patch 8.2.5117: crash when calling a Lua callback from a :def function

Problem:    Crash when calling a Lua callback from a :def function. (Bohdan
            Makohin)
Solution:   Handle FC_CFUNC in call_user_func_check(). (closes #10587)

src/testdir/test_lua.vim

@@ -664,6 +664,17 @@ func Test_lua_blob()
         \ '[string "vim chunk"]:1: string expected, got table')
 endfunc
 
+def Vim9Test(Callback: func())
+  Callback()
+enddef
+
+func Test_call_lua_func_from_vim9_func()
+  " this only tests that Vim doesn't crash
+  lua << EOF
+vim.fn.Vim9Test(function () print('Hello') end)
+EOF
+endfunc
+
 func Test_lua_funcref()
   function I(x)
     return a:x

src/userfunc.c

@@ -3021,6 +3021,15 @@ call_user_func_check(
 {
     int error;
 
+#ifdef FEAT_LUA
+    if (fp->uf_flags & FC_CFUNC)
+    {
+	cfunc_T cb = fp->uf_cb;
+
+	return (*cb)(argcount, argvars, rettv, fp->uf_cb_state);
+    }
+#endif
+
     if (fp->uf_flags & FC_RANGE && funcexe->fe_doesrange != NULL)
 	*funcexe->fe_doesrange = TRUE;
     error = check_user_func_argcount(fp, argcount);
@@ -3584,14 +3593,6 @@ call_func(
 
 	    if (fp != NULL && (fp->uf_flags & FC_DELETED))
 		error = FCERR_DELETED;
-#ifdef FEAT_LUA
-	    else if (fp != NULL && (fp->uf_flags & FC_CFUNC))
-	    {
-		cfunc_T cb = fp->uf_cb;
-
-		error = (*cb)(argcount, argvars, rettv, fp->uf_cb_state);
-	    }
-#endif
 	    else if (fp != NULL)
 	    {
 		if (funcexe->fe_argv_func != NULL)

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5117,
 /**/
     5116,
 /**/