diff --git a/src/eval.c b/src/eval.c
index 8db2a15..25785b7 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -10157,6 +10157,62 @@
 }
 
 /*
+ * Go over all entries in "d2" and add them to "d1".
+ * When "action" is "error" then a duplicate key is an error.
+ * When "action" is "force" then a duplicate key is overwritten.
+ * Otherwise duplicate keys are ignored ("action" is "keep").
+ */
+    void
+dict_extend(d1, d2, action)
+    dict_T	*d1;
+    dict_T	*d2;
+    char_u	*action;
+{
+    dictitem_T	*di1;
+    hashitem_T	*hi2;
+    int		todo;
+
+    todo = (int)d2->dv_hashtab.ht_used;
+    for (hi2 = d2->dv_hashtab.ht_array; todo > 0; ++hi2)
+    {
+	if (!HASHITEM_EMPTY(hi2))
+	{
+	    --todo;
+	    di1 = dict_find(d1, hi2->hi_key, -1);
+	    if (d1->dv_scope != 0)
+	    {
+		/* Disallow replacing a builtin function in l: and g:.
+		 * Check the key to be valid when adding to any
+		 * scope. */
+		if (d1->dv_scope == VAR_DEF_SCOPE
+			&& HI2DI(hi2)->di_tv.v_type == VAR_FUNC
+			&& var_check_func_name(hi2->hi_key,
+							 di1 == NULL))
+		    break;
+		if (!valid_varname(hi2->hi_key))
+		    break;
+	    }
+	    if (di1 == NULL)
+	    {
+		di1 = dictitem_copy(HI2DI(hi2));
+		if (di1 != NULL && dict_add(d1, di1) == FAIL)
+		    dictitem_free(di1);
+	    }
+	    else if (*action == 'e')
+	    {
+		EMSG2(_("E737: Key already exists: %s"), hi2->hi_key);
+		break;
+	    }
+	    else if (*action == 'f' && HI2DI(hi2) != di1)
+	    {
+		clear_tv(&di1->di_tv);
+		copy_tv(&HI2DI(hi2)->di_tv, &di1->di_tv);
+	    }
+	}
+    }
+}
+
+/*
  * "extend(list, list [, idx])" function
  * "extend(dict, dict [, action])" function
  */
@@ -10206,12 +10262,9 @@
     }
     else if (argvars[0].v_type == VAR_DICT && argvars[1].v_type == VAR_DICT)
     {
-	dict_T		*d1, *d2;
-	dictitem_T	*di1;
-	char_u		*action;
-	int		i;
-	hashitem_T	*hi2;
-	int		todo;
+	dict_T	*d1, *d2;
+	char_u	*action;
+	int	i;
 
 	d1 = argvars[0].vval.v_dict;
 	d2 = argvars[1].vval.v_dict;
@@ -10238,46 +10291,7 @@
 	    else
 		action = (char_u *)"force";
 
-	    /* Go over all entries in the second dict and add them to the
-	     * first dict. */
-	    todo = (int)d2->dv_hashtab.ht_used;
-	    for (hi2 = d2->dv_hashtab.ht_array; todo > 0; ++hi2)
-	    {
-		if (!HASHITEM_EMPTY(hi2))
-		{
-		    --todo;
-		    di1 = dict_find(d1, hi2->hi_key, -1);
-		    if (d1->dv_scope != 0)
-		    {
-			/* Disallow replacing a builtin function in l: and g:.
-			 * Check the key to be valid when adding to any
-			 * scope. */
-		        if (d1->dv_scope == VAR_DEF_SCOPE
-				&& HI2DI(hi2)->di_tv.v_type == VAR_FUNC
-				&& var_check_func_name(hi2->hi_key,
-								 di1 == NULL))
-			    break;
-			if (!valid_varname(hi2->hi_key))
-			    break;
-		    }
-		    if (di1 == NULL)
-		    {
-			di1 = dictitem_copy(HI2DI(hi2));
-			if (di1 != NULL && dict_add(d1, di1) == FAIL)
-			    dictitem_free(di1);
-		    }
-		    else if (*action == 'e')
-		    {
-			EMSG2(_("E737: Key already exists: %s"), hi2->hi_key);
-			break;
-		    }
-		    else if (*action == 'f' && HI2DI(hi2) != di1)
-		    {
-			clear_tv(&di1->di_tv);
-			copy_tv(&HI2DI(hi2)->di_tv, &di1->di_tv);
-		    }
-		}
-	    }
+	    dict_extend(d1, d2, action);
 
 	    copy_tv(&argvars[0], rettv);
 	}