Remove warnings for docs in the same clause

Unfortunately this leads to false positives when trying
to override the docs of an overridable definition.

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: José Valim

lib/elixir/lib/module.ex

@@ -1331,16 +1331,6 @@ defmodule Module do
 
       [{_, current_line, current_sign, current_doc, current_doc_meta}] ->
         signature = merge_signatures(current_sign, signature, 1)
-
-        if is_binary(doc) and is_binary(current_doc) and not is_nil(body) do
-          message =
-            "redefining @doc attribute previously set at line #{current_line}. " <>
-              "If you want to redefine a previously specified doc, " <>
-              "use a definition without a body after the original documentation"
-
-          :elixir_errors.warn(line, env.file, message)
-        end
-
         doc = if is_nil(doc), do: current_doc, else: doc
         doc = if is_nil(doc) && impl, do: false, else: doc
         doc_meta = Map.merge(current_doc_meta, doc_meta)

lib/elixir/test/elixir/kernel/warning_test.exs

@@ -1109,34 +1109,6 @@ defmodule Kernel.WarningTest do
     purge(Sample)
   end
 
-  test "duplicated docs across multiple clauses" do
-    output =
-      capture_err(fn ->
-        Code.eval_string("""
-        defmodule Sample do
-          @doc "Something"
-          def foo(a)
-
-          @doc "Something"
-          def foo(1), do: :ok
-
-          @doc "Something"
-          def foo(2), do: :ok
-
-          @doc "Something"
-          def foo(a)
-        end
-        """)
-      end)
-
-    assert output =~ "redefining @doc attribute previously set at line 2"
-    assert output =~ "nofile:5"
-    assert output =~ "nofile:8"
-    refute output =~ "nofile:11"
-  after
-    purge(Sample)
-  end
-
   test "reserved doc metadata keys" do
     output =
       capture_err(fn ->