Please take a look at the following code: 
$a = qr{\QHello# World\E}x;
$b = qr{Hello\#\ World}x;

$test = "Hello# World";

$test =~ $a && print "\$a matches \$test\n";
$test =~ $b && print "\$b matches \$test\n";

print "\$a = $a\n\$b = $b\n";

[download]
Output is following: 
$b matches $test
$a = (?x-ism:Hello\#\ World\\E)
$b = (?x-ism:Hello\#\ World)
Why regular expressions $a and $b are not the same?

In perlre said that \Q and \E should quote white space and "#" character. It actually quotes the "#" character, but it quotes absolutely everything (even \E) after the "#" character.

Thank you very much for your attention!

In reply to Weird quoting with /x modifier by ykar

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