GHC 8.6 support about list-tries HOT 2 CLOSED

Apparently there's also a compile error when building against the latest containers:

Data/ListTrie/Base/Map.hs:346:17: error:
    • Data.Map.insertWith' is gone. Use Data.Map.Strict.insertWith.
    • In the expression: M.insertWith'
      In an equation for ‘insertWith’: insertWith = M.insertWith'
      In the instance declaration for ‘Map M.Map k’

from list-tries.

Yes, I'm afraid it's not as simple as bumping upper bounds. containers 0.6 removes the old semi-strict insertWith'-style APIs from Data.Map which have been deprecated for a long time. In principle we could remove the one character and use plain insertWith, but I'm unsure as to what kind of behavioural effect that has so I'm a bit uncomfortable with doing it just off the cuff.

My understanding is that these APIs were removed in favour of Data.Map.Strict because they were misleading and not as strict as people expected, but that they did still behave differently than the fully lazy versions. Perhaps the correct thing to do for list-tries would be to use Data.Map.Strict internally, but that's another thing that would need a bit deeper evaluation.

Unfortunately my time is really limited these days and list-tries has suffered for it. Since I'm unlikely to be able to take the time to do a proper analysis any time soon, I'm going to have to go with the "PRs welcome" response here. Note that fixing the compile error is easy — the key issue is that I'd like to have some understanding of the implications.

from list-tries.