@Nullable
public static PsiType getExpectedClosureReturnType(GrClosableBlock closure) {
final Set<PsiType> expectedTypes = getDefaultExpectedTypes(closure);
List<PsiType> expectedReturnTypes = new ArrayList<PsiType>();
for (PsiType expectedType : expectedTypes) {
if (!(expectedType instanceof PsiClassType)) return null;
final PsiClassType.ClassResolveResult resolveResult =
((PsiClassType) expectedType).resolveGenerics();
final PsiClass resolved = resolveResult.getElement();
if (resolved == null
|| !(GroovyCommonClassNames.GROOVY_LANG_CLOSURE.equals(resolved.getQualifiedName())))
return null;
final PsiTypeParameter[] typeParameters = resolved.getTypeParameters();
if (typeParameters.length != 1) return null;
final PsiTypeParameter expected = typeParameters[0];
final PsiType expectedReturnType = resolveResult.getSubstitutor().substitute(expected);
if (expectedReturnType == PsiType.VOID || expectedReturnType == null) return null;
expectedReturnTypes.add(expectedReturnType);
}
return TypesUtil.getLeastUpperBoundNullable(expectedReturnTypes, closure.getManager());
}
@Nullable
private static Boolean isAssignableForNativeTypes(
@NotNull PsiType lType, @NotNull PsiClassType rType, @NotNull PsiElement context) {
if (!(lType instanceof PsiClassType)) return null;
final PsiClassType.ClassResolveResult leftResult = ((PsiClassType) lType).resolveGenerics();
final PsiClassType.ClassResolveResult rightResult = rType.resolveGenerics();
final PsiClass leftClass = leftResult.getElement();
PsiClass rightClass = rightResult.getElement();
if (rightClass == null || leftClass == null) return null;
if (!InheritanceUtil.isInheritorOrSelf(rightClass, leftClass, true)) return Boolean.FALSE;
PsiSubstitutor rightSubstitutor = rightResult.getSubstitutor();
if (!leftClass.hasTypeParameters()) return Boolean.TRUE;
PsiSubstitutor leftSubstitutor = leftResult.getSubstitutor();
if (!leftClass.getManager().areElementsEquivalent(leftClass, rightClass)) {
rightSubstitutor =
TypeConversionUtil.getSuperClassSubstitutor(leftClass, rightClass, rightSubstitutor);
rightClass = leftClass;
} else if (!rightClass.hasTypeParameters()) return Boolean.TRUE;
Iterator<PsiTypeParameter> li = PsiUtil.typeParametersIterator(leftClass);
Iterator<PsiTypeParameter> ri = PsiUtil.typeParametersIterator(rightClass);
while (li.hasNext()) {
if (!ri.hasNext()) return Boolean.FALSE;
PsiTypeParameter lp = li.next();
PsiTypeParameter rp = ri.next();
final PsiType typeLeft = leftSubstitutor.substitute(lp);
if (typeLeft == null) continue;
final PsiType typeRight = rightSubstitutor.substituteWithBoundsPromotion(rp);
if (typeRight == null) {
return Boolean.TRUE;
}
if (!isAssignableWithoutConversions(typeLeft, typeRight, context)) return Boolean.FALSE;
}
return Boolean.TRUE;
}
