this might fix the landfill stuff

Author: protocol-1903

migrations/PyBlock_3.2.0.lua

@@ -1,21 +1,39 @@
 local surfaces = game.surfaces
 
 for _, surface in pairs(game.surfaces) do
+  -- get non-landfill non-water tiles that do have a hidden tile but not double hidden (i.e. stone bricks on landfill not on water)
+  local double_tiles = surface.find_tiles_filtered{
+    collision_mask = "water_tile",
+    name = "landfill",
+    has_hidden_tile = false,
+    has_double_hidden_tile = true,
+    invert = true
+  }
+
+  -- set water as the double hidden tile for those tiles
+  for _, tile in pairs(double_tiles) do
+    surface.set_double_hidden_tile(tile.position, "water")
+  end
+
+  -- find landfill tiles that do not have a hidden tile (i.e. landfill as the base tile, not minable)
   local landfill = surface.find_tiles_filtered{
     name = "landfill",
     has_hidden_tile = false
   }
+
   -- set water as hidden tile
   for _, tile in pairs(landfill) do
     surface.set_hidden_tile(tile.position, "water")
   end
 
-  -- get normal non-water tiles
+  -- get non-landfill non-water tiles that do not have a hidden tile and not double hidden (i.e. mapgen placed dirt or sand)
   local tiles = surface.find_tiles_filtered{
     collision_mask = "water_tile",
     name = "landfill",
+    has_hidden_tile = true,
     invert = true
   }
+
   local to_replace = {}
   for _, tile in pairs(tiles) do
     to_replace[#to_replace+1] = {
@@ -29,8 +47,8 @@ for _, surface in pairs(game.surfaces) do
     to_replace
   )
 
-  -- set water as hidden tile
+  -- set water as hidden tile (order required because reasons)
   for _, tile in pairs(to_replace) do
     surface.set_hidden_tile(tile.position, "water")
   end
-end
+end