Coherence should allow fundamental types to impl traits when they are local #65738
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Heh, good catch @ohadravid -- I'm torn about the test. You're right that we don't need one in some sense but I think if you don't mind adding one it would help us to prevent similar oversights in the future. |
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@nikomatsakis I added two tests which should prevent a regression. BTW I can also open the stabilization PR for Original failures are: and |
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@bors r+ |
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📌 Commit 8f988bd has been approved by |
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@ohadravid thanks! And yes, a stabilization PR would be great! Please explicitly add |
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…low-fundamental-local, r=nikomatsakis Coherence should allow fundamental types to impl traits when they are local After rust-lang#64414, `impl<T> Remote for Box<T> { }` is disallowed, but it is also disallowed in liballoc, where `Box` is a local type! Enabling `#![feature(re_rebalance_coherence)]` in `liballoc` results in: ``` error[E0210]: type parameter `F` must be used as the type parameter for some local type (e.g., `MyStruct<F>`) --> src\liballoc\boxed.rs:1098:1 | 1098 | impl<F: ?Sized + Future + Unpin> Future for Box<F> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `F` must be used as the type parameter for some local type ``` This PR relaxes `uncover_fundamental_ty` to skip local fundamental types. I didn't add a test since `liballoc` already fails to compile, but I can add one if needed. r? @nikomatsakis cc rust-lang#63599
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…low-fundamental-local, r=nikomatsakis Coherence should allow fundamental types to impl traits when they are local After rust-lang#64414, `impl<T> Remote for Box<T> { }` is disallowed, but it is also disallowed in liballoc, where `Box` is a local type! Enabling `#![feature(re_rebalance_coherence)]` in `liballoc` results in: ``` error[E0210]: type parameter `F` must be used as the type parameter for some local type (e.g., `MyStruct<F>`) --> src\liballoc\boxed.rs:1098:1 | 1098 | impl<F: ?Sized + Future + Unpin> Future for Box<F> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `F` must be used as the type parameter for some local type ``` This PR relaxes `uncover_fundamental_ty` to skip local fundamental types. I didn't add a test since `liballoc` already fails to compile, but I can add one if needed. r? @nikomatsakis cc rust-lang#63599
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…low-fundamental-local, r=nikomatsakis Coherence should allow fundamental types to impl traits when they are local After rust-lang#64414, `impl<T> Remote for Box<T> { }` is disallowed, but it is also disallowed in liballoc, where `Box` is a local type! Enabling `#![feature(re_rebalance_coherence)]` in `liballoc` results in: ``` error[E0210]: type parameter `F` must be used as the type parameter for some local type (e.g., `MyStruct<F>`) --> src\liballoc\boxed.rs:1098:1 | 1098 | impl<F: ?Sized + Future + Unpin> Future for Box<F> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type parameter `F` must be used as the type parameter for some local type ``` This PR relaxes `uncover_fundamental_ty` to skip local fundamental types. I didn't add a test since `liballoc` already fails to compile, but I can add one if needed. r? @nikomatsakis cc rust-lang#63599
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Rollup of 6 pull requests Successful merges: - #65566 (Use heuristics to suggest assignment) - #65738 (Coherence should allow fundamental types to impl traits when they are local) - #65777 (Don't ICE for completely unexpandable `impl Trait` types) - #65834 (Remove lint callback from driver) - #65839 (Clean up `check_consts` now that new promotion pass is implemented) - #65855 (Add long error explaination for E0666) Failed merges: r? @ghost
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☔ The latest upstream changes (presumably #65869) made this pull request unmergeable. Please resolve the merge conflicts. |
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After #64414,
impl<T> Remote for Box<T> { }is disallowed, but it is also disallowed in liballoc, whereBoxis a local type!Enabling
#![feature(re_rebalance_coherence)]inliballocresults in:This PR relaxes
uncover_fundamental_tyto skip local fundamental types.I didn't add a test since
liballocalready fails to compile, but I can add one if needed.r? @nikomatsakis
cc #63599