diff --git a/src/testdir/test_let.vim b/src/testdir/test_let.vim
index 017b2a4..6dc36ea 100644
--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -250,23 +250,23 @@
     let &t_k1 = old_t_k1
   endif
 
-  call assert_fails('let x = &t_xx', 'E113')
+  call assert_fails('let x = &t_xx', 'E113:')
   let &t_xx = "yes"
   call assert_equal("yes", &t_xx)
   let &t_xx = ""
-  call assert_fails('let x = &t_xx', 'E113')
+  call assert_fails('let x = &t_xx', 'E113:')
 endfunc
 
 func Test_let_option_error()
   let _w = &tw
   let &tw = 80
-  call assert_fails('let &tw .= 1', 'E734')
+  call assert_fails('let &tw .= 1', 'E734:')
   call assert_equal(80, &tw)
   let &tw = _w
 
   let _w = &fillchars
   let &fillchars = "vert:|"
-  call assert_fails('let &fillchars += "diff:-"', 'E734')
+  call assert_fails('let &fillchars += "diff:-"', 'E734:')
   call assert_equal("vert:|", &fillchars)
   let &fillchars = _w
 endfunc