Expose the Freeze trait again (unstably) and forbid implementing it manually #121840
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Some changes occurred in compiler/rustc_codegen_gcc Some changes occurred in compiler/rustc_codegen_cranelift cc @bjorn3 |
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Looks good to me but I guess this is r? libs-api as the original PR. |
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dtolnay
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Nice. :) I also have needed this — compiling the test case with T: Freeze removed, I recognize this error message:
error[E0492]: constants cannot refer to interior mutable data
--> tests/ui/associated-consts/freeze.rs:9:35
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9 | const VALUE_REF: &'static T = &Self::VALUE;
| ^^^^^^^^^^^^ this borrow of an interior mutable value may end up in the final value
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@bors r+ |
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Expose the Freeze trait again (unstably) and forbid implementing it manually non-emoji version of rust-lang#121501 cc rust-lang#60715 This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue. It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: google/zerocopy#941 cc `@RalfJung` T-lang signed off on reexposing this unstably: rust-lang#121501 (comment)
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Expose the Freeze trait again (unstably) and forbid implementing it manually non-emoji version of rust-lang#121501 cc rust-lang#60715 This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue. It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: google/zerocopy#941 cc ``@RalfJung`` T-lang signed off on reexposing this unstably: rust-lang#121501 (comment)
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Rollup of 8 pull requests Successful merges: - rust-lang#121148 (Add slice::try_range) - rust-lang#121573 (unix_sigpipe: Add test for SIGPIPE disposition in child processes) - rust-lang#121633 (Win10: Use `GetSystemTimePreciseAsFileTime` directly) - rust-lang#121840 (Expose the Freeze trait again (unstably) and forbid implementing it manually) - rust-lang#121907 (skip sanity check for non-host targets in `check` builds) - rust-lang#122002 (std::threads: revisit stack address calculation on netbsd.) - rust-lang#122108 (Add `target.*.runner` configuration for targets) - rust-lang#122298 (RawVec::into_box: avoid unnecessary intermediate reference) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 9 pull requests Successful merges: - rust-lang#121148 (Add slice::try_range) - rust-lang#121633 (Win10: Use `GetSystemTimePreciseAsFileTime` directly) - rust-lang#121840 (Expose the Freeze trait again (unstably) and forbid implementing it manually) - rust-lang#121907 (skip sanity check for non-host targets in `check` builds) - rust-lang#122002 (std::threads: revisit stack address calculation on netbsd.) - rust-lang#122108 (Add `target.*.runner` configuration for targets) - rust-lang#122298 (RawVec::into_box: avoid unnecessary intermediate reference) - rust-lang#122315 (Allow multiple `impl Into<{D,Subd}iagMessage>` parameters in a function.) - rust-lang#122326 (Optimize `process_heap_alloc`) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#121840 - oli-obk:freeze, r=dtolnay Expose the Freeze trait again (unstably) and forbid implementing it manually non-emoji version of rust-lang#121501 cc rust-lang#60715 This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue. It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: google/zerocopy#941 cc ```@RalfJung``` T-lang signed off on reexposing this unstably: rust-lang#121501 (comment)
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Mar 12, 2024
Nightly now exposes `core::marker::Freeze`. rust-lang/rust#121840
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Nightly now exposes `core::marker::Freeze`. rust-lang/rust#121840
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Expose the Freeze trait again (unstably) and forbid implementing it manually non-emoji version of rust-lang#121501 cc rust-lang#60715 This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue. It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: google/zerocopy#941 cc ```@RalfJung``` T-lang signed off on reexposing this unstably: rust-lang#121501 (comment)
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Expose the Freeze trait again (unstably) and forbid implementing it manually non-emoji version of rust-lang#121501 cc rust-lang#60715 This trait is useful for generic constants (associated consts of generic traits). See the test (`tests/ui/associated-consts/freeze.rs`) added in this PR for a usage example. The builtin `Freeze` trait is the only way to do it, users cannot work around this issue. It's also a useful trait for building some very specific abstrations, as shown by the usage by the `zerocopy` crate: google/zerocopy#941 cc ```@RalfJung``` T-lang signed off on reexposing this unstably: rust-lang#121501 (comment)
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non-emoji version of #121501
cc #60715
This trait is useful for generic constants (associated consts of generic traits). See the test (
tests/ui/associated-consts/freeze.rs) added in this PR for a usage example. The builtinFreezetrait is the only way to do it, users cannot work around this issue.It's also a useful trait for building some very specific abstrations, as shown by the usage by the
zerocopycrate: google/zerocopy#941cc @RalfJung
T-lang signed off on reexposing this unstably: #121501 (comment)