diff --git a/src/evalfunc.c b/src/evalfunc.c
index 1764f41..aefb1bf 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2936,7 +2936,7 @@
     // using Lists and Dicts internally.  E.g.: ":echo [garbagecollect()]".
     want_garbage_collect = TRUE;
 
-    if (argvars[0].v_type != VAR_UNKNOWN && tv_get_number(&argvars[0]) == 1)
+    if (argvars[0].v_type != VAR_UNKNOWN && tv_get_bool(&argvars[0]) == 1)
 	garbage_collect_at_exit = TRUE;
 }