http://mercurial.selenic.com/bts/issue322

File replaced with directory:

  $ hg init a

  $ cd a

  $ echo a > a

  $ hg commit -Ama

  adding a

  $ rm a

  $ mkdir a

  $ echo a > a/a

Should fail - would corrupt dirstate:

  $ hg add a/a

  abort: file 'a' in dirstate clashes with 'a/a'

  [255]

  $ cd ..

Directory replaced with file:

  $ hg init c

  $ cd c

  $ mkdir a

  $ echo a > a/a

  $ hg commit -Ama

  adding a/a

  $ rm -r a

  $ echo a > a

Should fail - would corrupt dirstate:

  $ hg add a

  abort: directory 'a' already in dirstate

  [255]

  $ cd ..

Directory replaced with file:

  $ hg init d

  $ cd d

  $ mkdir b

  $ mkdir b/c

  $ echo a > b/c/d

  $ hg commit -Ama

  adding b/c/d

  $ rm -r b

  $ echo a > b

Should fail - would corrupt dirstate:

  $ hg add b

  abort: directory 'b' already in dirstate

  [255]