diff --git a/lib/philomena/conversations/conversation.ex b/lib/philomena/conversations/conversation.ex
index 07e3f4ab..ac188f1d 100644
--- a/lib/philomena/conversations/conversation.ex
+++ b/lib/philomena/conversations/conversation.ex
@@ -57,7 +57,7 @@ defmodule Philomena.Conversations.Conversation do
     |> put_recipient()
     |> set_slug()
     |> set_last_message()
-    |> cast_assoc(:messages, with: {Message, :creation_changeset, [from]})
+    |> cast_assoc(:messages, with: &Message.creation_changeset(&1, &2, from))
     |> validate_length(:messages, is: 1)
   end
 
diff --git a/lib/philomena/topics/topic.ex b/lib/philomena/topics/topic.ex
index efc49ce4..0db30126 100644
--- a/lib/philomena/topics/topic.ex
+++ b/lib/philomena/topics/topic.ex
@@ -59,7 +59,7 @@ defmodule Philomena.Topics.Topic do
     |> change(forum: forum, user: attribution[:user])
     |> validate_required(:forum)
     |> cast_assoc(:poll, with: &Poll.update_changeset/2)
-    |> cast_assoc(:posts, with: {Post, :topic_creation_changeset, [attribution, anonymous?]})
+    |> cast_assoc(:posts, with: &Post.topic_creation_changeset(&1, &2, attribution, anonymous?))
     |> validate_length(:posts, is: 1)
     |> unique_constraint(:slug, name: :index_topics_on_forum_id_and_slug)
   end