From e6012232efadf1f9c8c91c3fbab4161af18f9b70 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Przemys=C5=82aw=20Wojtasik?=
 <przemyslaw.wojtasik@erlang-solutions.com>
Date: Tue, 24 May 2022 17:02:41 +0200
Subject: [PATCH 1/2] Support typechecking for erlang files from  `src/`
 directory

---
 lib/gradient.ex | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/gradient.ex b/lib/gradient.ex
index 913a851f..e8bae2fc 100644
--- a/lib/gradient.ex
+++ b/lib/gradient.ex
@@ -23,7 +23,8 @@ defmodule Gradient do
   def type_check_file(file, opts \\ []) do
     opts = Keyword.put(opts, :return_errors, true)
 
-    with {:ok, forms} <- ElixirFileUtils.get_forms(file) do
+    with {:ok, forms} <- ElixirFileUtils.get_forms(file),
+         {:elixir, _} <- wrap_language_name(forms) do
       forms = maybe_specify_forms(forms, opts)
 
       case maybe_gradient_check(forms, opts) ++ maybe_gradualizer_check(forms, opts) do
@@ -36,6 +37,12 @@ defmodule Gradient do
           :error
       end
     else
+      {:erlang, forms} ->
+        opts = Keyword.put(opts, :return_errors, false)
+        case maybe_gradualizer_check(forms, opts) do
+          :nok -> :error
+          _ -> :ok
+        end
       error ->
         Logger.error("Can't load file - #{inspect(error)}")
         :error
@@ -74,6 +81,14 @@ defmodule Gradient do
     end
   end
 
+  defp wrap_language_name([{:attribute, _, :file, {file_name, _}} | _] = forms) do
+    if :string.str(file_name, '.erl') > 0 do
+      {:erlang, forms}
+    else
+      {:elixir, forms}
+    end
+  end
+
   defp put_code_path(forms, opts) do
     case opts[:code_path] do
       nil ->

From 87cc585564c5e958faf1a0f82ee4d36a23d342ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Przemys=C5=82aw=20Wojtasik?=
 <przemyslaw.wojtasik@erlang-solutions.com>
Date: Tue, 24 May 2022 19:26:05 +0200
Subject: [PATCH 2/2] Test typechecking erlang and elixir beam files

---
 .gitignore                        |  5 ++++-
 test/examples/erlang/test.erl     |  9 +++++++++
 test/examples/erlang/test_err.erl |  9 +++++++++
 test/gradient_test.exs            | 27 +++++++++++++++++++++++++++
 test/test_helper.exs              | 17 +++++++++++++++++
 5 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 test/examples/erlang/test.erl
 create mode 100644 test/examples/erlang/test_err.erl

diff --git a/.gitignore b/.gitignore
index c3381e7a..3cd1f34d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,8 +25,11 @@ gradient-*.tar
 # Temporary files, for example, from tests.
 /tmp/
 
-# Beam files compiled from examples
+# Elixir beam files compiled from examples
 test/examples/_build/
 
+# Erlang beam files compiled from examples
+test/examples/erlang/_build/
+
 # MacOS DS_Store
 .DS_Store
diff --git a/test/examples/erlang/test.erl b/test/examples/erlang/test.erl
new file mode 100644
index 00000000..597ce5cc
--- /dev/null
+++ b/test/examples/erlang/test.erl
@@ -0,0 +1,9 @@
+-module(test).
+
+-export([positive/1]).
+
+-spec positive(integer()) -> ok | error.
+positive(A) when A > 0 ->
+    ok;
+positive(_) ->
+    error.
diff --git a/test/examples/erlang/test_err.erl b/test/examples/erlang/test_err.erl
new file mode 100644
index 00000000..96296a32
--- /dev/null
+++ b/test/examples/erlang/test_err.erl
@@ -0,0 +1,9 @@
+-module(test_err).
+
+-export([positive/1]).
+
+-spec positive(integer()) -> integer().
+positive(A) when A > 0 ->
+    ok;
+positive(_) ->
+    error.
diff --git a/test/gradient_test.exs b/test/gradient_test.exs
index f3b0fa64..a5cb0530 100644
--- a/test/gradient_test.exs
+++ b/test/gradient_test.exs
@@ -1,4 +1,31 @@
 defmodule GradientTest do
   use ExUnit.Case
   doctest Gradient
+
+  import Gradient.TestHelpers
+  import ExUnit.CaptureIO
+
+  test "typecheck erlang beam" do
+    # typecheck file with errors
+    path = "test/examples/erlang/_build/test_err.beam"
+    erl_path = "test/examples/erlang/test_err.erl"
+    io_data = capture_io(fn -> assert :error = Gradient.type_check_file(path) end)
+    assert String.contains?(io_data, erl_path)
+    # typecheck correct file
+    capture_io(fn ->
+      assert :ok = Gradient.type_check_file("test/examples/erlang/_build/test.beam")
+    end)
+  end
+
+  test "typecheck elixir beam" do
+    # typecheck file with errors
+    path = "test/examples/_build/Elixir.WrongRet.beam"
+    ex_path = "test/examples/type/wrong_ret.ex"
+    io_data = capture_io(fn -> assert :error = Gradient.type_check_file(path) end)
+    assert String.contains?(io_data, ex_path)
+    # typecheck correct file
+    capture_io(fn ->
+      assert :ok = Gradient.type_check_file("test/examples/_build/Elixir.Basic.beam")
+    end)
+  end
 end
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 44a85b4f..4ee4190e 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -1,5 +1,6 @@
 defmodule ExamplesCompiler do
   @build_path "test/examples/_build/"
+  @erl_build_path "test/examples/erlang/_build/"
 
   @version_step 0.01
 
@@ -24,6 +25,20 @@ defmodule ExamplesCompiler do
     end
   end
 
+  def erl_compile(pattern) do
+    case File.mkdir(@erl_build_path) do
+      :ok ->
+        pattern
+        |> Path.wildcard()
+        |> Enum.each(fn p ->
+          :compile.file(to_charlist(p), [:debug_info, {:outdir, to_charlist(@erl_build_path)}])
+        end)
+
+      _ ->
+        :error
+    end
+  end
+
   def excluded_version_tags do
     case @version do
       1.11 ->
@@ -58,4 +73,6 @@ end
 ExamplesCompiler.compile("test/examples/**/*.ex")
 exlcude = ExamplesCompiler.excluded_version_tags()
 
+ExamplesCompiler.erl_compile("test/examples/erlang/**/*.erl")
+
 ExUnit.start(exclude: exlcude)