Can't use struct with reference to struct with lifetime as GAT about rust HOT 4 CLOSED

No problem, glad I could be of help!

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from rust.

If you have control over the definition of trait A, you can just update the assoc type Gat in both the trait def and the trait impl to type Gat<'a, 'b: 'a>... to make it pass:

trait A {
    type Gat<'a, 'b: 'a>;
}

struct R<'a>(&'a u32);
struct T<'a, 'b>(&'a R<'b>);

struct S;

impl A for S {
    type Gat<'a, 'b: 'a> = T<'a, 'b>;
}

from rust.

And if you can't change the definition of trait A (e.g., if it's part of a different crate or if you don't want to), well, then you simply can't assign T<'a, 'b> to it since they have different lifetime requirements.

from rust.

I see now, I had the requirements reversed, was trying to 'a: 'b instead of 'b: 'a. Sorry!

from rust.