in reply to Re^10: Constant subroutine main::C redefined
in thread Constant subroutine main::C redefined

String eval for sub definition might be helpful here, though I don't know if that messes with the optimization. Minus that, 
sub FOO(){23}; 
BEGIN{eval sprintf 'delete $%s::{FOO}', __PACKAGE__}
sub FOO(){42};

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might hit your need.

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

In Section Seekers of Perl Wisdom