in reply to Hash assignments using map

What platform and perl version are you on ?

The code runs without warnings, producing hash keys of "c" and "a", as expected, for me:

Summary of my perl5 (revision 5 version 8 subversion 8) configuration: Platform: osname=MSWin32, osvers=5.0, archname=MSWin32-x86-multi-thread

     "A closed mouth gathers no feet." --Unknown