Reduce the amount of generated code for defdelegate

2 files changed, 34 insertions, 27 deletions

diff --git a/lib/elixir/lib/kernel.ex b/lib/elixir/lib/kernel.ex
index 47c58565a..abf4140ff 100644
--- a/lib/elixir/lib/kernel.ex
+++ b/lib/elixir/lib/kernel.ex
@@ -5559,33 +5559,11 @@ defmodule Kernel do
       end
 
     quote bind_quoted: [funs: funs, opts: opts] do
-      target =
-        Keyword.get(opts, :to) || raise ArgumentError, "expected to: to be given as argument"
-
-      as = Keyword.get(opts, :as)
-
-      if target == __MODULE__ and is_nil(as) do
-        raise ArgumentError,
-              "defdelegate function is calling itself, which will lead to an infinite loop. You should either change the value of the :to option or specify the :as option"
-      end
-
-      if is_list(funs) do
-        IO.warn(
-          "passing a list to Kernel.defdelegate/2 is deprecated, please define each delegate separately",
-          Macro.Env.stacktrace(__ENV__)
-        )
-      end
-
-      if Keyword.has_key?(opts, :append_first) do
-        IO.warn(
-          "Kernel.defdelegate/2 :append_first option is deprecated",
-          Macro.Env.stacktrace(__ENV__)
-        )
-      end
+      target = Kernel.Utils.defdelegate_all(funs, opts, __ENV__)
 
+      # TODO: Remove List.wrap when multiple funs are no longer supported
       for fun <- List.wrap(funs) do
-        {name, args, as, as_args} = Kernel.Utils.defdelegate(fun, opts)
-
+        {name, args, as, as_args} = Kernel.Utils.defdelegate_each(fun, opts)
         @doc delegate_to: {target, as, :erlang.length(as_args)}
 
         # Build the call AST by hand so it doesn't get a
diff --git a/lib/elixir/lib/kernel/utils.ex b/lib/elixir/lib/kernel/utils.ex
index b57f65dd8..7811828e9 100644
--- a/lib/elixir/lib/kernel/utils.ex
+++ b/lib/elixir/lib/kernel/utils.ex
@@ -22,9 +22,38 @@ defmodule Kernel.Utils do
   defp destructure_nil(count), do: [nil | destructure_nil(count - 1)]
 
   @doc """
-  Callback for defdelegate.
+  Callback for defdelegate entry point.
   """
-  def defdelegate(fun, opts) when is_list(opts) do
+  def defdelegate_all(funs, opts, env) do
+    to = Keyword.get(opts, :to) || raise ArgumentError, "expected to: to be given as argument"
+    as = Keyword.get(opts, :as)
+
+    if to == env.module and is_nil(as) do
+      raise ArgumentError,
+            "defdelegate function is calling itself, which will lead to an infinite loop. You should either change the value of the :to option or specify the :as option"
+    end
+
+    if is_list(funs) do
+      IO.warn(
+        "passing a list to Kernel.defdelegate/2 is deprecated, please define each delegate separately",
+        Macro.Env.stacktrace(env)
+      )
+    end
+
+    if Keyword.has_key?(opts, :append_first) do
+      IO.warn(
+        "Kernel.defdelegate/2 :append_first option is deprecated",
+        Macro.Env.stacktrace(env)
+      )
+    end
+
+    to
+  end
+
+  @doc """
+  Callback for each function in defdelegate.
+  """
+  def defdelegate_each(fun, opts) when is_list(opts) do
     # TODO: Remove on v2.0
     append_first? = Keyword.get(opts, :append_first, false)