I'd prefer the naming to_unsafe, despite it not being entirely correct. We've discussed that booleans don't have an ordering before so naturally I think that extends to we shouldn't encourage people to see booleans as numbers.

I think that @woodruffw his to_i is more clear to understand. The to_unsafe is a keyword is better left to actions that really are unsafe.

I agree with @RX14 -- to_i might be more correct, but treating a boolean as an integer anywhere in (pure) Crystal is probably a code smell. to_unsafe expresses that more explicitly, even if it's a perfectly safe operation from the compiler/runtime's perspective.

Has the added benefit of allowing you to pass boolean variables into functions without conversion - the to_unsafe is automatic.

probably better let compiler accept boolean in c binding

There's nothing unsafe from going from Bool to Int32. I agree with @larubujo here, bools should be allowed in C bindings (I tried to implement that once but failed, but I'm sure it can be done).

@asterite I agree there's noting unsafe about going Bool to Int32 but I think it's the best thing to do here.

Also implementing Bool in C bindings is weird to me, as bool isn't a datatype in C, it's only implemented as an integer.