Split out `ty::AliasTerm` from `ty::AliasTy`
Splitting out `AliasTerm` (for use in project and normalizes goals) and `AliasTy` (for use in `ty::Alias`)
r? lcnr
Rename some `FulfillmentErrorCode`/`ObligationCauseCode` variants to be less redundant
1. Rename some `FulfillmentErrorCode` variants.
2. Always use `ObligationCauseCode::` to prefix a code, rather than using a glob import and naming them through `traits::`.
3. Rename some `ObligationCauseCode` variants -- I wasn't particularly thorough with thinking of a new names for these, so could workshop them if necessary.
4. Misc stuff from renaming.
r? lcnr
Rename `Generics::params` to `Generics::own_params`
I hope this makes it slightly more obvious that `generics.own_params` is insufficient when considering nested items. I didn't actually audit any of the usages, for the record.
r? lcnr
`InferCtxt::next_{ty,const}_var*` all take an origin, but the
`param_def_id` is almost always `None`. This commit changes them to just
take a `Span` and build the origin within the method, and adds new
methods for the rare cases where `param_def_id` might not be `None`.
This avoids a lot of tedious origin building.
Specifically:
- next_ty_var{,_id_in_universe,_in_universe}: now take `Span` instead of
`TypeVariableOrigin`
- next_ty_var_with_origin: added
- next_const_var{,_in_universe}: takes Span instead of ConstVariableOrigin
- next_const_var_with_origin: added
- next_region_var, next_region_var_in_universe: these are unchanged,
still take RegionVariableOrigin
The API inconsistency (ty/const vs region) seems worth it for the
large conciseness improvements.
The starting point for this was identical comments on two different
fields, in `ast::VariantData::Struct` and `hir::VariantData::Struct`:
```
// FIXME: investigate making this a `Option<ErrorGuaranteed>`
recovered: bool
```
I tried that, and then found that I needed to add an `ErrorGuaranteed`
to `Recovered::Yes`. Then I ended up using `Recovered` instead of
`Option<ErrorGuaranteed>` for these two places and elsewhere, which
required moving `ErrorGuaranteed` from `rustc_parse` to `rustc_ast`.
This makes things more consistent, because `Recovered` is used in more
places, and there are fewer uses of `bool` and
`Option<ErrorGuaranteed>`. And safer, because it's difficult/impossible
to set `recovered` to `Recovered::Yes` without having emitted an error.
Do not ICE on `AnonConst`s in `diagnostic_hir_wf_check`
Fixes#122989
Below is the snippet from #122989 that ICEs:
```rust
trait Traitor<const N: N<2> = 1, const N: N<2> = N> {
fn N(&N) -> N<2> {
M
}
}
trait N<const N: Traitor<2> = 12> {}
```
The `AnonConst` that triggers the ICE is the `2` in the param `const N: N<2> = 1`. The currently existing code in `diagnostic_hir_wf_check` deals only with `AnonConst`s that are default values of some param, but the `2` is not a default value. It is just an `AnonConst` HIR node inside a `TraitRef` HIR node corresponding to `N<2>`. Therefore the existing code cannot handle it and this PR ensures that it does.
Make `Bounds.clauses` private
Construct it through `Bounds::default()`, then consume the clauses via the method `Bounds::clauses()`.
This helps with effects desugaring where `clauses()` is not only the clauses within the `clauses` field.
Some hir cleanups
It seemed odd to not put `AnonConst` in the arena, compared with the other types that we did put into an arena. This way we can also give it a `Span` without growing a lot of other HIR data structures because of the extra field.
r? compiler
Use `tcx.types.unit` instead of `Ty::new_unit(tcx)`
I don't think there is any need for the function, given that we can just access the `.types`, similarly to all other primitives?
Cleanup: Replace item names referencing GitHub issues or error codes with something more meaningful
**lcnr** in https://github.com/rust-lang/rust/pull/117164#pullrequestreview-1969935387:
> […] while I know that there's precendent to name things `Issue69420`, I really dislike this as it requires looking up the issue to figure out the purpose of such a variant. Actually referring to the underlying issue, e.g. `AliasMayNormToUncovered` or whatever and then linking to the issue in a doc comment feels a lot more desirable to me. We should ideally rename all the functions and enums which currently use issue numbers.
I've grepped through `compiler/` like crazy and think that I've found all instances of this pattern.
However, I haven't renamed `compute_2229_migrations_*`. Should I?
The first commit introduces an abhorrent and super long name for an item because naming is hard but also scary looking / unwelcoming names are good for things related to temporary-ish backcompat hacks. I'll let you discover it by yourself.
Contains a bit of drive-by cleanup and a diag migration bc that was the simplest option.
r? lcnr or compiler
Lazily normalize inside trait ref during orphan check & consider ty params in rigid alias types to be uncovered
Fixes#99554, fixesrust-lang/types-team#104.
