Create specially-solved DataToTag class
See #20532 (closed). (And also see ghc-proposals#530 for my interest in that issue.)
See this Core Libraries Commitee issue on the API design for this MR
TODO:
-
internal documentation (Note in GHC.Tc.Instance.Class
, etc.) -
external documentation (changelog entry, etc.) -
code clean-up -
test cases -
Add "small" dataToTag primop? (left as future work) -
hide the underlying primop(s) (hidden from base
only) -
figure out what to do for properly lev-poly data declarations
Edited by Matthew Craven