Stop creating references unnecessarily to compare pointers by-address #31
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The test `common::deque::basics` contains several lines that look like this:
```
assert!(std::ptr::eq(head_d, unsafe { node1_ptr.as_ref() }));
```
What is happening is that we assert that `head_c`, a reference, is equal
by-address to `node1_ptr`, a `NonNull<_>`. However, the way we do this
is by creating a reference, instead of using `as_ptr`.
The current way has several downsides:
* It requires an `unsafe` block. Comparing pointer addresses is safe so
this should be unnecessary.
* **It is unsound**, at least under Tree Borrows rules.
The references created there violate the uniqueness of references/Boxes
created internally in the `Deque`, which trips the `Deque` later when
it tries to use these internally-held references.
* It is unnecessary -- comparing the result of `as_ptr` works just the same,
maybe even faster due to less intermediary methods.
As such, the test should be updated to only use `as_ptr`. When done, it
actually makes the tests pass under Tree Borrows.
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tatsuya6502
added a commit
that referenced
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Sep 8, 2024
Apply the fix in #31 to the `v0.10.x` branch
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The test
common::deque::basicscontains several lines that look like this:What is happening is that we assert that
head_c, a reference, is equal by-address tonode1_ptr, aNonNull<_>. However, the way we do this is by creating a reference, instead of usingas_ptr.The current way has several downsides:
unsafeblock. Comparing pointer addresses is safe so this should be unnecessary.Deque, which trips theDequelater when it tries to use these internally-held references.as_ptrworks just the same, maybe even faster due to less intermediary methods.As such, the test should be updated to only use
as_ptr. When done, it actually makes the tests pass under Tree Borrows.See also moka-rs/moka#452