Fixes#114061.
Supersedes #100555.
Tracking issue for the future compatibility lint: #124559.
r? lcnr
delegation: Support renaming, and async, const, extern "ABI" and C-variadic functions
Also allow delegating to functions with opaque types (`impl Trait`).
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created, which seems like a reasonable behavior.
(Such delegation items will cause query cycles when used in trait impls, but it can be fixed later.)
Part of https://github.com/rust-lang/rust/issues/118212.
Also allow `impl Trait` in delegated functions.
The delegation item will refer to the original opaque type from the callee, fresh opaque type won't be created.
Rollup of 3 pull requests
Successful merges:
- #124003 (Dellvmize some intrinsics (use `u32` instead of `Self` in some integer intrinsics))
- #124169 (Don't fatal when calling `expect_one_of` when recovering arg in `parse_seq`)
- #124286 (Subtree sync for rustc_codegen_cranelift)
r? `@ghost`
`@rustbot` modify labels: rollup
Dellvmize some intrinsics (use `u32` instead of `Self` in some integer intrinsics)
This implements https://github.com/rust-lang/compiler-team/issues/693 minus what was implemented in #123226.
Note: I decided to _not_ change `shl`/... builder methods, as it just doesn't seem worth it.
r? ``@scottmcm``
Do `check_coroutine_obligations` once per typeck root
We only need to do `check_coroutine_obligations` once per typeck root, especially since the new solver can't really (easily) associate which obligations correspond to which coroutines.
This requires us to move the checks for sized coroutine fields into `mir_coroutine_witnesses`, but that's fine imo.
r? lcnr
Suggest using type args directly instead of equality constraint
When type arguments are written erroneously using an equality constraint we suggest specifying them directly without the equality constraint.
Fixes#122162
Changes the diagnostic in the issue from:
```rust
error[E0229]: associated type bindings are not allowed here
9 | impl std::cmp::PartialEq<Rhs = T> for S {
| ^^^^^^^ associated type not allowed here
|
```
to
```rust
error[E0229]: associated type bindings are not allowed here
9 | impl std::cmp::PartialEq<Rhs = T> for S {
| ^^^^^^^ associated type not allowed here
|
help: to use `T` as a generic argument specify it directly
|
| impl std::cmp::PartialEq<T> for S {
| ~
```
weak lang items are not allowed to be #[track_caller]
For instance the panic handler will be called via this import
```rust
extern "Rust" {
#[lang = "panic_impl"]
fn panic_impl(pi: &PanicInfo<'_>) -> !;
}
```
A `#[track_caller]` would add an extra argument and thus make this the wrong signature.
The 2nd commit is a consistency rename; based on the docs [here](https://doc.rust-lang.org/unstable-book/language-features/lang-items.html) and [here](https://rustc-dev-guide.rust-lang.org/lang-items.html) I figured "lang item" is more widely used. (In the compiler output, "lang item" and "language item" seem to be pretty even.)
fix normalizing in different `ParamEnv`s with the same `InferCtxt`
This PR changes the key of the projection cache from just `AliasTy` to `(AliasTy, ParamEnv)` to allow normalizing in different `ParamEnv`s without resetting caches. Previously, normalizing the same alias in different param envs would always reuse the cached result from the first normalization, which is incorrect if the projection clauses in the param env have changed.
Fixing this bug allows us to get rid of `InferCtxt::clear_caches`, which was only used by the `AutoTraitFinder`, because it requires normalizing in different param envs.
r? `@fmease`
Fix capturing duplicated lifetimes via parent in `precise_captures` (`impl use<'...>`)
For technical reasons related to the way that `Self` and `T::Assoc` are lowered from HIR -> `rustc_middle::ty`, an opaque may mention in its bounds both the original early-bound lifetime from the parent `impl`/`fn`, *and* the *duplicated* early-bound lifetime on the opaque.
This is fine -- and has been fine since `@cjgillot` rewrote the way we handled opaque lifetime captures, and we went further to allow this behavior explicitly in https://github.com/rust-lang/rust/pull/115659. It's worthwhile to read this PR's technical section to recall how this duplication works and when it acts surprisingly.
The problem here is that the check that make sure that `impl use<'a, 'b>` lists all of the opaque's captured lifetimes wasn't smart enough to consider both these captured lifetimes and the original lifetimes they're duplicated from to be equal. This PR fixes that.
r? oli-obk
Don't repeatedly duplicate TAIT lifetimes for each subsequently nested TAIT
Make it so that nested TAITs inherit the lifetimes from their parent item, not their parent TAIT. This is because we don't need to re-duplicate lifetimes for nested TAITs over and over, since the only lifetimes they can capture are from the parent item anyways.
