the thing where rustc does the thing

validate.rs

struct Valid<T>(T);

trait Validate: Sized {
    fn validate(self) -> Result<Valid<Self>, Error>;
}

struct Error {
    msg: String,
}

impl<T> TryFrom<T> for Valid<T>
where
    T: Validate,
{
    type Error = Error;

    fn try_from(t: T) -> Result<Valid<T>, Error> {
        t.validate()
    }
}