ksh bug on function aliasing

[Oin]

Here is a bug I've found in ksh @(#)Version 06/03/86.
I declared a function chdir() for the shell builtin cd and
aliased cd to be chdir() ( see script below for details ).
Now have a look at the following two different behaviours of ksh:

Situation 1:
  declare function
  declare alias
  call alias
  everything's fine...


  305 $ chdir ()
  >>> {
  >>> unalias cd
  >>> cd $*
  >>> PS1="${PWD} ! \$ "
  >>> alias cd=chdir
  >>> }
  306 $ alias cd=chdir
  307 $ cd /tmp
  /tmp 308 $ cd /usr/include
  /usr/include 309 $ type cd
  cd is an alias for chdir
  /usr/include 310 $ type chdir
  chdir is a function
  /usr/include 311 $ typeset -f chdir
  function chdir
  {
  unalias cd
  cd $*
  PS1="${PWD} ! \$ "
  alias cd=chdir
  }

Situation 2:
  declare alias
  declare function
  call alias
  @#$%%^&*


  /usr/include 312 $ chdir ()
  >>> {
  >>> unalias cd
  >>> cd $*
  >>> PS1="${PWD} ! \$ "
  >>> PS2="${PWD} >>> "
  >>> alias cd=chdir
  >>> }
  /usr/include 313 $ type cd
  cd is an alias for chdir
  /usr/include 314 $ type chdir
  chdir is a function
  /usr/include 315 $ typeset -f chdir
  function chdir
  {
  unalias cd
  cd $*
  PS1="${PWD} ! \$ "
  PS2="${PWD} >>> "
  alias cd=chdir
  }
  /usr/include 316 $ cd /
  sh: chdir: recursive call



  Franz "Oin" Schmausser            local: lan.informatik.tu-muenchen.dbp.de 
  TU Muenchen, Inst. f. Informatik    DFN: schmauss@{local}                  
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  D-8000 Muenchen                 ARPA/CS: schmauss%{local}@relay.cs.net