diff --git a/src/eval.c b/src/eval.c
index fd028cc..7776cc6 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -9386,7 +9386,8 @@
 	char_u	buf[NUMBUFLEN];
 	char	*error = (char *)get_tv_string_buf_chk(&argvars[1], buf);
 
-	if (strstr((char *)vimvars[VV_ERRMSG].vv_str, error) == NULL)
+	if (error == NULL
+		  || strstr((char *)vimvars[VV_ERRMSG].vv_str, error) == NULL)
 	{
 	    prepare_assert_error(&ga);
 	    fill_assert_error(&ga, &argvars[2], NULL, &argvars[1],
diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index df2636d..2ac828b 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -62,6 +62,12 @@
   endtry
 endfunc
 
+func Test_assert_fail_fails()
+  call assert_fails('xxx', {})
+  call assert_true(v:errors[0] =~ "Expected {} but got 'E731:")
+  call remove(v:errors, 0)
+endfunc
+
 
 func Test_user_is_happy()
   smile
diff --git a/src/version.c b/src/version.c
index e4004f8..eecbfe1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -744,6 +744,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1567,
+/**/
     1566,
 /**/
     1565,