Interleaving of multiple passes

[spacekitteh]

There should be a combinator to take an arbitrary list of passes, and interleave them into a single pass where the fact type is a type-level list of other fact types:

interleavePasses :: [forall f. FwdPass m n f] -> FwdPass m n '[]

This seems quite Effective (pun most certainly intended).

[mlite]

Is this really possible without understanding what each pass is doing? It seems it requires each pass be both commutative and associative.