FIX: When moving topics to an existing topic, say it's an existing topic in the moderator message.

app/assets/javascripts/discourse/templates/modal/merge_topic.js.handlebars

@@ -5,7 +5,6 @@
     </div>
   {{/if}}
 
-  {{selectedPostsCount}}
   <p>{{{i18n topic.merge_topic.instructions count="selectedPostsCount"}}}</p>
 
   {{chooseTopic selectedTopicId=selectedTopicId}}

app/models/post_mover.rb

@@ -1,6 +1,10 @@
 class PostMover
   attr_reader :original_topic, :destination_topic, :user, :post_ids
 
+  def self.move_types
+    @move_types ||= Enum.new(:new_topic, :existing_topic)
+  end
+
   def initialize(original_topic, user, post_ids)
     @original_topic = original_topic
     @user = user
@@ -8,12 +12,16 @@ class PostMover
   end
 
   def to_topic(id)
+    @move_type = PostMover.move_types[:existing_topic]
+
     Topic.transaction do
       move_posts_to Topic.find_by_id(id)
     end
   end
 
   def to_new_topic(title)
+    @move_type = PostMover.move_types[:new_topic]
+
     Topic.transaction do
       move_posts_to Topic.create!(
         user: user,
@@ -94,11 +102,9 @@ class PostMover
   def create_moderator_post_in_original_topic
     original_topic.add_moderator_post(
       user,
-      I18n.t(
+      I18n.t("move_posts.#{PostMover.move_types[@move_type].to_s}_moderator_post",
-        "move_posts.moderator_post",
+             count: post_ids.count,
-        count: post_ids.count,
+             topic_link: "[#{destination_topic.title}](#{destination_topic.url})"),
-        topic_link: "[#{destination_topic.title}](#{destination_topic.url})"
-      ),
       post_number: @first_post_number_moved
     )
   end

config/locales/server.en.yml

@@ -661,9 +661,12 @@ en:
   frequent_poster: "Frequent Poster"
 
   move_posts:
-    moderator_post:
+    new_topic_moderator_post:
       one: "I moved a post to a new topic: %{topic_link}"
       other: "I moved %{count} posts to a new topic: %{topic_link}"
+    existing_topic_moderator_post:
+      one: "I moved a post to an existing topic: %{topic_link}"
+      other: "I moved %{count} posts to an existing topic: %{topic_link}"
 
   topic_statuses:
     archived_enabled: "This topic is now archived. It is frozen and cannot be changed in any way."