Given an object, how to call an alias to a member function on it?

[Quirin Schroll via Digitalmars-d-learn]

How do I invoke the member function in a reliable way? Given 
`obj` of the type of the object, I used `mixin("obj.", 
__traits(identifier, memberFunc), "(params)")`, but that has 
issues, among probably others, definitely with visibility. (The 
member function alias is a template parameter.)