Inline Map.merge/3

Author: devinus

lib/elixir/lib/map.ex

@@ -639,6 +639,8 @@ defmodule Map do
   `map2`). The value returned by `fun` is used as the value under `key` in
   the resulting map.
 
+  Inlined by the compiler.
+
   ## Examples
 
       iex> Map.merge(%{a: 1, b: 2}, %{a: 3, d: 4}, fn _k, v1, v2 ->

lib/elixir/src/elixir_rewrite.erl

@@ -251,6 +251,7 @@ rewrite(Receiver, DotMeta, Right, Meta, Args) ->
 ?rewrite(?map, fetch, [Map, Key], maps, find, [Key, Map]);
 ?rewrite(?map, 'fetch!', [Map, Key], maps, get, [Key, Map]);
 ?rewrite(?map, 'has_key?', [Map, Key], maps, is_key, [Key, Map]);
+?rewrite(?map, merge, [Map1, Map2, Fun], maps, merge_with, [Fun, Map1, Map2]);
 ?rewrite(?map, put, [Map, Key, Value], maps, put, [Key, Value, Map]);
 ?rewrite(?map, 'replace!', [Map, Key, Value], maps, update, [Key, Value, Map]);
 ?rewrite(?port, monitor, [Arg], erlang, monitor, [port, Arg]);