Add a regression test for bug #23765 (by Jarkko)

p4raw-id: //depot/perl@22976

diff --git a/t/op/substr.t b/t/op/substr.t
index 08f4165..9549d29 100755 (executable)
--- a/t/op/substr.t
+++ b/t/op/substr.t
@@ -1,6 +1,6 @@
 #!./perl
 
-print "1..189\n";
+print "1..190\n";
 
 #P = start of string  Q = start of substr  R = end of substr  S = end of string
 
@@ -651,3 +651,10 @@ ok 174, $x eq "\x{100}\x{200}\xFFb";
     ok 189, substr($text,$pos,1) eq $pos;
 
 }
+
+# [perl #23765]
+{
+    my $a = pack("C", 0xbf);
+    substr($a, -1) &= chr(0xfeff);
+    ok 190, $a eq "\xbf";
+}