diff --git a/src/evalfunc.c b/src/evalfunc.c
index 060b5bb..029c8a6 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -5961,7 +5961,10 @@
     if (end != NULL && lv.ll_name != NULL)
     {
 	if (*end != NUL)
-	    semsg(_(e_trailing_arg), end);
+	{
+	    semsg(_(lv.ll_name == lv.ll_name_end
+					   ? e_invarg2 : e_trailing_arg), end);
+	}
 	else
 	{
 	    if (lv.ll_tv == NULL)
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index a4ca5d4..e0b0314 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -95,6 +95,11 @@
   call assert_fails('let x = copy([test_void()])', 'E1031:')
 endfunc
 
+func Test_islocked()
+  call assert_fails('call islocked(99)', 'E475:')
+  call assert_fails('call islocked("s: x")', 'E488:')
+endfunc
+
 func Test_len()
   call assert_equal(1, len(0))
   call assert_equal(2, len(12))
diff --git a/src/version.c b/src/version.c
index ace5a9d..3de3048 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3158,
+/**/
     3157,
 /**/
     3156,