That's the problem though, right? If it's pointed out we all agree the "do not keep credentials alive" is a property that should hold and we can leverage whatever the environment offers to help preserve it. I fully agree modern languages have amazing support for this, but in C you can still run tests. Let's just say I don't think the language's inability to express logic of this kind held all those involved back from testing for it. I personally find "we just didn't think of it" much more likely.
That said, I am not a fan of C and recommend leveraging whatever fantastic modern tooling is available to you.
struct Builder<const A: bool, const B: bool> {
a: Option<u32>,
b: Option<u32>,
}
struct Val {
a: u32,
b: u32,
}
impl<const B: bool> Builder<false, B> {
fn set_a(self, a: u32) -> Builder<true, B> {
Builder {
a: Some(a),
b: self.b,
}
}
}
impl<const A: bool> Builder<A, false> {
fn set_b(self, b: u32) -> Builder<A, true> {
Builder {
a: self.a,
b: Some(b),
}
}
}
impl Builder<true, true> {
fn build(self) -> Val {
Val {
a: self.a.unwrap(),
b: self.b.unwrap(),
}
}
}