Current failure mode (branch 'glr', perl6 version 2015.07.1-682-g57b7ebc built on MoarVM version 2015.07-108-g7e9f29e):
$ perl6-m -e 'sub foo ($bar :D) { 1; }' ===SORRY!=== Cannot invoke this object (REPR: P6opaque, cs = 0) $ perl6-m --ll-exception -e 'sub foo ($bar :D) { 1; }' Cannot invoke this object (REPR: P6opaque, cs = 0) at src/Perl6/World.nqp:1640 (./blib/Perl6/World.moarvm:create_signature_and_params:551) from src/Perl6/Grammar.nqp:2489 (./blib/Perl6/Grammar.moarvm:routine_def:946) from <unknown>:1 (./blib/Perl6/Grammar.moarvm:routine_declarator:sym<sub>:147) from gen/moar/stage2/QRegex.nqp:1350 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/QRegex.moarvm:!protoregex:109) from <unknown>:1 (./blib/Perl6/Grammar.moarvm:routine_declarator:10) from <unknown>:1 (./blib/Perl6/Grammar.moarvm:term:sym<routine_declarator>:57) from gen/moar/stage2/QRegex.nqp:1350 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/QRegex.moarvm:!protoregex:109) from <unknown>:1 (./blib/Perl6/Grammar.moarvm:term:10) from src/Perl6/Grammar.nqp:3615 (./blib/Perl6/Grammar.moarvm:termish:403) from gen/moar/stage2/NQPHLL.nqp:678 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:EXPR:74) from src/Perl6/Grammar.nqp:3649 (./blib/Perl6/Grammar.moarvm:EXPR:24) from src/Perl6/Grammar.nqp:1191 (./blib/Perl6/Grammar.moarvm:statement:395) from src/Perl6/Grammar.nqp:1126 (./blib/Perl6/Grammar.moarvm:statementlist:280) from gen/moar/stage2/NQPHLL.nqp:895 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:LANG:146) from src/Perl6/Grammar.nqp:1516 (./blib/Perl6/Grammar.moarvm:FOREIGN_LANG:67) from src/Perl6/Grammar.nqp:1103 (./blib/Perl6/Grammar.moarvm:comp_unit:1025) from src/Perl6/Grammar.nqp:402 (./blib/Perl6/Grammar.moarvm:TOP:528) from gen/moar/stage2/QRegex.nqp:1997 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/QRegex.moarvm:parse:44) from gen/moar/stage2/NQPHLL.nqp:1580 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:parse:80) from gen/moar/stage2/NQPHLL.nqp:1536 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:compile:202) from gen/moar/stage2/NQPHLL.nqp:1272 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:eval:62) from gen/moar/stage2/NQPHLL.nqp:1379 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm::35) from gen/moar/stage2/NQPHLL.nqp:1376 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:command_eval:155) from src/Perl6/Compiler.nqp:59 (./blib/Perl6/Compiler.moarvm:command_eval:93) from gen/moar/stage2/NQPHLL.nqp:1360 (/home/christian/bin/rakudo.moar-glr/share/nqp/lib/NQPHLL.moarvm:command_line:114) from src/gen/m-main.nqp:39 (/usr/home/christian/perl6/perl6-roast-data/rakudo.moar-glr/perl6.moarvm:MAIN:18) from src/gen/m-main.nqp:35 (/usr/home/christian/perl6/perl6-roast-data/rakudo.moar-glr/perl6.moarvm:<mainline>:197) from <unknown>:1 (/usr/home/christian/perl6/perl6-roast-data/rakudo.moar-glr/perl6.moarvm:<main>:8) from <unknown>:1 (/usr/home/christian/perl6/perl6-roast-data/rakudo.moar-glr/perl6.moarvm:<entry>:9)