patch 7.4.1580
Problem:    Crash when using function reference. (Luchr)
Solution:   Set initial refcount. (Ken Takata, closes #690)
diff --git a/src/testdir/test_partial.vim b/src/testdir/test_partial.vim
index ddc85e0..acba887 100644
--- a/src/testdir/test_partial.vim
+++ b/src/testdir/test_partial.vim
@@ -68,3 +68,17 @@
 
   call assert_fails('call function(dict.MyFunc, ["bbb"], dict)', 'E924:')
 endfunc
+
+fun InnerCall(funcref)
+  return a:funcref
+endfu
+
+fun OuterCall()
+  let opt = { 'func' : function('sin') }
+  call InnerCall(opt.func)
+endfu
+
+func Test_function_in_dict()
+  call OuterCall()
+endfunc
+