https://bz.mercurial-scm.org/612

  $ hg init repo

  $ cd repo

  $ mkdir src

  $ echo a > src/a.c

  $ hg ci -Ama

  adding src/a.c

  $ hg mv src source

  moving src/a.c to source/a.c

  $ hg ci -Ammove

  $ hg co -C 0

  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo new > src/a.c

  $ echo compiled > src/a.o

  $ hg ci -mupdate

  created new head

  $ hg status

  ? src/a.o

  $ hg merge

  merging src/a.c and source/a.c to source/a.c

  0 files updated, 1 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg status

  M source/a.c

  R src/a.c

  ? src/a.o