TypeConversionUtil.erasure(
GenericsUtil.eliminateWildcards(
resolveResult
.getSubstitutor()
.substitute(
methodSignature
.getSubstitutor()
.substitute(methodParameterType)))))) {
return false;
}
}
}
if (checkReturnType) {
final String uniqueVarName =
JavaCodeStyleManager.getInstance(lambdaExpression.getProject())
.suggestUniqueVariableName("l", lambdaExpression, true);
String canonicalText = leftType.getCanonicalText();
if (leftType instanceof PsiEllipsisType) {
canonicalText = ((PsiEllipsisType) leftType).toArrayType().getCanonicalText();
}
final PsiStatement assignmentFromText =
JavaPsiFacade.getElementFactory(lambdaExpression.getProject())
.createStatementFromText(
canonicalText + " " + uniqueVarName + " = " + lambdaExpression.getText(),
lambdaExpression);
final PsiLocalVariable localVariable =
(PsiLocalVariable)
((PsiDeclarationStatement) assignmentFromText).getDeclaredElements()[0];
LOG.assertTrue(psiClass != null);
PsiType methodReturnType = getReturnType(psiClass, methodSignature);
if (methodReturnType != null) {
methodReturnType =
resolveResult
.getSubstitutor()
.substitute(methodSignature.getSubstitutor().substitute(methodReturnType));
return LambdaHighlightingUtil.checkReturnTypeCompatible(
(PsiLambdaExpression) localVariable.getInitializer(), methodReturnType)
== null;
}
}
return true;
}