pp.c	TODO

  substr outside of string
    $a = "ab" ; $b = substr($a, 4,5) ;

  Attempt to use reference as lvalue in substr 
    $a = "ab" ; $b = \$a ;  substr($b, 1,1) = $b

  Use of uninitialized value in scalar dereference	[pp_rv2sv()]
	my $a = undef ; my $b = $$a

  Odd number of elements in hash list
	my $a = { 1,2,3 } ;

  Explicit blessing to '' (assuming package main)
	bless \[], "";

  Constant subroutine %s undefined
	sub foo () { 1 }; undef &foo;

  Constant subroutine (anonymous) undefined
	$foo = sub () { 3 }; undef &$foo;

  Use of strings with code points over 0xFF as arguments to 1's complement (~) operator is deprecated. This will be a fatal error in Perl 5.28

  Invalid negative number (%s) in chr

__END__
# pp.c
use warnings 'substr' ;
$a = "ab" ; 
$b = substr($a, 4,5) ;
no warnings 'substr' ;
$a = "ab" ; 
$b = substr($a, 4,5)  ;
EXPECT
substr outside of string at - line 4.
########
# pp.c
use warnings 'substr' ;
$a = "ab" ; 
$b = \$a ;  
substr($b, 1,1) = "ab" ;
$b = \$a;
substr($b, 1,1) = "\x{100}" ;
no warnings 'substr' ;
$b = \$a;
substr($b, 1,1) = "ab" ;
$b = \$a;
substr($b, 1,1) = "\x{100}" ;
EXPECT
Attempt to use reference as lvalue in substr at - line 5.
Attempt to use reference as lvalue in substr at - line 7.
########
# pp.c
use warnings 'misc' ;
@a = qw( a b c );
splice(@a, 4, 0, 'e') ;
@a = qw( a b c );
splice(@a, 4, 1) ;
@a = qw( a b c );
splice(@a, 4) ;
no warnings 'misc' ;
@a = qw( a b c );
splice(@a, 4, 0, 'e') ;
@a = qw( a b c );
splice(@a, 4, 1) ;
@a = qw( a b c );
splice(@a, 4) ;
EXPECT
splice() offset past end of array at - line 4.
splice() offset past end of array at - line 6.
########
# pp.c
use warnings 'uninitialized';
$x = undef; $y = $$x;
no warnings 'uninitialized' ;
$u = undef; $v = $$u;
EXPECT
Use of uninitialized value $x in scalar dereference at - line 3.
########
# pp.c
use warnings 'misc' ;
my $a = { 1,2,3};
no warnings 'misc' ;
my $b = { 1,2,3};
EXPECT
Odd number of elements in anonymous hash at - line 3.
########
# pp.c
use warnings 'misc' ;
bless \[], "" ;
no warnings 'misc' ;
bless \[], "" ;
EXPECT
Explicit blessing to '' (assuming package main) at - line 3.
########
# pp.c
use warnings 'misc';
sub foo () { 1 }
undef &foo;
no warnings 'misc';
sub bar () { 2 }
undef &bar;
EXPECT
Constant subroutine foo undefined at - line 4.
########
# pp.c
use utf8;
use open qw( :utf8 :std );
use warnings 'misc';
sub ฝᶱ () { 1 }
undef &ฝᶱ;
no warnings 'misc';
sub ƚ () { 2 }
undef &ƚ;
EXPECT
Constant subroutine ฝᶱ undefined at - line 6.
########
# pp.c
use warnings 'misc';
$foo = sub () { 3 };
undef &$foo;
no warnings 'misc';
$bar = sub () { 4 };
undef &$bar;
EXPECT
Constant subroutine (anonymous) undefined at - line 4.
########
# pp.c
use utf8 ;
$_ = "\x80  \xff" ;
reverse ;
EXPECT
########
# NAME deprecation of complement with above ff code points
$_ = ~ "\xff";
$_ = ~ "\x{100}";
EXPECT
OPTION regex
Use of strings with code points over 0xFF as arguments to 1's complement \(~\) operator is deprecated. This will be a fatal error in Perl 5.28 at - line \d+.
Use of code point 0xFF+EFF is deprecated; the permissible max is 0x7F+\. This will be fatal in Perl 5\.28 at - line \d+.
########
# NAME chr -1
use warnings 'utf8';
my $chr = chr(-1);
EXPECT
Invalid negative number (-1) in chr at - line 2.