From 27c1f957d85659b6651a557651d42288c35a0281 Mon Sep 17 00:00:00 2001
From: Fernando Tapia Rico <fertapric@gmail.com>
Date: Sat, 15 Dec 2018 11:14:58 +0100
Subject: [PATCH] Format optional macrocallbacks in IEx.Helpers.b/1

Macrocallbacks are internally stored prefixing them with "MACRO-".
However, that prefix should be removed when presenting the
callback information to the user.
---
 lib/iex/lib/iex/introspection.ex  | 24 ++++++++++++++++++------
 lib/iex/test/iex/helpers_test.exs | 11 +++++++----
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/lib/iex/lib/iex/introspection.ex b/lib/iex/lib/iex/introspection.ex
index bd5e2f0a8d8..0413916cb9f 100644
--- a/lib/iex/lib/iex/introspection.ex
+++ b/lib/iex/lib/iex/introspection.ex
@@ -565,9 +565,9 @@ defmodule IEx.Introspection do
     end
   end
 
-  defp translate_callback({{name, arity}, specs}) do
-    case Atom.to_string(name) do
-      "MACRO-" <> macro_name ->
+  defp translate_callback({name_arity, specs}) do
+    case translate_callback_name_arity(name_arity) do
+      {:macrocallback, _, _} = kind_name_arity ->
         # The typespec of a macrocallback differs from the one expressed
         # via @macrocallback:
         #
@@ -580,10 +580,17 @@ defmodule IEx.Introspection do
             {:type, line1, :fun, [{:type, line2, :product, args}, spec]}
           end)
 
-        {{:macrocallback, String.to_atom(macro_name), arity - 1}, specs}
+        {kind_name_arity, specs}
 
-      _ ->
-        {{:callback, name, arity}, specs}
+      kind_name_arity ->
+        {kind_name_arity, specs}
+    end
+  end
+
+  defp translate_callback_name_arity({name, arity}) do
+    case Atom.to_string(name) do
+      "MACRO-" <> macro_name -> {:macrocallback, String.to_atom(macro_name), arity - 1}
+      _ -> {:callback, name, arity}
     end
   end
 
@@ -599,6 +606,11 @@ defmodule IEx.Introspection do
     optional_callbacks =
       if Code.ensure_loaded?(mod) and function_exported?(mod, :behaviour_info, 1) do
         mod.behaviour_info(:optional_callbacks)
+        |> Enum.map(fn name_arity ->
+          {_kind, name, arity} = translate_callback_name_arity(name_arity)
+          {name, arity}
+        end)
+        |> Enum.sort()
       else
         []
       end
diff --git a/lib/iex/test/iex/helpers_test.exs b/lib/iex/test/iex/helpers_test.exs
index 07828b49e25..49d470a3384 100644
--- a/lib/iex/test/iex/helpers_test.exs
+++ b/lib/iex/test/iex/helpers_test.exs
@@ -725,8 +725,9 @@ defmodule IEx.HelpersTest do
       content = """
       defmodule OptionalCallbacks do
         @doc "callback"
-        @callback optional_1(:foo) :: integer
-        @optional_callbacks optional_1: 1
+        @callback optional_callback(:foo) :: integer
+        @macrocallback optional_macrocallback(:bar) :: atom
+        @optional_callbacks optional_callback: 1, optional_macrocallback: 1
       end
       """
 
@@ -734,9 +735,11 @@ defmodule IEx.HelpersTest do
         assert c(filename, ".") == [OptionalCallbacks]
 
         assert capture_io(fn -> b(OptionalCallbacks) end) =~ """
-               @callback optional_1(:foo) :: integer()
+               @callback optional_callback(:foo) :: integer()
 
-               @optional_callbacks [optional_1: 1]
+               @macrocallback optional_macrocallback(:bar) :: atom()
+
+               @optional_callbacks [optional_callback: 1, optional_macrocallback: 1]
 
                """
       end)