For the following rust code:

// cbindgen:ignore
// cbindgen:no-export
pub struct Foo;

// cbindgen:ignore
// cbindgen:no-export
impl Foo {
    // cbindgen:ignore
    // cbindgen:no-export
    pub const BAR: i64 = 42;
}

cbindgen still emits the following header code:

constexpr static const int64_t Foo_BAR = 42;

I haven't found any combination of annotations that can suppress it, even tho the docs suggest it should work?

For ignore:

You can manually ignore other stuff with the ignore annotation attribute

For no-export:

cbindgen will usually emit all items it finds, as instructed by the parse and export config sections. This annotation will make cbindgen skip this item from the output, while still being aware of it.