Ability to assert over shared attributes

I’m trying to do this:

shared class Foo(X val){
   shared Y y;
   assert(exists y = val.possiblyY());
}

And well, it’s not allowed, so I have to do this stupid code:

shared class Foo(X val){
   assert(exists y_ = val.possiblyY());
   shared Y y = y_;
}

Is it something we could allow or is there another way to do this?

[FroMage]

Or a stef expression:

shared Y y = stef(exists x = f()) x;

Where stef has the same powers as assert but with a cooler name. Ties in well with my other issue about assert in comprehensions…

[ncorai]

Bumped into this issue today