diff --git a/src/testdir/test_let.vim b/src/testdir/test_let.vim
index fb315e8..9822e6f 100644
--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -8,6 +8,10 @@
   let Test104#numvar = function('tr')
   call assert_equal("function('tr')", string(Test104#numvar))
 
+  let foo#tr = function('tr')
+  call assert_equal("function('tr')", string(foo#tr))
+  unlet foo#tr
+
   let a = 1
   let b = 2