diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index a215667..1fe56f3 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2234,6 +2234,12 @@
   call call(test_null_partial(), [])
   call assert_fails('call test_null_function()()', 'E1192:')
   call assert_fails('call test_null_partial()()', 'E117:')
+
+  let lines =<< trim END
+      let Time = 'localtime'
+      call Time()
+  END
+  CheckScriptFailure(lines, 'E1085:')
 endfunc
 
 func Test_char2nr()