The question is that if you have a handler opened Perl will treat it as a IO::Handle object:

package ALIAS ;

sub close { print "CLOSE>> @_\n" ; }

package main ;

 open(ALIAS , ">&STDIN") ;

 ALIAS->close() ;
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This will produce the IO::Handle error, but if you remove the open() line, ALIAS will work as a package name. So, this is not a reserved word problem!