Yath cannot be run through carmel exec

[bbrtj]

If I set App::Yath as a dependency in my project and try to test it with carmel exec yath, I get the following error:

encountered object 'Carmel::Runtime::FastINC=HASH(0x38b48f6f8bb8)', but allow_blessed, allow_stringify or TO_JSON/FREEZE method missing at /home/devenv/.carmel/5.40.0-amd64-freebsd/builds/Test2-Harness-1.000155/blib/lib/Test2/Harness/Util/JSON.pm line 58.

Not sure which feature of yath causes that, I've tried disabling some logging with command line flags but that didn't help. Seems like Carmel::Setup puts some objects into the @INC and Yath can't encode them with JSON. Hope it's fixable.

Related discussion: miyagawa/Carmel#108