From 61a3fb803c3babf0e3e750430415338e6506a241 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Sun, 24 Jun 2012 03:47:39 -0500
Subject: [PATCH] add warning for negative argument to chr() [perl #83048]

---
 pp.c        |  3 ++-
 t/uni/chr.t | 11 ++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/pp.c b/pp.c
index 6936b4f..1fcc885 100644
--- a/pp.c
+++ b/pp.c
@@ -3262,7 +3262,8 @@ PP(pp_chr)
 	if (IN_BYTES) {
 	    value = POPu; /* chr(-1) eq chr(0xff), etc. */
 	} else {
-	    (void) POPs; /* Ignore the argument value. */
+	    SV *top = POPs;
+	    Perl_ck_warner(aTHX_ packWARN(WARN_UTF8), "Invalid negative number (%"SVf") in chr", top);
 	    value = UNICODE_REPLACEMENT;
 	}
     } else {
diff --git a/t/uni/chr.t b/t/uni/chr.t
index 33283e7..854d725 100644
--- a/t/uni/chr.t
+++ b/t/uni/chr.t
@@ -8,7 +8,7 @@ BEGIN {
 }
 
 use strict;
-plan (tests => 6);
+plan (tests => 8);
 use encoding 'johab';
 
 ok(chr(0x7f) eq "\x7f");
@@ -19,4 +19,13 @@ for my $i (127, 128, 255) {
     ok(chr($i) eq pack('C', $i));
 }
 
+# [perl #83048]
+{
+    my $w;
+    local $SIG{__WARN__} = sub { $w .= $_[0] };
+    my $chr = chr(-1);
+    is($chr, "\x{fffd}", "invalid values become REPLACEMENT CHARACTER");
+    like($w, qr/^Invalid negative number \(-1\) in chr at /, "with a warning");
+}
+
 __END__
-- 
2.7.4