Implement more traits for FRTs#155588
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Commit cb37ee2 ("make field representing types invariant over the base type") made the auto-trait impl work even if `T: !Send` or `T: !Sync` thus we can remove these explicit unsafe impls while FRTs still implement `Send` and `Sync`.
Using the reflection experiment, we can print the actual names of the field that an FRT is referring to. In case this breaks, there is an alternative implementation in the note comment.
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@rustbot label +F-field_projections |
| @@ -14,16 +15,50 @@ pub struct FieldRepresentingType<T: ?Sized, const VARIANT: u32, const FIELD: u32 | |||
| _phantom: PhantomData<fn(T) -> T>, | |||
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PhantomInvariant<T>? Or was this already discussed?
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Ah I didn't notice that that type was finally added! I'll change this the next time I make some changes here
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…ulacrum Implement more traits for FRTs From rust-lang#154927 (comment). FRTs now implement the following traits: `Sized + Freeze + RefUnwindSafe + Send + Sync + Unpin + UnsafeUnpin + UnwindSafe + Copy + Debug + Default + Eq + Hash + Ord`. Let me know if there is any trait missing. I also removed the explicit `Send` and `Sync` impls, since commit cb37ee2 ("make field representing types invariant over the base type") made the auto-trait impl work even if `T: !Send` or `T: !Sync`. Very happy to see unsafe impls get dropped :) Note that I used the reflection feature (cc @oli-obk) to print the actual field names in the debug implementation. I think this is a cool way to use it, but if it isn't ready for that, I'm happy to change it to the alternative implementation I gave in the note comment (it's essentially Mark's suggestion but printing `T`'s name instead of `Self`'s). Since this is a library change, I'll give this to Mark; feel free to also take a look/leave comments, Oli :) r? @Mark-Simulacrum
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…ulacrum Implement more traits for FRTs From rust-lang#154927 (comment). FRTs now implement the following traits: `Sized + Freeze + RefUnwindSafe + Send + Sync + Unpin + UnsafeUnpin + UnwindSafe + Copy + Debug + Default + Eq + Hash + Ord`. Let me know if there is any trait missing. I also removed the explicit `Send` and `Sync` impls, since commit cb37ee2 ("make field representing types invariant over the base type") made the auto-trait impl work even if `T: !Send` or `T: !Sync`. Very happy to see unsafe impls get dropped :) Note that I used the reflection feature (cc @oli-obk) to print the actual field names in the debug implementation. I think this is a cool way to use it, but if it isn't ready for that, I'm happy to change it to the alternative implementation I gave in the note comment (it's essentially Mark's suggestion but printing `T`'s name instead of `Self`'s). Since this is a library change, I'll give this to Mark; feel free to also take a look/leave comments, Oli :) r? @Mark-Simulacrum
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…uwer Rollup of 9 pull requests Successful merges: - #149624 (Fix requires_lto targets needing lto set in cargo) - #152443 (NVPTX: Drop support for old architectures and old ISAs) - #155317 (`std::io::Take`: Clarify & optimize `BorrowedBuf::set_init` usage.) - #155588 (Implement more traits for FRTs) - #155682 (Add boxing suggestions for `impl Trait` return type mismatches) - #155770 (Avoid misleading closure return type note) - #155818 (Convert attribute `FinalizeFn` to fn pointer) - #155829 (rustc_attr_parsing: use a `try {}` in `or_malformed`) - #155835 (couple of `crate_name` cleanups)
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Rollup of 12 pull requests Successful merges: - #149624 (Fix requires_lto targets needing lto set in cargo) - #155317 (`std::io::Take`: Clarify & optimize `BorrowedBuf::set_init` usage.) - #155579 (Make Rcs and Arcs use pointer comparison for unsized types) - #155588 (Implement more traits for FRTs) - #155708 (Fix heap overflow in slice::join caused by misbehaving Borrow) - #155778 (Avoid Vec allocation in TyCtxt::mk_place_elem) - #151014 (std: sys: process: uefi: Add program searching) - #155682 (Add boxing suggestions for `impl Trait` return type mismatches) - #155770 (Avoid misleading closure return type note) - #155818 (Convert attribute `FinalizeFn` to fn pointer) - #155829 (rustc_attr_parsing: use a `try {}` in `or_malformed`) - #155835 (couple of `crate_name` cleanups)
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Rollup merge of #155588 - BennoLossin:frt-traits, r=Mark-Simulacrum Implement more traits for FRTs From #154927 (comment). FRTs now implement the following traits: `Sized + Freeze + RefUnwindSafe + Send + Sync + Unpin + UnsafeUnpin + UnwindSafe + Copy + Debug + Default + Eq + Hash + Ord`. Let me know if there is any trait missing. I also removed the explicit `Send` and `Sync` impls, since commit cb37ee2 ("make field representing types invariant over the base type") made the auto-trait impl work even if `T: !Send` or `T: !Sync`. Very happy to see unsafe impls get dropped :) Note that I used the reflection feature (cc @oli-obk) to print the actual field names in the debug implementation. I think this is a cool way to use it, but if it isn't ready for that, I'm happy to change it to the alternative implementation I gave in the note comment (it's essentially Mark's suggestion but printing `T`'s name instead of `Self`'s). Since this is a library change, I'll give this to Mark; feel free to also take a look/leave comments, Oli :) r? @Mark-Simulacrum
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From #154927 (comment).
FRTs now implement the following traits:
Sized + Freeze + RefUnwindSafe + Send + Sync + Unpin + UnsafeUnpin + UnwindSafe + Copy + Debug + Default + Eq + Hash + Ord.Let me know if there is any trait missing.
I also removed the explicit
SendandSyncimpls, since commit cb37ee2 ("make field representing types invariant over the base type") made the auto-trait impl work even ifT: !SendorT: !Sync. Very happy to see unsafe impls get dropped :)Note that I used the reflection feature (cc @oli-obk) to print the actual field names in the debug implementation. I think this is a cool way to use it, but if it isn't ready for that, I'm happy to change it to the alternative implementation I gave in the note comment (it's essentially Mark's suggestion but printing
T's name instead ofSelf's).Since this is a library change, I'll give this to Mark; feel free to also take a look/leave comments, Oli :)
r? @Mark-Simulacrum