bors-servo
2ba1ea2405
BUG: Add test showing how downcasting to CFArray is unsound
This PR is not intended to me merged directly. It adds a test that causes undefined behavior without using `unsafe {}`. So it's more to show the problem and discuss a solution.
The problem here is that if you have a `CFArray<X>` you can cast it up to a `CFType` and then down to a `CFArray<Y>` for any `Y: TCFType`. It never checks that the elements in the array are of type `Y` or not. At this point `CFArray::iter` will happily give out `&Y` references, while in fact the pointers backing those objects are pointing to `XRef` instances. So doing anything with the `&Y` will likely cause invalid memory access.
How do we solve this?
Ping @jrmuizel
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core-foundation-rs
Compatibility
By default it targets macOS 10.7.
To enable features added in macOS 10.8, set Cargo feature mac_os_10_8_features. To have both 10.8 features and 10.7 compatibility, also set mac_os_10_7_support. Setting both requires weak linkage, which is is a nighty-only feature as of Rust 1.19.