Since this was all about .sprintf being called with only one argument but two directives (also cmp. #106594) and since the Null PMC access error is gone, this ticket could be closed IMHO.
On the other hand the error from sprintf doesn't look very awesome in the given case: $ perl6-m -e 'sprintf("%d %d", 3);' No such method 'item' for invocant of type 'NQPMu' in method message at src/gen/m-CORE.setting:13340 $ perl6-p -e 'sprintf("%d %d", 3);' Type check failed in binding $expected; expected 'Any' but got 'Mu' in block at gen/parrot/CORE.setting:963 in method BUILDALL at gen/parrot/CORE.setting:946 in method bless at gen/parrot/CORE.setting:935 in method new at gen/parrot/CORE.setting:920 in method new at gen/parrot/CORE.setting:918 $ perl6-j -e 'sprintf("%d %d", 3);' Type check failed in binding $expected; expected 'Any' but got 'Mu' in block at gen/jvm/CORE.setting:949 in method BUILDALL at gen/jvm/CORE.setting:932 in method bless at gen/jvm/CORE.setting:921 in method new at gen/jvm/CORE.setting:905 The error message looks better for strings (AFAIU that was fixed for ticket #106594): $ /perl6-m -e 'sprintf("%s %s", "foo");' Too many directives: found 2, but only 1 arguments after the format string So maybe instead of closing this ticket we should change the subject of this ticket to 'LTA error message when .sprintf is called with more directives than arguments (numeric)'?