dont randomly use `_` to print out const generic arguments
const generics seem to get printed out as `_` for no reason a lot of the time, as someone who spends a lot of time with const generics this has gotten ✨ very annoying ✨. Latest example would be #106423 where the ICE messaged formatted a `ty::Const` containing no infer vars, as `_`.
For some reason printing of the const argument on arrays was custom instead of using the existing logic for printing `ty::Const`. Additionally the existing logic for printing `ty::Const` would print out `_` for anon consts that are in a separate crate leading to weird diagnostics (see second commit). There ought to be less cases of consts randomly getting printed as `_` hiding valuable info now.
Add 'static lifetime suggestion when GAT implied 'static requirement from HRTB
Fix for issue #105507
The problem:
When generic associated types (GATs) are from higher-ranked trait bounds (HRTB), they are implied 'static requirement (see
[Implied 'static requirement from higher-ranked trait bounds](https://blog.rust-lang.org/2022/10/28/gats-stabilization.html#implied-static-requirement-from-higher-ranked-trait-bounds) for more details). If the user did not explicitly specify the `'static` lifetime when using the GAT, the current error message will only point out the type `does not live long enough` where the type is used, but not where the GAT is specified and how to fix the problem.
The solution:
Add notes at the span where the problematic GATs are specified and suggestions of how to fix the problem by adding `'static` lifetime at the right spans.
Improve Markdown styling in README
Update Readme to use consistent line lengths. Also update some formatting and links. (Followup to https://github.com/rust-lang/rust/pull/105553).
r? ``@workingjubilee``
9 commits in 1cd6d3803dfb0b342272862a8590f5dfc9f72573..a5d47a72595dd6fbe7d4e4f6ec20dc5fe724edd1
2023-01-12 18:40:36 +0000 to 2023-01-16 18:51:50 +0000
- Add network container tests (rust-lang/cargo#11583)
- Show progress of crates.io index update even `net.git-fetch-with-cli` option enabled (rust-lang/cargo#11579)
- `cargo metadata` supports artifact dependencies (rust-lang/cargo#11550)
- fix(docs): add required "inherits" option to example profile (rust-lang/cargo#11504)
- add documentation that SSH markers aren't supported (rust-lang/cargo#11586)
- Fix typo (rust-lang/cargo#11585)
- Enable source_config_env test on Windows (rust-lang/cargo#11582)
- Support `codegen-backend` and `rustflags` in profiles in config file (rust-lang/cargo#11562)
- ci: reflect to clap updates (rust-lang/cargo#11578)
vec::Splice can invalidate the slice::Iter inside vec::Drain.
So we replace them with dangling pointers which, unlike ones to
deallocated memory, are allowed.
Rollup of 7 pull requests
Successful merges:
- #104505 (Remove double spaces after dots in comments)
- #106784 (prevent E0512 from emitting [type error] by checking the references_error)
- #106834 (new trait solver: only consider goal changed if response is not identity)
- #106889 (Mention the lack of `windows_mut` in `windows`)
- #106963 (Use `scope_expr_id` from `ProbeCtxt`)
- #106970 (Switch to `EarlyBinder` for `item_bounds` query)
- #106980 (Hide `_use_mk_alias_ty_instead` in `<AliasTy as Debug>::fmt`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Switch to `EarlyBinder` for `item_bounds` query
Part of the work to finish #105779 (also see https://github.com/rust-lang/types-team/issues/78).
Several queries `X` have a `bound_X` variant that wraps the output in `EarlyBinder`. This adds `EarlyBinder` to the return type of the `item_bounds` query and removes `bound_item_bounds`.
r? `@lcnr`
Put `noundef` on all scalars that don't allow uninit
Previously, it was only put on scalars with range validity invariants like bool, was uninit was obviously invalid for those.
Since then, we have normatively declared all uninit primitives to be undefined behavior and can therefore put `noundef` on them.
The remaining concern was the `mem::uninitialized` function, which cause quite a lot of UB in the older parts of the ecosystem. After #99182, this function now doesn't return uninit values anymore, making users of it safe from this change.
The only real sources of UB where people could encounter uninit primitives are `MaybeUninit::uninit().assume_init()`, which has always be clear in the docs about being UB and from heap allocations (like reading from the spare capacity of a vec). This is hopefully rare enough to not break anything.
cc `@nagisa` `@scottmcm` `@nikic`
Constify `TypeId` ordering impls
Tracking issue: #101871
Adding const ordering to `TypeId` allows rtti crates to optimize some casting scenarios (without transmuting to `u64`). This would also prevent these crates from breaking if the underlying type is changed from `u64` to something different.
Feature gate: `#![feature(const_cmp_type_id)]`
Document wf constraints on control flow in cleanup blocks
Was recently made aware of [this code](a377893da2/compiler/rustc_codegen_ssa/src/mir/analyze.rs (L247-L368)), which has this potential ICE: a377893da2/compiler/rustc_codegen_ssa/src/mir/analyze.rs (L308-L314)
Roughly speaking, the code there is attempting to partition the cleanup blocks into funclets that satisfy a "unique successor" property, and the ICE is set off if that's not possible. This PR documents the well-formedness constraints that MIR must satisfy to avoid setting off that ICE.
The constraints documented are slightly stronger than the cases in which the ICE would have been set off in that code. This is necessary though, since whether or not that ICE gets set off can depend on iteration order in some graphs.
This sort of constraint is kind of ugly, but I don't know a better alternative at the moment. It's worth knowing that two important optimizations are still correct:
- Removing edges in the cfg: Fewer edges => fewer paths => stronger dominance relations => more contractions, and more contractions can't turn a forest into not-a-forest.
- Contracting an edge u -> v when u only has one successor and v only has one predecessor: u already dominated v, so this contraction was going to happen anyway.
There is definitely a MIR opt somewhere that can run afoul of this, but I don't know where it is. `@saethlin` was able to set it off though, so maybe he'll be able to shed some light on it.
r? `@RalfJung` I suppose, and cc `@tmiasko` who might have insight/opinions on this
fix: don't emit `E0711` if `staged_api` not enabled
Fixes#106589
Simple fix, added UI test.
As an aside, it seems a lot of features are susceptible to this, `E0711` stands out to me because it's perma-unstable and we are effectively exposing an implementation detail.
Previously, it was only put on scalars with range validity invariants
like bool, was uninit was obviously invalid for those.
Since then, we have normatively declared all uninit primitives to be
undefined behavior and can therefore put `noundef` on them.
The remaining concern was the `mem::uninitialized` function, which cause
quite a lot of UB in the older parts of the ecosystem. This function now
doesn't return uninit values anymore, making users of it safe from this
change.
The only real sources of UB where people could encounter uninit
primitives are `MaybeUninit::uninit().assume_init()`, which has always
be clear in the docs about being UB and from heap allocations (like
reading from the spare capacity of a vec. This is hopefully rare enough
to not break anything.
