Xtend does not accept annotation @Nullable on parameter

[frankbenoit]

Using org.eclipse.jdt.annotations.

Is there a problem if the annotation has

@Target({ TYPE_USE })

like @Nullable/@nonnull have it?

def String func( @Nullable String s ){ ...

results in: The annotation @nullable is disallowed at this location

[cdietrich]

see also #2360

[LorenzoBettini]

If I understand it correctly, the "culprit" is in XtendValidator here:

	@Check
	public void checkAnnotationTarget(XAnnotation annotation) {
		JvmType annotationType = annotation.getAnnotationType();
		if (annotationType == null || annotationType.eIsProxy() || !(annotationType instanceof JvmAnnotationType)) {
			return;
		}
		Set<ElementType> targets = annotationUtil.getAnnotationTargets((JvmAnnotationType) annotationType);
		if (targets.isEmpty())
			return;
		final EObject eContainer = getContainingAnnotationTarget(annotation);
		Class<? extends EObject> clazz = eContainer.getClass();
		if (eContainer instanceof XtendField && eContainer.eContainer() instanceof XtendAnnotationType) {
			clazz = XtendFunction.class;
		}
		for (Entry<Class<?>, Collection<ElementType>> mapping : targetInfos.asMap().entrySet()) {
			if (mapping.getKey().isAssignableFrom(clazz)) {
				targets.retainAll(mapping.getValue());
				if (targets.isEmpty()) {
					error("The annotation @" + annotation.getAnnotationType().getSimpleName()
							+ " is disallowed for this location.", annotation, null, INSIGNIFICANT_INDEX,
							ANNOTATION_WRONG_TARGET);
				}
			}
		}
	}

it should be enough to update this initialization accordingly:

	protected final Multimap<Class<?>, ElementType> targetInfos;
	
	{
		ImmutableMultimap.Builder<Class<?>, ElementType> result = ImmutableMultimap.builder();
		result.put(XtendClass.class, ElementType.TYPE);
		result.put(XtendInterface.class, ElementType.TYPE);
		result.put(XtendEnum.class, ElementType.TYPE);
		result.putAll(XtendAnnotationType.class, ElementType.ANNOTATION_TYPE, ElementType.TYPE);
		result.put(XtendField.class, ElementType.FIELD);
		result.put(XtendFunction.class, ElementType.METHOD);
		result.put(XtendParameter.class, ElementType.PARAMETER);
		targetInfos = result.build();
	}

Do I underestimate anything? cc @szarnekow

[cdietrich]

maybe:
#2360 (comment)

[LorenzoBettini]

@cdietrich but that is a syntactic issue for fields. I was focusing on this issue, which is about parameter types.

[cdietrich]

@X @Y Type name

[cdietrich]

Do x and y go to the type or the field
What are you targeting

[LorenzoBettini]

But this issue is about parameters

[cdietrich]

So you would allow it just at this place ?

[LorenzoBettini]

Just as a first step; I had the feeling that for this issue you don't need to change the grammar but only the validator. For parameters, the grammar already allows the annotation to be placed there, but the validator only allows for ElementType.PARAMETER.