[#149] allow extension fields in java 8 interfaces

[cdietrich]

[#149] allow extension fields in java 8 interfaces

[szarnekow]

I assume the extensions are available in classes implementing the interface, too

[szarnekow]

Nice

[cdietrich]

I assume the extensions are available in classes implementing the interface, too

didnt test this. do we look up extensions in superclasses? i assume no otherwise api eg in generated inferrer would be easier?

[szarnekow]

I think we consider inherited extensions. It should just work

[cdietrich]

it does not. there is this done?

[szarnekow]

it does not. there is this done?

Hmm for classes I see the equivalent example working fine:

class A {
	public static extension String s;
	def void m1(int i) {
		i.substring();
	}
}
class B extends A {
	def void m2(int i) {
		i.substring();
	}
}

[szarnekow]

And indeed it fails for interfaces:

interface A {
	@Extension
	public static String s;
	def void m1(int i) {
		i.substring();
	}
}
class B implements A {
	def void m2(int i) {
		i.substring(); // error
	}
}

[szarnekow]

org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.addExtensionFieldsToMemberSession(ResolvedTypes, IFeatureScopeSession, JvmDeclaredType, JvmIdentifiableElement, Set<String>, Set<JvmType>) is only traversing the extended class with the wrong assumption that interfaces don't define fields.

[cdietrich]

replaced with eclipse-xtext/xtext#2591