Game doesn't end when checkmated in Warped Coast

[QuickBanjo]

HyperRogue version: 13.0a
Operating system: Android 16

Setup:

1. Start a new game of HyperRogue classic.
2. Find a Warped Coast.
3. Become unable to move without getting killed.

Expected behavior:

When the player becomes unable to move, they are checkmated, and the game ends.

Actual behvaior:

The player cannot move, but the game does not end. See attached example. In this example, the boat is adjacent to the player's hex and out of range of the Ratling. The player cannot move onto the boat due to Warped Coast rules, as intended, yet the game does not recognize this as checkmate.

In checkmove.cpp, I did not see any obvious checks for this edge case, and I suspect this may occur even without a boat or water.

Click to view screenshot

[josephcsible]

You're not checkmated there, because even though you can't move, you can still pass your turn without dying. After doing that enough times, wandering monsters or ghosts will spawn, which will let you escape if you're lucky, or will actually checkmate you if you're unlucky.

[QuickBanjo]

Ah, I forgot about the wandering ghosts. The HyperRogue Wiki even mentions this specific situation.

But would this still work if all cells at distance 2 have Ratlings in them? The wiki says ghosts can go through walls and tentacles, but it doesn't say whether they can go through normal monsters such as Ratling. If not, does that warrant opening a separate issue?

[josephcsible]

That indeed causes a true softlock. And a solution like tortoises have isn't even good enough, because there might be a wall of ratlings 2 thick, and then the ghosts could only scare the outer ring, which couldn't move even if they wanted to. Maybe the solution to that could be that ghosts can switch places with ratlings.