Generics missing when `allowlist_recursively` is false

[DexterHill0]

Take this example C++ code:

#pragma once

template <typename Type> class Vector2 {
  Type x;
  Type y;
};

template <typename Type> class Rectangle {
public:
  using Vector2Type = Vector2<Type>;

  Vector2Type p0;
  Vector2Type p1;
};

using Vector2f = Vector2<float>;
using Rectanglef = Rectangle<float>;

The bindings generated by bindgen when allowlist_recursively is false are:

#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct Vector2<Type> {
    pub _phantom_0: ::std::marker::PhantomData<::std::cell::UnsafeCell<Type>>,
    x: Type,
    y: Type,
}
#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct Rectangle<Type> {
    pub _phantom_0: ::std::marker::PhantomData<::std::cell::UnsafeCell<Type>>,
    pub p0: Rectangle_Vector2Type,
    pub p1: Rectangle_Vector2Type,
}
pub type Rectangle_Vector2Type = Vector2<Type>;
pub type Vector2f = Vector2<f32>;
pub type Rectanglef = Rectangle<f32>;

The generic type from Rectangle_Vector2Type has been dropped and the code is no longer valid. Setting allowlist_recursively to true will generate the correct code:

#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct Rectangle<Type> {
    pub _phantom_0: ::std::marker::PhantomData<::std::cell::UnsafeCell<Type>>,
    pub p0: Rectangle_Vector2Type<Type>,
    pub p1: Rectangle_Vector2Type<Type>,
}
pub type Rectangle_Vector2Type<Type> = Vector2<Type>;

Adding in more allowlist types, like Vector2Type or Rectangle::Vector2Type still does not prevent the generic from being generated correctly.

Bindgen version: 0.72.1

[DexterHill0]

Actually, although that example above is caused by allowlist_recursively, that doesn't seem to be the case all of the time. Something as simple as the following will fail to generate the generics correctly whether that setting is true or false.

template <typename T>
struct Inner {
    T x;
};

template <typename T>
struct Outer {
    typedef Inner<T> InnerT;
    InnerT items[4];
};