On Tue, 10 May 2016 14:27:20 -0700, sml...@gmail.com wrote: > It may have to do with their signature (as reported by the > `.signature` introspection method):
They're actually special-cased in the grammar[^1] based on their name: https://github.com/rakudo/rakudo/blob/4570238de7260b7360333aa216bb2b56949018fa/src/Perl6/Grammar.nqp#L3266-L3272 If it's possible to determine whether the name belongs to a non-core routine at the point where the error is emitted in the grammar, that'd be one way of avoiding the issue.