[adonovan]

It is a consequence of (a) Go's implicit relationship between a concrete type and the interfaces it implements and (b) Go's "heterogenous" translation of generics (like C++, unlike Java). Together, this means you can't know which methods you need a priori. All proposed solutions to date essentially compromise on (a) by limiting the generic "implements" relation to things known at build time, or on (b) by making generic methods "homegenous" (aka boxed) and thus slow (see https://github.com/golang/go/issues/49085#issuecomment-23163... for an elaboration of this approach); or, they involve dynamic code generation.