diff --git a/mercurial/context.py b/mercurial/context.py
--- a/mercurial/context.py
+++ b/mercurial/context.py
@@ -2879,6 +2879,9 @@
 
         return scmutil.status(modified, added, removed, [], [], [], [])
 
+    def mergestate(self):
+        return mergestatemod.memmergestate(self._repo, self)
+
 
 class memfilectx(committablefilectx):
     """memfilectx represents an in-memory file to commit.