This mirrors how RPITs work. This is **not** a functional change that should be observable, since the whole point of duplicating lifetimes and marking the shadowed ones (and uncaptured ones) as bivariant is designed to *not* be observable.
r? oli-obk
Match ergonomics 2024: miscellaneous code cleanups
- Store `ByRef` instead of `BindingAnnotation` in `PatInfo`
- Rename `BindingAnnotation` to `BindingMode`
r? ``@Nadrieril``
cc #123076
``@rustbot`` label A-patterns
Delay span bug when `Self` kw resolves to `DefKind::{Mod,Trait}`
Catch the case where `kw::Self` is recovered in the parser and causes us to subsequently resolve `&self`'s implicit type to something that's not a type.
This check could be made more accurate, though I'm not sure how hard we have to try here.
Fixes#123988
Implement syntax for `impl Trait` to specify its captures explicitly (`feature(precise_capturing)`)
Implements `impl use<'a, 'b, T, U> Sized` syntax that allows users to explicitly list the captured parameters for an opaque, rather than inferring it from the opaque's bounds (or capturing *all* lifetimes under 2024-edition capture rules). This allows us to exclude some implicit captures, so this syntax may be used as a migration strategy for changes due to #117587.
We represent this list of captured params as `PreciseCapturingArg` in AST and HIR, resolving them between `rustc_resolve` and `resolve_bound_vars`. Later on, we validate that the opaques only capture the parameters in this list.
We artificially limit the feature to *require* mentioning all type and const parameters, since we don't currently have support for non-lifetime bivariant generics. This can be relaxed in the future.
We also may need to limit this to require naming *all* lifetime parameters for RPITIT, since GATs have no variance. I have to investigate this. This can also be relaxed in the future.
r? `@oli-obk`
Tracking issue:
- https://github.com/rust-lang/rust/issues/123432
Fix pretty HIR for anon consts in diagnostics
This removes the `NoAnn` printer which skips over nested bodies altogether, which is confusing, and requires users of `{ty|qpath|pat}_to_string` to pass in `&tcx` which now impleemnts `hir_pretty::PpAnn`.
There's one case where this "regresses" by actually printing out the body of the anon const -- we could suppress that, but I don't expect people to actually get anon consts like that unless they're fuzzing, tbh.
r? estebank
Remove `TypeVariableOriginKind` and `ConstVariableOriginKind`
It's annoying to have to import `TypeVariableOriginKind` just to fill it with `MiscVariable` for almost every use. Every other usage other than `TypeParameterDefinition` wasn't even used -- I can see how it may have been useful once for debugging, but I do quite a lot of typeck debugging and I've never really needed it.
So let's just remove it, and keep around the only useful thing which is the `DefId` of the param for `var_for_def`.
This is based on #123006, which removed the special use of `TypeVariableOriginKind::OpaqueInference`, which I'm pretty sure I was the one that added.
r? lcnr or re-roll to types
Fix various bugs in `ty_kind_suggestion`
Consolidates two implementations of `ty_kind_suggestion`
Fixes some misuse of the empty param-env
Fixes a problem where we suggested `(42)` instead of `(42,)` for tuple suggestions
Suggest a value when `return;`, making it consistent with `break;`
Fixes#123906
Call lower_const_param instead of duplicating the code
Follow up of #123689
r? `@oli-obk`
I had this commit in my old branch that I had forgotten about, `@fmease` pointed about this in #123689
I've left the branches that are not `Range` as do nothing as that's what we are currently doing but maybe we want to err or something.
Tweak value suggestions in `borrowck` and `hir_analysis`
Unify the output of `suggest_assign_value` and `ty_kind_suggestion`.
Ideally we'd make these a single function, but doing so would likely require modify the crate dependency tree.
Propagate temporary lifetime extension into if and match.
This PR makes this work:
```rust
let a = if true {
..;
&temp() // used to error, but now gets lifetime extended
} else {
..;
&temp() // used to error, but now gets lifetime extended
};
```
and
```rust
let a = match () {
_ => {
..;
&temp() // used to error, but now gets lifetime extended
}
};
```
to make it consistent with:
```rust
let a = {
..;
&temp() // lifetime is extended
};
```
This is one small part of [the temporary lifetimes work](https://github.com/rust-lang/lang-team/issues/253).
This part is backwards compatible (so doesn't need be edition-gated), because all code affected by this change previously resulted in a hard error.
Unify the output of `suggest_assign_value` and `ty_kind_suggestion`.
Ideally we'd make these a single function, but doing so would likely require modify the crate dependency tree.
Ensure we do not accidentally insert new early aborts in the analysis passes
pulling the infallible part out into a separate function makes sure that someone needs to change the signature in order to regress this.
