Require Erlang/OTP 22+

Author: josevalim

README.md

@@ -48,10 +48,10 @@ If Elixir fails to build (specifically when pulling in a new version via
 If tests pass, you can use Interactive Elixir by running `bin/iex` in your terminal.
 
 However, if tests fail, it is likely that you have an outdated Erlang/OTP version
-(Elixir requires Erlang/OTP 21.0 or later). You can check your Erlang/OTP version
+(Elixir requires Erlang/OTP 22.0 or later). You can check your Erlang/OTP version
 by calling `erl` in the command line. You will see some information similar to:
 
-    Erlang/OTP 21 [erts-9.0] [smp:2:2] [async-threads:10] [kernel-poll:false]
+    Erlang/OTP 22 [erts-9.0] [smp:2:2] [async-threads:10] [kernel-poll:false]
 
 If you have properly set up your dependencies and tests still fail,
 you may want to open up a bug report, as explained next.

lib/elixir/lib/application.ex

@@ -694,9 +694,6 @@ defmodule Application do
     :application.set_env(app, key, value, opts)
   end
 
-  # TODO: Remove this once we support Erlang/OTP 22+ exclusively.
-  @compile {:no_warn_undefined, {:application, :set_env, 2}}
-
   @doc """
   Puts the environment for multiple apps at the same time.
 
@@ -705,28 +702,14 @@ defmodule Application do
     * have the same application listed more than once
     * have the same key inside the same application listed more than once
 
-  If those conditions are not met, the behaviour is undefined
-  (on Erlang/OTP 21 and earlier) or will raise (on Erlang/OTP 22
-  and later).
+  If those conditions are not met, it will raise.
 
   It receives the same options as `put_env/4`. Returns `:ok`.
   """
   @doc since: "1.9.0"
   @spec put_all_env([{app, [{key, value}]}], timeout: timeout, persistent: boolean) :: :ok
   def put_all_env(config, opts \\ []) when is_list(config) and is_list(opts) do
-    # TODO: Remove function exported? check when we require Erlang/OTP 22+
-    if function_exported?(:application, :set_env, 2) do
-      :application.set_env(config, opts)
-    else
-      for app_keyword <- config,
-          {app, keyword} = app_keyword,
-          key_value <- keyword,
-          {key, value} = key_value do
-        :application.set_env(app, key, value, opts)
-      end
-
-      :ok
-    end
+    :application.set_env(config, opts)
   end
 
   @doc """

lib/elixir/lib/gen_server.ex

@@ -585,8 +585,6 @@ defmodule GenServer do
 
   This callback is optional. If one is not implemented, the server will fail
   if a continue instruction is used.
-
-  This callback is only supported on Erlang/OTP 21+.
   """
   @callback handle_continue(continue :: term, state :: term) ::
               {:noreply, new_state}
@@ -1038,18 +1036,8 @@ defmodule GenServer do
   is unknown whether the destination `server` successfully
   handled the message.
 
-  `c:handle_cast/2` will be called on the server to handle
-  the request. In case the `server` is on a node which is
-  not yet connected to the caller one, the semantics differ
-  depending on the used Erlang/OTP version.
-
   `server` can be any of the values described in the "Name registration"
   section of the documentation for this module.
-
-  Before Erlang/OTP 21, the call is going to block until a
-  connection happens. This was done to guarantee ordering.
-  Starting with Erlang/OTP 21, both Erlang and Elixir do
-  not block the call.
   """
   @spec cast(server, term) :: :ok
   def cast(server, request)

lib/elixir/lib/integer.ex

@@ -318,18 +318,17 @@ defmodule Integer do
 
   defp count_digits_nosign(<<_::bits>>, _, count), do: count
 
-  # TODO: Remove Integer.to_string/1 once the minimum supported version is
-  #       Erlang/OTP 22, since it is covered by the now BIF Integer.to_string/2.
-  #       Please reapply commit 2622fd6b0aa419a983a899a1fbdb5deefba3d85d.
   @doc """
   Returns a binary which corresponds to the text representation
   of `integer` in the given `base`.
 
-  `base` can be an integer between 2 and 36. If no `base` is given, it defaults to `10`.
+  `base` can be an integer between 2 and 36. If no `base` is given,
+  it defaults to `10`.
 
   Inlined by the compiler.
 
   ## Examples
+
       iex> Integer.to_string(123)
       "123"
 
@@ -357,13 +356,12 @@ defmodule Integer do
     :erlang.integer_to_binary(integer, base)
   end
 
-  # TODO: Remove Integer.to_charlist/1 once the minimum supported version is
-  #       Erlang/OTP 22, since it is covered by the now BIF Integer.to_charlist/2.
-  #       Please reapply commit 2622fd6b0aa419a983a899a1fbdb5deefba3d85d.
   @doc """
-  Returns a charlist which corresponds to the text representation of `integer` in the given `base`.
+  Returns a charlist which corresponds to the text representation
+  of `integer` in the given `base`.
 
-  `base` can be an integer between 2 and 36. If no `base` is given, it defaults to `10`.
+  `base` can be an integer between 2 and 36. If no `base` is given,
+  it defaults to `10`.
 
   Inlined by the compiler.
 

lib/iex/lib/iex.ex

@@ -312,7 +312,7 @@ defmodule IEx do
   results in:
 
       $ iex
-      Erlang/OTP 21 [...]
+      Erlang/OTP 22 [...]
 
       hello world
       Interactive Elixir - press Ctrl+C to exit (type h() ENTER for help)
@@ -336,7 +336,7 @@ defmodule IEx do
   Now run the shell:
 
       $ iex
-      Erlang/OTP 21 [...]
+      Erlang/OTP 22 [...]
 
       Interactive Elixir - press Ctrl+C to exit (type h() ENTER for help)
       iex(1)> [1, 2, 3, 4, 5]

lib/logger/lib/logger/translator.ex

@@ -34,8 +34,6 @@ defmodule Logger.Translator do
   """
   def translate(min_level, level, kind, message)
 
-  ## Erlang/OTP 21 and after
-
   def translate(min_level, _level, :report, {:logger, %{label: label} = report}) do
     case label do
       {:gen_server, :terminate} ->