Should generators respect validations on schemas, and schema instances created from transformOrFail?

[beem812]

Current behavior:

1. Create a schema with a validation, then derive a generator for that schema.
   running that generator produces values that do not meet the schemas validation.

2. Create a schema via the .transformOrFail function, then derive a generator from that schema
   running the generator potentially produces no values, despite the condition for successful creation being something simple like strings longer than 5 characters

Potential solutions:

1. filter the generator over the validation to produce valid instances (It is dangerous to allow someone to create a filter that may never return a value, so this option seems bad)
2. Similar to one, for transformOrFail instances, keep creating until an instance is actually generated. Again dangerous if all cases fail.

[err0r500]

I've been surprised by the current behaviour, actually.
Don't know if it's possible but a solution might be to provide a generator for each validation and combine them.
It looks like it's what refined-scalacheck does (and it's not just filters)