We only want to stop compilation in the presence of errors after all analyses are done, but before we start running lints.
per-item we can still stop doing work if previous queries returned errors, but that's a separate story.
Pass list of defineable opaque types into canonical queries
This eliminates `DefiningAnchor::Bubble` for good and brings the old solver closer to the new one wrt cycles and nested obligations. At that point the difference between `DefiningAnchor::Bind([])` and `DefiningAnchor::Error` was academic. We only used the difference for some sanity checks, which actually had to be worked around in places, so I just removed `DefiningAnchor` entirely and just stored the list of opaques that may be defined.
fixes#108498
fixes https://github.com/rust-lang/rust/issues/116877
* [x] run crater
- https://github.com/rust-lang/rust/pull/122077#issuecomment-2013293931
Assert that args are actually compatible with their generics, rather than just their count
Right now we just check that the number of args is right, rather than actually checking the kinds. Uplift a helper fn that I wrote from trait selection to do just that. Found a couple bugs along the way.
r? `@lcnr` or `@fmease` (or anyone really lol)
Rename `expose_addr` to `expose_provenance`
`expose_addr` is a bad name, an address is just a number and cannot be exposed. The operation is actually about the provenance of the pointer.
This PR thus changes the name of the method to `expose_provenance` without changing its return type. There is sufficient precedence for returning a useful value from an operation that does something else without the name indicating such, e.g. [`Option::insert`](https://doc.rust-lang.org/nightly/std/option/enum.Option.html#method.insert) and [`MaybeUninit::write`](https://doc.rust-lang.org/nightly/std/mem/union.MaybeUninit.html#method.write).
Returning the address is merely convenient, not a fundamental part of the operation. This is implied by the fact that integers do not have provenance since
```rust
let addr = ptr.addr();
ptr.expose_provenance();
let new = ptr::with_exposed_provenance(addr);
```
must behave exactly like
```rust
let addr = ptr.expose_provenance();
let new = ptr::with_exposed_provenance(addr);
```
as the result of `ptr.expose_provenance()` and `ptr.addr()` is the same integer. Therefore, this PR removes the `#[must_use]` annotation on the function and updates the documentation to reflect the important part.
~~An alternative name would be `expose_provenance`. I'm not at all opposed to that, but it makes a stronger implication than we might want that the provenance of the pointer returned by `ptr::with_exposed_provenance`[^1] is the same as that what was exposed, which is not yet specified as such IIUC. IMHO `expose` does not make that connection.~~
A previous version of this PR suggested `expose` as name, libs-api [decided on](https://github.com/rust-lang/rust/pull/122964#issuecomment-2033194319) `expose_provenance` to keep the symmetry with `with_exposed_provenance`.
CC `@RalfJung`
r? libs-api
[^1]: I'm using the new name for `from_exposed_addr` suggested by #122935 here.
Assert `FnDef` kind
Only found one bug, where we were using the variant def id rather than its ctor def id to make the `FnDef` for a `type_of`
r? fmease
rename ptr::from_exposed_addr -> ptr::with_exposed_provenance
As discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-opsem/topic/To.20expose.20or.20not.20to.20expose/near/427757066).
The old name, `from_exposed_addr`, makes little sense as it's not the address that is exposed, it's the provenance. (`ptr.expose_addr()` stays unchanged as we haven't found a better option yet. The intended interpretation is "expose the provenance and return the address".)
The new name nicely matches `ptr::without_provenance`.
Make sure to insert `Sized` bound first into clauses list
#120323 made it so that we don't insert an implicit `Sized` bound whenever we see an *explicit* `Sized` bound. However, since the code that inserts implicit sized bounds puts the bound as the *first* in the list, that means that it had the **side-effect** of possibly meaning we check `Sized` *after* checking other trait bounds.
If those trait bounds result in ambiguity or overflow or something, it may change how we winnow candidates. (**edit: SEE** #123303) This is likely the cause for the regression in https://github.com/rust-lang/rust/issues/123279#issuecomment-2028899598, since the impl...
```rust
impl<T: Job + Sized> AsJob for T { // <----- changing this to `Sized + Job` or just `Job` (which turns into `Sized + Job`) will FIX the issue.
}
```
...looks incredibly suspicious.
Fixes [after beta-backport] #123279.
Alternative is to revert #120323. I don't have a strong opinion about this, but think it may be nice to keep the diagnostic changes around.
De-LLVM the unchecked shifts [MCP#693]
This is just one part of the MCP (https://github.com/rust-lang/compiler-team/issues/693), but it's the one that IMHO removes the most noise from the standard library code.
Seems net simpler this way, since MIR already supported heterogeneous shifts anyway, and thus it's not more work for backends than before.
r? WaffleLapkin
Add `Ord::cmp` for primitives as a `BinOp` in MIR
Update: most of this OP was written months ago. See https://github.com/rust-lang/rust/pull/118310#issuecomment-2016940014 below for where we got to recently that made it ready for review.
