-- The main loop may do unification, and that may crash if
-- it doesn't see a TcTyVar, so we have to instantiate. Sigh
-- ToDo: what if two of them do get unified?
- newDicts DerivOrigin (substTheta tenv theta) `thenM` \ wanteds ->
+ newDictBndrsO orig (substTheta tenv theta) `thenM` \ wanteds ->
simpleReduceLoop doc reduceMe wanteds `thenM` \ (frees, _, irreds) ->
ASSERT( null frees ) -- reduceMe never returns Free