diff --git a/src/eval.c b/src/eval.c
index a45b71d..7d28e71 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -19195,11 +19195,21 @@
 		    goto theend;	/* type error; errmsg already given */
 		if (i == 1)
 		    info.item_compare_ic = TRUE;
-		else
+		else if (argvars[1].v_type != VAR_NUMBER)
 		    info.item_compare_func = get_tv_string(&argvars[1]);
+		else if (i != 0)
+		{
+		    EMSG(_(e_invarg));
+		    goto theend;
+		}
 		if (info.item_compare_func != NULL)
 		{
-		    if (STRCMP(info.item_compare_func, "n") == 0)
+		    if (*info.item_compare_func == NUL)
+		    {
+			/* empty string means default sort */
+			info.item_compare_func = NULL;
+		    }
+		    else if (STRCMP(info.item_compare_func, "n") == 0)
 		    {
 			info.item_compare_func = NULL;
 			info.item_compare_numeric = TRUE;
diff --git a/src/testdir/test_sort.vim b/src/testdir/test_sort.vim
index 2b097ce..819514a 100644
--- a/src/testdir/test_sort.vim
+++ b/src/testdir/test_sort.vim
@@ -35,3 +35,11 @@
   " test ability to call sort() from a compare function
   call assert_equal([1, 3, 5], sort([3, 1, 5], 'Compare1'))
 endfunc
+
+func Test_sort_default()
+  " docs say omitted, empty or zero argument sorts on string representation.
+  call assert_equal(["2", 1, 3.3], sort([3.3, 1, "2"]))
+  call assert_equal(["2", 1, 3.3], sort([3.3, 1, "2"], ''))
+  call assert_equal(["2", 1, 3.3], sort([3.3, 1, "2"], 0))
+  call assert_fails('call sort([3.3, 1, "2"], 3)', "E474")
+endfunc
diff --git a/src/version.c b/src/version.c
index f4ffb8f..24a27cc 100644
--- a/src/version.c
+++ b/src/version.c
@@ -744,6 +744,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1464,
+/**/
     1463,
 /**/
     1462,