---
There are dozens of reasonable ways to implement `Ord::cmp` for integers using comparison, bit-ops, and branches. Those differences are irrelevant at the rust level, however, so we can make things better by adding `BinOp::Cmp` at the MIR level:
1. Exactly how to implement it is left up to the backends, so LLVM can use whatever pattern its optimizer best recognizes and cranelift can use whichever pattern codegens the fastest.
2. By not inlining those details for every use of `cmp`, we drastically reduce the amount of MIR generated for `derive`d `PartialOrd`, while also making it more amenable to MIR-level optimizations.
Having extremely careful `if` ordering to μoptimize resource usage on broadwell (#63767) is great, but it really feels to me like libcore is the wrong place to put that logic. Similarly, using subtraction [tricks](https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign) (#105840) is arguably even nicer, but depends on the optimizer understanding it (https://github.com/llvm/llvm-project/issues/73417) to be practical. Or maybe [bitor is better than add](https://discourse.llvm.org/t/representing-in-ir/67369/2?u=scottmcm)? But maybe only on a future version that [has `or disjoint` support](https://discourse.llvm.org/t/rfc-add-or-disjoint-flag/75036?u=scottmcm)? And just because one of those forms happens to be good for LLVM, there's no guarantee that it'd be the same form that GCC or Cranelift would rather see -- especially given their very different optimizers. Not to mention that if LLVM gets a spaceship intrinsic -- [which it should](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Suboptimal.20inlining.20in.20std.20function.20.60binary_search.60/near/404250586) -- we'll need at least a rustc intrinsic to be able to call it.
As for simplifying it in Rust, we now regularly inline `{integer}::partial_cmp`, but it's quite a large amount of IR. The best way to see that is with 8811efa88b (diff-d134c32d028fbe2bf835fef2df9aca9d13332dd82284ff21ee7ebf717bfa4765R113) -- I added a new pre-codegen MIR test for a simple 3-tuple struct, and this PR change it from 36 locals and 26 basic blocks down to 24 locals and 8 basic blocks. Even better, as soon as the construct-`Some`-then-match-it-in-same-BB noise is cleaned up, this'll expose the `Cmp == 0` branches clearly in MIR, so that an InstCombine (#105808) can simplify that to just a `BinOp::Eq` and thus fix some of our generated code perf issues. (Tracking that through today's `if a < b { Less } else if a == b { Equal } else { Greater }` would be *much* harder.)
---
r? `@ghost`
But first I should check that perf is ok with this
~~...and my true nemesis, tidy.~~
Use the `Align` type when parsing alignment attributes
Use the `Align` type in `rustc_attr::parse_alignment`, removing the need to call `Align::from_bytes(...).unwrap()` later in the compilation process.
This is just one part of the MCP, but it's the one that IMHO removes the most noise from the standard library code.
Seems net simpler this way, since MIR already supported heterogeneous shifts anyway, and thus it's not more work for backends than before.
Match ergonomics 2024: implement mutable by-reference bindings
Implements the mutable by-reference bindings portion of match ergonomics 2024 (#123076), with the `mut ref`/`mut ref mut` syntax, under feature gate `mut_ref`.
r? `@Nadrieril`
`@rustbot` label A-patterns A-edition-2024
Suggest associated type bounds on problematic associated equality bounds
Fixes#105056. TL;DR: Suggest `Trait<Ty: Bound>` on `Trait<Ty = Bound>` in Rust >=2021.
~~Blocked on #122055 (stabilization of `associated_type_bounds`), I'd say.~~ (merged)
Avoid some unnecessary query invocations.
Specifically this inlines `const_eval_poly` and avoids computing the generic params, the param env, normalizing the param env and erasing lifetimes on everything.
should fix the perf regression from https://github.com/rust-lang/rust/pull/121087
Delegation: fix ICE on `bound_vars` divergence
Fixes https://github.com/rust-lang/rust/issues/122550.
Bug was caused by divergence between lowered type and corresponding `bound_vars` in `late_bound_vars_map`. In this patch `bound_vars` calculation for delegation item is moved from `lower_fn_ty` to `resolve_bound_vars` query.
r? `@petrochenkov`
Mention Register Size in `#[warn(asm_sub_register)]`
Fixes#121593
Displays the register size information obtained from `suggest_modifier()` and `default_modifier()`.
refactor check_{lang,library}_ub: use a single intrinsic
This enacts the plan I laid out [here](https://github.com/rust-lang/rust/pull/122282#issuecomment-1996917998): use a single intrinsic, called `ub_checks` (in aniticpation of https://github.com/rust-lang/compiler-team/issues/725), that just exposes the value of `debug_assertions` (consistently implemented in both codegen and the interpreter). Put the language vs library UB logic into the library.
