no warnings;

my $lex = 4;         # file scoped lexical

#--- normal
# inner scope
sub with_proto ()  { my $lex }

# outer scope
{
  my $lex = 4; 
  sub with_proto() { $lex } 
}

# file scope
sub with_proto()  { $lex }

#--- reference
# inner scope
sub with_proto()  {\ my $lex }

# outer scope
{
  my $lex = 4; 
  sub with_proto() {\ $lex } 
}

# file scope
sub with_proto()  {\ $lex }


#------ lvalue

#--- normal
# inner scope
sub with_proto() :lvalue { my $lex }

# outer scope
{
  my $lex = 4; 
  sub with_proto() :lvalue { $lex } 
}

# file scope
sub with_proto() :lvalue { $lex }

#--- reference
# lvalue references are not feasible, because of
#   "Can't modify single ref constructor in lvalue subroutine"




#------ overriding constant function throws always a warning
sub with_proto () {4} 

# uncommenting garanties a warning
# sub with_proto () {5}