RecordCon lookup: don't fallback to the type level
This MR adds extra logic when looking up a record constructor. If GHC.Rename.Env.lookupOccRnConstr returns a TyCon (as it may, due to the logic explained in Note [Pattern to type (P2T) conversion]), we emit an error saying that the data constructor is not in scope.
This avoids the compiler falling over shortly thereafter, in the call to 'lookupConstructorInfo' inside 'GHC.Rename.Env.lookupRecFieldOcc', because the record constructor would not have been a ConLike.
Edited by sheaf