This makes it easier to do something like https://github.com/rust-lang/rust/pull/122282 in the future: that just slightly alters the semantics of `ub_checks` (making it more approximating when crates built with different flags are mixed), but it no longer affects whether these checks can happen in Miri or compile-time.
The first commit just moves things around; I don't think these macros and functions belong into `intrinsics.rs` as they are not intrinsics.
r? `@saethlin`
Rollup of 11 pull requests
Successful merges:
- #120577 (Stabilize slice_split_at_unchecked)
- #122698 (Cancel `cargo update` job if there's no updates)
- #122780 (Rename `hir::Local` into `hir::LetStmt`)
- #122915 (Delay a bug if no RPITITs were found)
- #122916 (docs(sync): normalize dot in fn summaries)
- #122921 (Enable more mir-opt tests in debug builds)
- #122922 (-Zprint-type-sizes: print the types of awaitees and unnamed coroutine locals.)
- #122927 (Change an ICE regression test to use the original reproducer)
- #122930 (add panic location to 'panicked while processing panic')
- #122931 (Fix some typos in the pin.rs)
- #122933 (tag_for_variant follow-ups)
r? `@ghost`
`@rustbot` modify labels: rollup
Rename `hir::Local` into `hir::LetStmt`
Follow-up of #122776.
As discussed on [zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Improve.20naming.20of.20.60ExprKind.3A.3ALet.60.3F).
I made this change into a separate PR because I'm less sure about this change as is. For example, we have `visit_local` and `LocalSource` items. Is it fine to keep these two as is (I supposed it is but I prefer to ask) or not? Having `Node::Local(LetStmt)` makes things more explicit but is it going too far?
r? ```@oli-obk```
Let codegen decide when to `mem::swap` with immediates
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.
Thus this PR introduces a new `typed_swap` intrinsic with a fallback body, and replaces that fallback implementation when swapping immediates or scalar pairs.
r? oli-obk
Replaces #111744, and means we'll never need more libs PRs like #111803 or #107140
Rollup of 8 pull requests
Successful merges:
- #114009 (compiler: allow transmute of ZST arrays with generics)
- #122195 (Note that the caller chooses a type for type param)
- #122651 (Suggest `_` for missing generic arguments in turbofish)
- #122784 (Add `tag_for_variant` query)
- #122839 (Split out `PredicatePolarity` from `ImplPolarity`)
- #122873 (Merge my contributor emails into one using mailmap)
- #122885 (Adjust better spastorino membership to triagebot's adhoc_groups)
- #122888 (add a couple more tests)
r? `@ghost`
`@rustbot` modify labels: rollup
Split out `PredicatePolarity` from `ImplPolarity`
Because having to deal with a third `Reservation` level in all the trait solver code is kind of weird.
r? `@lcnr` or `@oli-obk`
Suggest `_` for missing generic arguments in turbofish
The compiler may suggest unusable generic type names for missing generic arguments in an expression context:
```rust
fn main() {
(0..1).collect::<Vec>()
}
```
> help: add missing generic argument
>
> (0..1).collect::<Vec<T>>()
but `T` is not a valid name in this context, and this suggestion won't compile.
I've changed it to use `_` inside method calls (turbofish), so it will suggest `(0..1).collect::<Vec<_>>()` which _may_ compile.
It's possible that the suggested `_` will be ambiguous, but there is very extensive E0283 that will help resolve that, which is more helpful than a basic "cannot find type `T` in this scope" users would get otherwise.
Out of caution to limit scope of the change I've limited it to just turbofish, but I suspect `_` could be the better choice in more cases. Perhaps in all expressions?
Gracefully handle `AnonConst` in `diagnostic_hir_wf_check()`
Instead of running the WF check on the `AnonConst` itself we run it on the `ty` of the generic param of which the `AnonConst` is the default value.
Fixes#122199
This makes it easier to read the trait definition for newcomers:
Sorted from least “complex” to most “complex” followed by trivial “plumbing”
and grouped by area.
* Move `allow_infer` above all `*_infer` methods
* It's the least complex method of those
* Allows the `*_infer` to be placed right next to each other
* Move `probe_ty_param_bounds` further down right next to `lower_assoc_ty` and `probe_adt`
* It's more complex than the `infer` methods, it should come “later”
* Now all required lowering functions are grouped together
* Move the “plumbing” function `set_tainted_by_errors` further down
below any actual lowering methods.
* Provided method should come last
Most of the tracing calls didn't fully leverage the power of `tracing`.
For example, several of them used to hard-code method names / tracing spans
as well as variable names. Use `#[instrument]` and `?var` / `%var` (etc.) instead.
In my opinion, this is the proper way to migrate them from the old
AstConv nomenclature to the new HIR ty lowering one.
