I am working the next stage of Trees that Grow into GHC [1], and need to update Haddock.

The `Specialize` module[2] exports a single function, `specializeInstHead` which is called once, specialised to `GhcRn`.

So all it needs to be for haddock use is

specializeInstHead :: InstHead GhcRn -> InstHead GhcRn

But the entire module is polymorphic in the AST parameter, so it has the following instead

specializeInstHead :: (Ord (IdP name), DataId name, SetName (IdP name),

NamedThing (IdP name))

=> InstHead name -> InstHead name

Question: does it need to be so polymorphic?

I am hitting issues getting the type parameter change worked through, and it seems a bit pointless to slog on with it if it is unnecessary.

Alan