False positive "Foo depends on itself"

const A = struct {
    b: B,
};

const B = fn(A) void;

pub fn main() void {
    //var a: A = undefined; // uncomment this line for: segfault
    //var b: B = undefined; // uncomment this line for: error: 'B' depends on itself
}

const B = fn(*A) void; // changing the definition of B slightly, now the below compiles without a segfault or compile errors
pub fn main() void {
    var a: A = undefined;
}

This code should compile. In fact B looks a lot like a virtual function taking a 'this' by value or by pointer. translate-c on uv.h (libuv) gives the error "uv_close_cb depends on itself" which is how I came across this bug.

[andrewrk]

Might be related to #624