Several (doc) comments were super outdated or didn't provide enough context.
Some doc comments shoved everything in a single paragraph without respecting
the fact that the first paragraph should be a single sentence because rustdoc
treats these as item descriptions / synopses on module pages.
Split an item bounds and an item's super predicates
This is the moral equivalent of #107614, but instead for predicates this applies to **item bounds**. This PR splits out the item bounds (i.e. *all* predicates that are assumed to hold for the alias) from the item *super predicates*, which are the subset of item bounds which share the same self type as the alias.
## Why?
Much like #107614, there are places in the compiler where we *only* care about super-predicates, and considering predicates that possibly don't have anything to do with the alias is problematic. This includes things like closure signature inference (which is at its core searching for `Self: Fn(..)` style bounds), but also lints like `#[must_use]`, error reporting for aliases, computing type outlives predicates.
Even in cases where considering all of the `item_bounds` doesn't lead to bugs, unnecessarily considering irrelevant bounds does lead to a regression (#121121) due to doing extra work in the solver.
## Example 1 - Trait Aliases
This is best explored via an example:
```
type TAIT<T> = impl TraitAlias<T>;
trait TraitAlias<T> = A + B where T: C;
```
The item bounds list for `Tait<T>` will include:
* `Tait<T>: A`
* `Tait<T>: B`
* `T: C`
While `item_super_predicates` query will include just the first two predicates.
Side-note: You may wonder why `T: C` is included in the item bounds for `TAIT`? This is because when we elaborate `TraitAlias<T>`, we will also elaborate all the predicates on the trait.
## Example 2 - Associated Type Bounds
```
type TAIT<T> = impl Iterator<Item: A>;
```
The `item_bounds` list for `TAIT<T>` will include:
* `Tait<T>: Iterator`
* `<Tait<T> as Iterator>::Item: A`
But the `item_super_predicates` will just include the first bound, since that's the only bound that is relevant to the *alias* itself.
## So what
This leads to some diagnostics duplication just like #107614, but none of it will be user-facing. We only see it in the UI test suite because we explicitly disable diagnostic deduplication.
Regarding naming, I went with `super_predicates` kind of arbitrarily; this can easily be changed, but I'd consider better names as long as we don't block this PR in perpetuity.
Use hir::Node helper methods instead of repeating the same impl multiple times
I wanted to do something entirely different and stumbled upon a bunch of cleanups
Provide structured suggestion for `#![feature(foo)]`
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
Reject overly generic assoc const binding types
Split off from #119385 to make #119385 easier to review.
---
In the *instantiated* type of assoc const bindings
1. reject **early-bound generic params**
* Provide a rich error message instead of ICE'ing ([#108271](https://github.com/rust-lang/rust/issues/108271)).
* This is a temporary and semi-artificial restriction until the arrival of *generic const generics*.
* It's quite possible that rustc could already perfectly support this subset of generic const generics if we just removed some checks (some `.no_bound_vars().expect(…)`) but even if that was the case, I'd rather gate it behind a new feature flag. Reporting an error instead of ICE'ing is a good first step towards an eventual feature gate error.
2. reject **escaping late-bound generic params**
* They lead to ICEs before & I'm pretty sure that they remain incorrect even in a world with *generic const generics*
---
Together with #118668 & #119385, this supersedes #118360.
Fixes#108271.
```
error: `S2<'_>` is forbidden as the type of a const generic parameter
--> $DIR/lifetime-in-const-param.rs:5:23
|
LL | struct S<'a, const N: S2>(&'a ());
| ^^
|
= note: the only supported types are integers, `bool` and `char`
help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
|
LL + #![feature(adt_const_params)]
|
```
Fix#55941.
Making `libcore` decide this is silly; the backend has so much better information about when it's a good idea.
So introduce a new `typed_swap` intrinsic with a fallback body, but replace that implementation for immediates and scalar pairs.
Remove obsolete parameter `speculative` from `instantiate_poly_trait_ref`
In #122527 I totally missed that `speculative` has become obsolete with the removal of `hir_trait_to_predicates` / due to #113671.
Fixes#114635.
r? `@compiler-errors`
Split refining_impl_trait lint into _reachable, _internal variants
As discussed in https://github.com/rust-lang/rust/issues/119535#issuecomment-1909352040:
> We discussed this today in triage and developed a consensus to:
>
> * Add a separate lint against impls that refine a return type defined with RPITIT even when the trait is not crate public.
> * Place that in a lint group along with the analogous crate public lint.
> * Create an issue to solicit feedback on these lints (or perhaps two separate ones).
> * Have the warnings displayed with each lint reference this issue in a similar manner to how we do that today with the required `Self: '0'` bound on GATs.
> * Make a note to review this feedback on 2-3 release cycles.
