diff --git a/src/p_slopes.c b/src/p_slopes.c
index 48a13a07d61bc88b45a67ce4d5a0e181b31b53f6..9648a3c456f2600f414333b9aca7e5be79386272 100644
--- a/src/p_slopes.c
+++ b/src/p_slopes.c
@@ -328,7 +328,7 @@ static void line_SpawnViaLine(const int linenum, const boolean spawnthinker)
 
 	if(!frontfloor && !backfloor && !frontceil && !backceil)
 	{
-		CONS_Printf("line_SpawnViaLine: Slope special with nothing to do.\n");
+		CONS_Printf("line_SpawnViaLine: Slope special with nothing to do.\n", linenum);
 		return;
 	}