The function Encode::Repair::repair_double fixes the character U+201C LEFT DOUBLE QUOTATION MARK when double-encoded but not its companion character U+201D RIGHT DOUBLE QUOTATION MARK when double-encoded. Is there a bug in the module or a defect in my expectations? Or is something else wrong?

Here's a script that demonstrates the problem:

use v5.14;
use strict;
use warnings;

use charnames qw( :full );
use Encode qw( encode decode );
use Encode::Repair qw( repair_double );

binmode STDOUT, ':encoding(UTF-8)';

my $ldqm = "\N{LEFT DOUBLE QUOTATION MARK}";
my $rdqm = "\N{RIGHT DOUBLE QUOTATION MARK}";

$ldqm = encode('UTF-8', decode('Windows-1252', encode('UTF-8', $ldqm))
+);
$rdqm = encode('UTF-8', decode('Windows-1252', encode('UTF-8', $rdqm))
+);

say repair_double($ldqm, { via => 'Windows-1252' });
say repair_double($rdqm, { via => 'Windows-1252' });

__END__

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Here's the output of the script piped through od:

C:\>perl demo.pl | od -h
0000000000    E2  80  9C  0D  0A  EF  BF  BD  EF  BF  BD  3F  0D  0A
0000000016

C:\>

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E2 80 9C is the correct UTF-8 encoding of the Unicode character U+201C LEFT DOUBLE QUOTATION MARK.

EF BF BD is U+FFFD REPLACEMENT CHARACTER and 3F is U+003F QUESTION MARK. I expect the output to be the single Unicode character U+201D RIGHT DOUBLE QUOTATION MARK instead.

In reply to Why does Encode::Repair only correctly fix one of these two tandem characters? by Jim

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