rust-pyo3: simplified API to get core Index references...
rust-pyo3: simplified API to get core Index references
Given the amount of conversion and arcane internal detail, it
is easier for the caller and makes a better separation of concerns
to just introduce a new unsafe helper. It is actually possible that
it would be safe, and we can decide about that later.
Actually the reason given in the `cpython` crate for unsafety of the
`try_borrow()` method is the following:
```
// try_borrow() and try_borrow_mut() are unsafe because self.data may
// have a function returning the inner &'static reference.
// If T is &'static U, its lifetime can be easily coerced to &'a U, but
// how could we do that for Whatever<'static> in general?
```
Given that we coerce the Index reference to the GIL lifetime and that
it is unlikely that the inner data would contain a function returning the
a `'static` reference, it is possible that it is actually even safe.
