capturing to lexical variable not handled

[p6rt]

Migrated from rt.perl.org#126243 (status was 'new')

Searchable as RT126243$

[p6rt]

From @FROGGS

my @​foo; say "abcxyd" ~~ m/@​foo=(.)/; say @​foo
rakudo-moar f52f0d​: OUTPUT«===SORRY!===␤QAST​::Block with cuid cuid_1_1443731047.48863 has not appeared␤»

I expect @​foo to contain the Match of the letter "a".