I'm confused -- in what sense doesn't it capture properly?

  DB<1> $x = qr/(\d\s+foo)/;

  DB<2> $y = 'alpha beta 1 foo gamma delta 2 foo epsilon omega';

  DB<3> @z = $y =~ /$x[^\r\n]*$x/;

  DB<4> x @z
0  '1 foo'
1  '2 foo'
  DB<5>
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However, I can vaguely see problems getting the capturing desired, if it isn't conveniently what happens when trying to scale.