>type test.pl && perl -MO=Concise,-exec test.pl 2>&1 | find "proto"
sub with_proto()  { \my $lex }
sub without_proto { \my $lex }

with_proto();
without_proto();

4  <#> gv[*with_proto] s         <---- Not constant
8  <#> gv[*without_proto] s      <---- Not constant


>type test.pl && perl -MO=Concise,-exec test.pl 2>&1 | find "proto"
my $lex = 4;
sub with_proto()  { \$lex }
sub without_proto { \$lex }

with_proto();
without_proto();

8  <#> gv[*with_proto] s         <---- Not constant
c  <#> gv[*without_proto] s      <---- Not constant


>type test.pl && perl -MO=Concise,-exec test.pl 2>&1 | find "proto"
{ my $lex = 4; sub with_proto()  { \$lex } }
{ my $lex = 4; sub without_proto { \$lex } }

with_proto();
without_proto();

i  <#> gv[*with_proto] s         <---- Not constant
m  <#> gv[*without_proto] s      <---- Not constant