diff --git a/src/nhlsel.c b/src/nhlsel.c
index fba73357c..b65f3216d 100644
--- a/src/nhlsel.c
+++ b/src/nhlsel.c
@@ -91,7 +91,7 @@ lua_State *L;
 {
     struct selectionvar *tmp = selection_new();
     struct selectionvar
-        *sel = (struct selectionvar *) lua_newuserdata(L, sizeof sel);
+        *sel = (struct selectionvar *) lua_newuserdata(L, sizeof(struct selectionvar));
 
     luaL_getmetatable(L, "selection");
     lua_setmetatable(L, -2);
diff --git a/src/sp_lev.c b/src/sp_lev.c
index dc2df6a77..3eb228453 100644
--- a/src/sp_lev.c
+++ b/src/sp_lev.c
@@ -3581,7 +3581,7 @@ lua_State *L UNUSED;
 struct selectionvar *
 selection_new()
 {
-    struct selectionvar *tmps = (struct selectionvar *) alloc(sizeof tmps);
+    struct selectionvar *tmps = (struct selectionvar *) alloc(sizeof(struct selectionvar));
 
     tmps->wid = COLNO;
     tmps->hei = ROWNO;