$ perl -e'use strict; our $x=$x;'
$ perl -e'use strict; our $x=qr/(??{ $x })/;'
Variable "$x" is not imported at (re_eval 1) line 2.
Global symbol "$x" requires explicit package name at (re_eval 1) line 2.
Compilation failed in regexp at -e line 1.
$ perl -e'use strict; my $x = qr/(??{ $x })/;'
Global symbol "$x" requires explicit package name at (re_eval 1) line 2.
Compilation failed in regexp at -e line 1.