Do not break signatures over multiple lines

Author: josevalim

lib/elixir/src/elixir_erl.erl

@@ -552,7 +552,9 @@ signature_to_binary(Module, '__struct__', []) ->
   <<"%", ('Elixir.Kernel':inspect(Module))/binary, "{}">>;
 
 signature_to_binary(_, Name, Signature) ->
-  'Elixir.Macro':to_string({Name, [{closing, []}], Signature}).
+  Quoted = {Name, [{closing, []}], Signature},
+  Doc = 'Elixir.Inspect.Algebra':format('Elixir.Code':quoted_to_algebra(Quoted), infinity),
+  'Elixir.IO':iodata_to_binary(Doc).
 
 checker_chunk(#{definitions := Definitions, deprecated := Deprecated, is_behaviour := IsBehaviour}) ->
   DeprecatedMap = maps:from_list(Deprecated),

lib/elixir/test/elixir/kernel/docs_test.exs

@@ -119,6 +119,14 @@ defmodule Kernel.DocsTest do
 
           def two_good_names(first, :ok), do: first
           def two_good_names(second, :error), do: second
+
+          def really_long_signature(
+                really_long_var_named_one,
+                really_long_var_named_two,
+                really_long_var_named_three
+              ) do
+            {really_long_var_named_one, really_long_var_named_two, really_long_var_named_three}
+          end
         end
       )
 
@@ -128,6 +136,7 @@ defmodule Kernel.DocsTest do
       assert [
                arg_names,
                only_underscore,
+               really_long_signature,
                two_good_names,
                with_defaults,
                with_map_and_default,
@@ -141,6 +150,12 @@ defmodule Kernel.DocsTest do
       # only_underscore/1
       assert {{:only_underscore, 1}, ["only_underscore(_)"]} = only_underscore
 
+      # really_long_signature/3
+      assert {{:really_long_signature, 3},
+              [
+                "really_long_signature(really_long_var_named_one, really_long_var_named_two, really_long_var_named_three)"
+              ]} = really_long_signature
+
       # two_good_names/2
       assert {{:two_good_names, 2}, ["two_good_names(first, atom)"]} = two_good_names