improvement: allow for parent/1 expressions to be resolved "later"

lib/ash/actions/load.ex

@@ -336,6 +336,16 @@ defmodule Ash.Actions.Load do
               value ->
                 Map.put(record, name, value |> List.wrap() |> Enum.at(0))
             end
+
+          :error ->
+            case value do
+              %{__lateral_join_source__: destination_value} when not is_nil(destination_value) ->
+                source_value ==
+                  destination_value
+
+              value ->
+                Map.put(record, name, value |> List.wrap() |> Enum.at(0))
+            end
         end
       end
     end)

lib/ash/filter/filter.ex

@@ -3025,9 +3025,8 @@ defmodule Ash.Filter do
 
   def do_hydrate_refs(%Ash.Query.Parent{expr: expr} = this, context) do
     if !Map.has_key?(context, :parent_stack) || context.parent_stack in [[], nil] do
-      raise "Attempted to use parent expression without a known parent: #{inspect(this)}"
-    end
-
+      {:ok, this}
+    else
       context =
         %{
           context
@@ -3045,6 +3044,7 @@ defmodule Ash.Filter do
           other
       end
     end
+  end
 
   def do_hydrate_refs(
         %Ash.Query.Exists{expr: expr, at_path: at_path, path: path} = exists,