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Check for isize overflow before Layout construction #294

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Merged
merged 2 commits into from
Oct 4, 2022
Merged

Check for isize overflow before Layout construction #294

merged 2 commits into from
Oct 4, 2022

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dtolnay
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@dtolnay dtolnay commented Oct 4, 2022

See rust-lang/rust#101899. rust-lang/rust#95295, which looks like it is going to be un-reverted, makes the following change to the error condition of Layout::from_size_align and thus the safety requirement of Layout::from_size_align_unchecked:

     /// * `size`, when rounded up to the nearest multiple of `align`,
-    ///    must not overflow (i.e., the rounded value must be less than
-    ///    or equal to `usize::MAX`).
+    ///    must not overflow isize (i.e., the rounded value must be
+    ///    less than or equal to `isize::MAX`).

dtolnay added 2 commits October 4, 2022 13:54
@dtolnay
Check for isize overflow before Layout construction
02a9ca8
@dtolnay
Restore compatibility with rustc older than 1.43
6b0af67 
    error[E0599]: no associated item named `MAX` found for type `isize` in the current scope
       --> src/identifier.rs:106:37
        |
    106 |         debug_assert!(len <= isize::MAX as usize);
        |                                     ^^^ associated item not found in `isize`
        |
    help: you are looking for the module in `std`, not the primitive type
        |
    106 |         debug_assert!(len <= std::isize::MAX as usize);
        |                              ^^^^^^^^^^^^^^^

    error[E0599]: no associated item named `MAX` found for type `usize` in the current scope
       --> src/identifier.rs:132:44
        |
    132 |                     let max_alloc = usize::MAX / 2 - align;
        |                                            ^^^ associated item not found in `usize`
        |
    help: you are looking for the module in `std`, not the primitive type
        |
    132 |                     let max_alloc = std::usize::MAX / 2 - align;
        |                                     ^^^^^^^^^^^^^^^
@dtolnay dtolnay merged commit 626d7c7 into master Oct 4, 2022
@dtolnay dtolnay deleted the isize branch October 4, 2022 21:02
@joshlf joshlf mentioned this pull request Oct 15, 2022
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