Statisfy Robertcop and Seancop

app/models/merge_request_diff.rb

@@ -135,15 +135,9 @@ class MergeRequestDiff < ActiveRecord::Base
   end
 
   def diff_refs=(new_diff_refs)
-    if new_diff_refs
-      self.base_commit_sha = new_diff_refs.base_sha
-      self.start_commit_sha = new_diff_refs.start_sha
-      self.head_commit_sha = new_diff_refs.head_sha
-    else
-      self.base_commit_sha = nil
-      self.start_commit_sha = nil
-      self.head_commit_sha = nil
-    end
+    self.base_commit_sha = new_diff_refs&.base_sha
+    self.start_commit_sha = new_diff_refs&.start_sha
+    self.head_commit_sha = new_diff_refs&.head_sha
   end
 
   def diff_refs

app/views/projects/merge_requests/show/_versions.html.haml

@@ -81,7 +81,7 @@
         - if @start_sha
           Comments are disabled because you're comparing two versions of this merge request.
         - else
-          Discussions on this old version of the merge request are displayed but comment creation is disabled.
+          Discussions on this version of the merge request are displayed but comment creation is disabled.
 
         .pull-right
           = link_to 'Show latest version', diffs_namespace_project_merge_request_path(@project.namespace, @project, @merge_request), class: 'btn btn-sm'