Indicate reverted status of a merge request on it's individual page

app/models/commit.rb

@@ -428,6 +428,10 @@ class Commit
   end
 
   def has_been_reverted?(current_user, notes_association = nil)
+    !!reverting_commit(current_user, notes_association)
+  end
+
+  def reverting_commit(current_user, notes_association = nil)
     ext = Gitlab::ReferenceExtractor.new(project, current_user)
     notes_association ||= notes_with_associations
 
@@ -435,7 +439,7 @@ class Commit
       note.all_references(current_user, extractor: ext)
     end
 
-    ext.commits.any? { |commit_ref| commit_ref.reverts_commit?(self, current_user) }
+    ext.commits.find { |commit_ref| commit_ref.reverts_commit?(self, current_user) }
   end
 
   def change_type_title(user)

app/models/merge_request.rb

@@ -1576,6 +1576,28 @@ class MergeRequest < ApplicationRecord
     !merge_commit.has_been_reverted?(current_user, notes_association)
   end
 
+  def is_reverted?(current_user)
+    !!reverting_merge_request(current_user)
+  end
+
+  def reverting_merge_request(current_user)
+    return nil unless merge_commit
+    return nil unless merged_at
+
+    cutoff = merged_at - 1.minute
+
+    notes_association = notes_with_associations.where('created_at >= ?', cutoff)
+
+    reverting_commit = merge_commit.reverting_commit(current_user, notes_association)
+
+    MergeRequestsFinder.new(
+      current_user,
+      project_id: project.id,
+      commit_sha: reverting_commit.sha,
+      state: 'merged'
+    ).execute.first if reverting_commit
+  end
+
   def merged_at
     strong_memoize(:merged_at) do
       next unless merged?

app/views/projects/merge_requests/_mr_title.html.haml

@@ -14,8 +14,13 @@
   .detail-page-header-body
     .issuable-status-box.status-box{ class: status_box_class(@merge_request) }
       = sprite_icon(state_icon_name, css_class: 'd-block d-sm-none')
-      %span.d-none.d-sm-block
-        = state_human_name
+      - if @merge_request.is_reverted?(current_user)
+        %span.d-none.d-sm-block
+          = _("Merged")
+          = link_to '(reverted)', merge_request_path(@merge_request.reverting_merge_request(current_user))
+      - else
+        %span.d-none.d-sm-block
+          = state_human_name
 
     .issuable-meta
       #js-issuable-header-warnings