invocation
A map from each reachable looked-up A_Function to a Pair containing an L2BasicBlock in which code generation for invocation of this function should/did take place, and a lambda which will cause that code generation to happen.
This construct theoretically deals with method lookups that lead to the same function multiple ways (it's unclear if the lookup tree mechanism will ever evolve to produce this situation), but more practically, it can de-duplicate a successful inlined lookup and the success path of the fall-back slow lookup when it knows there is only one particular definition that a successful slow lookup could produce.