--- a/hg.rst	Tue Nov 25 19:25:39 2014 +0200
+++ b/hg.rst	Tue Nov 25 20:31:12 2014 +0200
@@ -73,6 +73,14 @@
   ; Enable '.hgeol' tracking (fix for CR/LF).
   hgext.eol =
 
+Show diff against 2 parents or base during merge.
+=================================================
+::
+
+  hg diff -r 'p1()'
+  hg diff -r 'p2()'
+  hg diff -r 'ancestor(p1(), p2())'
+
 Downgrade repository format.
 ============================