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;
 }
 
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 8651ef8..7cc323c 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -1285,6 +1285,10 @@
   assert_equal(6, res)
 enddef
 
+def Test_garbagecollect()
+  garbagecollect(true)
+enddef
+
 def Test_insert_return_type()
   let l = insert([2, 1], 3)
   let res = 0
diff --git a/src/version.c b/src/version.c
index 8ebf9a7..ab9c0c4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1601,
+/**/
     1600,
 /**/
     1599,