Make some Option, Result methods unstably const #82130
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These functions implicitly depend on |
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Triage: @ecstatic-morse seems busy recently, r? @RalfJung could you take a look? |
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This LGTM; Cc @rust-lang/wg-const-eval |
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With regard to the const-hack label, should we really consider this a hack? I just quickly checked on godbolt, and it looks like the new implementation actually optimizes slightly better at lower opt levels. Not a huge deal either way, but I figure we may as well take a minuscule performance gain where we can. The implementation is straightforward in either situation. |
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We typically use that label when code gets changed to be const-compatible. I don't feel competent to evaluate whether the old or the new implementation is better, but I can imagine that avoiding higher-order functions helps. @oli-obk what do you think? |
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I actually prefer the new implementation since imo it's more readable, even if the old version is more compact |
All right, I tend to agree so I removed the label. |
The following functions are now unstably const: - Option::transpose - Option::flatten - Result::transpose
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@bors r+ rollup |
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📌 Commit 79c2b75 has been approved by |
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…Jung Make some Option, Result methods unstably const The following methods are now unstably const: - Option::transpose - Option::flatten - Result::flatten While some methods for could likely be made `const` in the future, nearly all of them require something to be dropped at compile-time, which isn't currently supported. The functions listed above should have a trivial path to stabilization.
Rollup of 13 pull requests Successful merges: - rust-lang#77916 (Change built-in kernel targets to be os = none throughout) - rust-lang#82130 (Make some Option, Result methods unstably const) - rust-lang#82292 (Prevent specialized ZipImpl from calling `__iterator_get_unchecked` twice with the same index) - rust-lang#82402 (Remove RefCell around `module_trait_cache`) - rust-lang#82592 (Improve transmute docs with further clarifications) - rust-lang#82651 (Cleanup rustdoc warnings) - rust-lang#82720 (Fix diagnostic suggests adding type `[type error]`) - rust-lang#82751 (improve offset_from docs) - rust-lang#82793 (Move some tests to more suitable subdirs) - rust-lang#82803 (rustdoc: Add an unstable option to print all unversioned files) - rust-lang#82808 (Sync rustc_codegen_cranelift) - rust-lang#82822 (Fix typo) - rust-lang#82837 (tweak MaybeUninit docs) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
The following methods are now unstably const:
While some methods for could likely be made
constin the future, nearly all of them require something to be dropped at compile-time, which isn't currently supported. The functions listed above should have a trivial path to stabilization.