Just a precedence issue. Add parens. 
my %new2 =
hmap { $_[1]{nick} =~ /rbush|fred/
          ? ( $_[0] => { hmap { $_[0], $_[1] } %{$_[1]} } )
          : ()
     } %$h;

[download]
my $new2 =
hmap { $_[1]{nick} =~ /rbush|fred/
          ? ( $_[0] => hmap { $_[0], $_[1] } $_[1] )
          : ()
     } $h;

[download]

In reply to Re^3: hmap revisited by ikegami
in thread hmap revisited by zerohero

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