Reported directly to devteam by entrez via email:
>
> I noticed some potential issues with (melting) ice:
>
> * Digging down into ice, or setting a land mine on the ice and
> triggering it, doesn't remove the melt_ice timeout, so it can result
> in a sequence like dig down -> pit fills with water -> freeze water
> -> freezing water tries to set melt_ice timeout -> duplicate timeout
> impossible. Or if you don't freeze the water again, melt_ice will
> run on a non-ice surface, which might at least produce strange
> messages.
>
> * Setting a land mine on ice: melting ice doesn't do anything with
> the trap, so there is still a land mine which you can trigger by
> flying over the water (the land mine's trigger is also still
> described as being 'in a pile of soil', despite being underwater at
> this point). Similar thing happens with bear traps.
>
> * Not really related to _melting_ ice, but an exploding land mine
> doesn't reset the typ from ICE to FLOOR (like normal digging does),
> so it will result in a square with a pit that is also an ice square,
> where the ice can melt under the pit and produce a combination
> pit/moat. If you then freeze the moat, the pit reappears on top of
> the ice.
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