[kaan650]

In strict mode the error handler for effects passes the error to string.find(), so an error that isn't a string makes the handler itself error and the original error is lost:

vide.strict = true

effect(function()
    error({ code = 1 })
end)
-- effect error stacktrace
-- error in error handling

This converts the error with tostring() first, like effect_traceback() does in non-strict mode.