$ echo "[extensions]" >> $HGRCPATH

  $ echo "mq=" >> $HGRCPATH

  $ hg init a

  $ cd a

  $ echo a > a

  $ hg ci -Ama

  adding a

  $ hg qnew a.patch

  $ echo a >> a

  $ hg qrefresh

  $ hg qnew b.patch

  $ echo b > b

  $ hg add b

  $ hg qrefresh

  $ hg qnew c.patch

  $ echo c > c

  $ hg add c

  $ hg qrefresh

  $ hg qgoto a.patch

  popping c.patch

  popping b.patch

  now at: a.patch

  $ hg qgoto c.patch

  applying b.patch

  applying c.patch

  now at: c.patch

  $ hg qgoto b.patch

  popping c.patch

  now at: b.patch

Using index:

  $ hg qgoto 0

  popping b.patch

  now at: a.patch

  $ hg qgoto 2

  applying b.patch

  applying c.patch

  now at: c.patch

No warnings when using index:

  $ hg qnew bug314159

  $ echo d >> c

  $ hg qrefresh

  $ hg qnew bug141421

  $ echo e >> c

  $ hg qrefresh

  $ hg qgoto 1

  popping bug141421

  popping bug314159

  popping c.patch

  now at: b.patch

  $ hg qgoto 3

  applying c.patch

  applying bug314159

  now at: bug314159

Detect ambiguous non-index:

  $ hg qgoto 14

  patch name "14" is ambiguous:

    bug314159

    bug141421

  abort: patch 14 not in series

  [255]