`checked` does nothing without `#[stabby::export]`

[matejcik]

the following code compiles with no errors:

#[stabby::stabby(checked)]
pub trait Trait {
    extern "C" fn func(&self, opt: Option<u8>) -> u8;
}

impl Trait for u8 {
    extern "C" fn func(&self, opt: Option<u8>) -> u8 {
        opt.unwrap_or(0)
    }
}

fn main() {
    let mut value = 42;
    let dynptr = <stabby::dynptr!(&'_ mut dyn Trait)>::from(&mut value);
    dynptr.func(Some(42));
}

far as I and my AI friends were able to determine, all the bounds for IStable are generated correctly, but nothing nowhere asserts the ABI stability

i tried to figure out an automated insertion point for assert_stable. and it seems to me that it can't really be done if there are any generic types involved, because you need a concrete type for assert_stable, correct? still, it may be nice to insert it if no generics are present.
in my usecase there's a root API trait that can't be generic, so that would trigger a stability check for the whole API-accessible tree.

[p-avital]

Hi,

stabby(checked) should be asserting that all types in the signatures are IStable, which would be the case if that Option is the one defined by stabby.

It would be a bug if it compiles with a standard core::option::Option as that one's layout isn't guaranteed for types with more than a single niche :/

Fun story, this checked used to be inverted (you could opt-out, but opt-in was the default), but I had to invert it because it could cause infinite loops in the proof engine if the signatures mentioned the type itself :)

[matejcik]

It would be a bug if it compiles with a standard core::option::Option as that one's layout isn't guaranteed for types with more than a single niche :/

that is the case. this is core::option::Option, and i am getting a failure if i manually insert assert_stable::<dyn Trait>()

i can do you one better:

#[derive(Debug)]
pub enum Hello {
    World,
}

#[stabby::stabby(checked)]
pub trait Trait {
    extern "C" fn func(&self, opt: Hello);
}

funnily enough, if I use stabby::abi::Option<Hello>, i get an error immediately because stabby's Option apparently has the bound

[matejcik]

manually insert assert_stable::<dyn Trait>()

sorry, the right spelling is apparently assert_stable::<stabby::dynptr!(&'_ dyn Trait)>()

in some cases i'm even getting compiler warnings about types not being FFI-stable, while stabby(checked) indicates no problems