Fix issue with macro expansion in over clause's order_by

lib/ecto/query/builder/order_by.ex

@@ -75,13 +75,13 @@ defmodule Ecto.Query.Builder.OrderBy do
 
   defp do_escape({dir, expr}, params_acc, kind, vars, env) do
     fun = &escape_expansion(kind, &1, &2, &3, &4, &5)
-    {ast, params_acc} = Builder.escape(expr, :any, params_acc, vars, {env, fun})
+    {ast, params_acc} = Builder.escape(expr, :any, params_acc, vars, {get_env(env), fun})
     {[{quoted_dir!(kind, dir), ast}], params_acc}
   end
 
   defp do_escape(expr, params_acc, kind, vars, env) do
     fun = &escape_expansion(kind, &1, &2, &3, &4, &5)
-    {ast, params_acc} = Builder.escape(expr, :any, params_acc, vars, {env, fun})
+    {ast, params_acc} = Builder.escape(expr, :any, params_acc, vars, {get_env(env), fun})
 
     if is_list(ast) do
       {ast, params_acc}
@@ -90,6 +90,9 @@ defmodule Ecto.Query.Builder.OrderBy do
     end
   end
 
+  defp get_env({env, _}), do: env
+  defp get_env(env), do: env
+
   defp escape_expansion(kind, expr, _type, params_acc, vars, env) when is_list(expr) do
     escape(kind, expr, params_acc, vars, env)
   end

test/ecto/query/builder/select_test.exs

@@ -1,10 +1,14 @@
+Code.require_file("../builder_test.exs", __DIR__)
+
 defmodule Ecto.Query.Builder.SelectTest do
   use ExUnit.Case, async: true
 
   import Ecto.Query
   import Ecto.Query.Builder.Select
   doctest Ecto.Query.Builder.Select
 
+  import Ecto.Query.BuilderTest, only: [my_custom_field: 1, my_complex_order: 1]
+
   defmodule Post do
     defstruct [:title]
   end
@@ -174,6 +178,41 @@ defmodule Ecto.Query.Builder.SelectTest do
       assert %{alias: _} = query.select.aliases
     end
 
+    test "supports macro expansion in over/2" do
+      query = from p in "posts", select: %{row_number: over(row_number(), order_by: [desc: my_custom_field(p)])}
+
+      assert {:%{}, [],
+       [
+         row_number:
+           {:over, [],
+            [
+              {:row_number, [], []},
+              [
+                order_by: [
+                  desc: {:fragment, [], [raw: "lower(", expr: _, raw: ")"]}
+                ]
+              ]
+            ]}
+       ]} = query.select.expr
+
+      query = from p in "posts", select: %{row_number: over(row_number(), order_by: my_complex_order(p))}
+      assert {:%{}, [],
+        [
+          row_number:
+            {:over, [],
+              [
+                {:row_number, [], []},
+                [
+                  order_by: [
+                    desc: _,
+                    asc: {:fragment, [], [raw: "lower(", expr: _, raw: ")"]},
+                    asc: {:nth_value, [], _}
+                  ]
+                ]
+              ]}
+        ]} = query.select.expr
+    end
+
     test "raises if name given to selected_as/2 is not an atom" do
       message = "expected literal atom or interpolated value in selected_as/2, got: `\"ident\"`"