+ -- <<<
+ -- These two productions deliberately have a shift-reduce conflict. I have made 'group' into a special_id,
+ -- which means you can enable TransformListComp while still using Data.List.group. However, this makes the two
+ -- productions ambiguous. I've set things up so that Happy chooses to resolve the conflict in that case by
+ -- choosing the "group by" variant, which is what we want.
+ --
+ -- This is rather dubious: the user might be confused as to how to parse this statement. However, it is a good
+ -- practical choice. NB: Data.List.group :: [a] -> [[a]], so using the first production would not even type check
+ -- if /that/ is the group function we conflict with.