Fixed in https://github.com/rakudo/rakudo/commit/6ef4cdf543
Tests added in https://github.com/perl6/roast/commit/925cf4bd8b
On Tue Sep 27 11:39:00 2016, c...@zoffix.com wrote:
> # I have the fix; filing for records
>
> The .subst/.subst-mutate methods slurp several of their options into a
> hash and then pass those
> along to Str.match call. The logic that handles the result of that
> call, however, does not
> pay attention to Failures. Specifically, failures resulting from
> incorrect values provided for
> the named arguments that get passed to .match:
>
> m: say 'foo'.subst: /\w/, '', :x{2}
> rakudo-moar 222d16: OUTPUT«foo»
> m: say 'foo'.subst: /\w/, '', :th(2.5)
> rakudo-moar 222d16: OUTPUT«foo»
> m: say ($ = 'foo').subst-mutate: /\w/, '', :th(2.5)
> rakudo-moar 222d16: OUTPUT«Nil»
>
> Thus, the user never receives any indication they're using the wrong
> arguments and the code behaves as the match simply fails.
