From @zoffixznet

The culprit is this line that make an nqp​::hash out of Pairs, but I guess we don't yet have object nqp hashes? https://github.com/rakudo/rakudo/blob/c82b72a/src/core/List.pm#L886

  <Zoffix___> m​: (class {} => 42,).Capture
  <evalable6> Zoffix___, rakudo-moar c82b72ae3​: OUTPUT​: «(exit code 1) Cannot unbox a type object (<anon|50703168>) to a str.␤ in block <unit> at /tmp/Qa6ci_ikcF line 1␤»
  <Zoffix___> m​: (<a b> => 42,).Capture
  <evalable6> Zoffix___, rakudo-moar c82b72ae3​: OUTPUT​: «(exit code 1) This type cannot unbox to a native string​: P6opaque, List␤ in block <unit> at /tmp/okIydC1bSK line 1␤»

From @zoffixznet

On Tue, 23 May 2017 15​:59​:43 -0700, cpan@​zoffix.com wrote​:

The culprit is this line that make an nqp​::hash out of Pairs, but I
guess we don't yet have object nqp hashes?
https://github.com/rakudo/rakudo/blob/c82b72a/src/core/List.pm#L886

<Zoffix___> m​: (class {} => 42,).Capture
<evalable6> Zoffix___, rakudo-moar c82b72ae3​: OUTPUT​: «(exit code 1)
Cannot unbox a type object (<anon|50703168>) to a str.␤ in block
<unit> at /tmp/Qa6ci_ikcF line 1␤»
<Zoffix___> m​: (<a b> => 42,).Capture
<evalable6> Zoffix___, rakudo-moar c82b72ae3​: OUTPUT​: «(exit code 1)
This type cannot unbox to a native string​: P6opaque, List␤ in block
<unit> at /tmp/okIydC1bSK line 1␤»

Thank you for the report. This is now fixed.

Fix​: rakudo/rakudo@5b25836f21
Tests​: Raku/roast@ae935c92eb

@zoffixznet - Status changed from 'new' to 'resolved'