use warnings;
sub RO { warn "RO" }
sub SHAM { warn "SHAM" }
RO();
{ local *RO = sub { warn "BO" }; RO(); }
SHAM();
{ local *SHAM; *SHAM = sub { warn "BO" }; SHAM(); }
RO(); SHAM();
__END__
RO at - line 2.
Subroutine main::RO redefined at - line 5.
BO at - line 5.
SHAM at - line 3.
BO at - line 7.
RO at - line 2.
SHAM at - line 3.

##</code><code>##

Subroutine %s redefined

(W redefine) You redefined a subroutine. To suppress this warning, say

    {
    no warnings 'redefine';
    eval "sub name { ... }";
    }
##</code><code>##

$ perl -le " use warnings; sub foo { warn 1 } foo(); local *foo; sub foo { warn 2 } foo(); "
Subroutine foo redefined at -e line 1.
2 at -e line 1.
Undefined subroutine &main::foo called at -e line 1.

##</code><code>##

$ perl -le " use warnings; sub foo { warn 1 } foo(); local *foo; eval q{sub foo { warn 2 }}; foo(); "
1 at -e line 1.
2 at (eval 5) line 1.
##</code><code>##

$ perl -le " use warnings; sub foo { warn 1 } foo(); { local *foo; eval q{sub foo { warn 2 }}; foo(); } foo(); "
1 at -e line 1.
2 at (eval 5) line 1.
1 at -e line 1.