diff --git a/grid.cabal b/grid.cabal
--- a/grid.cabal
+++ b/grid.cabal
@@ -1,5 +1,5 @@
 Name:              grid
-Version:           7.7.1
+Version:           7.8.0
 Stability:         experimental
 Synopsis:          Tools for working with regular grids (graphs, lattices).
 Description:       Provides tools for working with regular arrangements
@@ -27,7 +27,7 @@
 source-repository this
   type:     git
   location: https://github.com/mhwombat/grid.git
-  tag:      7.7.1
+  tag:      7.8.0
 
 
 library
diff --git a/src/Math/Geometry/GridInternal.hs b/src/Math/Geometry/GridInternal.hs
--- a/src/Math/Geometry/GridInternal.hs
+++ b/src/Math/Geometry/GridInternal.hs
@@ -190,7 +190,7 @@
 -- | A regular arrangement of tiles where the number of tiles is finite.
 --   Minimal complete definition: @'size'@, @'maxPossibleDistance'@.
 class Grid g => FiniteGrid g where
-  type Size s
+  type Size g
   -- | Returns the dimensions of the grid.
   --   For example, if @g@ is a 4x3 rectangular grid, @'size' g@ would
   --   return @(4, 3)@, while @'tileCount' g@ would return @12@.
diff --git a/src/Math/Geometry/GridMap.hs b/src/Math/Geometry/GridMap.hs
--- a/src/Math/Geometry/GridMap.hs
+++ b/src/Math/Geometry/GridMap.hs
@@ -30,9 +30,7 @@
   ) where
 
 import Prelude hiding (lookup, map, foldr, foldl, foldr1, foldl1, null)
-import Data.Foldable (Foldable)
 import qualified Data.Map as M
---import qualified Data.Map.Strict as Strict (Map)
 import qualified Math.Geometry.Grid as G
 
 -- | A regular arrangement of tiles, having a value associated with