This is another instance of the problem that a pair of curlies can stand for an anonymous subroutine or a hash reference. You can disambiguate with a semicolon in the block: 

my %y = map {; "prefix_$_" => 1 } qw(a b c);

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It's more of a design limitation than a bug in perl or in you :-)

Perl 6 - second systems done right

In reply to Re: map problem by moritz
in thread map problem by morgon

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