I need to get Tree for TypeParameterElement that is not part of the file where I
change the source. When I call SourceUtils.treeFor I get null.

I have something like 

class TestClass<T> {
}

where T is the TypeParameterElement I hold.

It seems there is an invalid Scope since even if I run a user action task on the
TestClass.java CompilationInfo.getTrees().getScope(path).getEnclosingClass(),
where path is TreePath to T parameter, returns null too.