diff --git a/src/shadowcasting.cpp b/src/shadowcasting.cpp
index 64247ef8a5e01..af2859fdb0cfd 100644
--- a/src/shadowcasting.cpp
+++ b/src/shadowcasting.cpp
@@ -63,18 +63,6 @@ struct span {
     bool skip_first_row;
 };
 
-// Add defaults for when method is invoked for the first time.
-template<int xx, int xy, int xz, int yx, int yy, int yz, int zz, typename T,
-         T( *calc )( const T &, const T &, const int & ),
-         bool( *check )( const T &, const T & ),
-         T( *accumulate )( const T &, const T &, const int & )>
-void cast_zlight_segment(
-    const std::array<T( * )[MAPSIZE_X][MAPSIZE_Y], OVERMAP_LAYERS> &output_caches,
-    const std::array<const T( * )[MAPSIZE_X][MAPSIZE_Y], OVERMAP_LAYERS> &input_arrays,
-    const std::array<const bool ( * )[MAPSIZE_X][MAPSIZE_Y], OVERMAP_LAYERS> &floor_caches,
-    const tripoint &offset, const int offset_distance,
-    const T numerator = 1.0f );
-
 template<int xx, int xy, int xz, int yx, int yy, int yz, int zz, typename T,
          T( *calc )( const T &, const T &, const int & ),
          bool( *check )( const T &, const T & ),