This points users to https://github.com/rust-lang/rust/issues/121718 to leave feedback.
hir: Remove `opt_local_def_id_to_hir_id` and `opt_hir_node_by_def_id`
Also replace a few `hir_node()` calls with `hir_node_by_def_id()`.
Follow up to https://github.com/rust-lang/rust/pull/120943.
Clean up AstConv
Split off from #120926 to make it only contain the renaming & (doc) comment updates.
Any changes other than that which have accumulated over time are now part of this PR.
Let's be disciplined ;) Inspired by https://github.com/rust-lang/rust/pull/120926#issuecomment-1997984483.
---
* Remove `hir_trait_to_predicates`
* Unused since #113671
* Inline `create_args_for_ast_trait_ref`
* Only had a single call site
* Having it as a separate method didn't gain us anything
* Use an if-let guard somewhere to avoid unwrapping
* Avoid explicit trait object lifetimes
* More legible, stylistic-only (the updated code is 100% semantically identical)
* Use explicitly elided lifetimes in impl headers, they get elaborated to distinct lifetimes
* Make use of [object lifetime defaulting](https://doc.rust-lang.org/reference/lifetime-elision.html#default-trait-object-lifetimes) for a trait object type inside of a reference type somewhere
* Use preexisting dedicated method `ItemCtxt::to_ty` over `<dyn AstConv<'_>>::ast_ty_to_ty`
* Use preexisting dedicated method `AstConv::astconv` over explicit coercions
* Simplify the function signature of `create_args_for_ast_path` and of `check_generic_arg_count`
* In both cases redundant information was passed rendering the call sites verbose and confusing
* No perf impact (tested in [#120926](https://github.com/rust-lang/rust/pull/120926))
* Move diagnostic method `report_ambiguous_associated_type` from `astconv` to `astconv::errors`
* The submodule `errors` exists specifically for that purpose
* Use it to keep the main module clean & short
Ensure RPITITs are created before def-id freezing
From the test:
```rust
// `ty::Error` in a trait ref will silence any missing item errors, but will also
// prevent the `associated_items` query from being called before def ids are frozen.
```
Essentially, the code that checks that `impl`s have all their items (`check_impl_items_against_trait`) is also (implicitly) responsible for fetching the `associated_items` query before, but since we early return here:
c2901f5435/compiler/rustc_hir_analysis/src/check/check.rs (L732-L737)
...that means that this never happens for trait refs that reference errors.
Fixes#122518
r? oli-obk
Create some minimal HIR for associated opaque types
`LocalDefId`s for opaque types in traits and impls are created after AST -> HIR lowering, so they don't have corresponding HIR and return their various properties through fed queries.
In this PR I also feed some core HIR-related queries for these `LocalDefId`s (which happen to be HIR owners).
As a result all `LocalDefId`s now have corresponding `HirId`s and HIR nodes, and "optional" methods like `opt_local_def_id_to_hir_id` and `opt_hir_node_by_def_id` can be removed.
Follow up to https://github.com/rust-lang/rust/pull/120206.
Make `DefiningAnchor::Bind` only store the opaque types that may be constrained, instead of the current infcx root item.
This makes `Bind` almost always be empty, so we can start forwarding it to queries, allowing us to remove `Bubble` entirely (not done in this PR)
The only behaviour change is in diagnostics.
r? `@lcnr` `@compiler-errors`
Rollup of 15 pull requests
Successful merges:
- #116791 (Allow codegen backends to opt-out of parallel codegen)
- #116793 (Allow targets to override default codegen backend)
- #117458 (LLVM Bitcode Linker: A self contained linker for nvptx and other targets)
- #119385 (Fix type resolution of associated const equality bounds (take 2))
- #121438 (std support for wasm32 panic=unwind)
- #121893 (Add tests (and a bit of cleanup) for interior mut handling in promotion and const-checking)
- #122080 (Clarity improvements to `DropTree`)
- #122152 (Improve diagnostics for parenthesized type arguments)
- #122166 (Remove the unused `field_remapping` field from `TypeLowering`)
- #122249 (interpret: do not call machine read hooks during validation)
- #122299 (Store backtrace for `must_produce_diag`)
- #122318 (Revision-related tweaks for next-solver tests)
- #122320 (Use ptradd for vtable indexing)
- #122328 (unix_sigpipe: Replace `inherit` with `sig_dfl` in syntax tests)
- #122330 (bootstrap readme: fix, improve, update)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix type resolution of associated const equality bounds (take 2)
Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding.
---
Together with #118668 (merged) and #121258, this supersedes #118360.
Fixes#118040.
r? ``@ghost``
Run a single huge par_body_owners instead of many small ones after each other.
This improves parallel rustc parallelism by avoiding the bottleneck after each individual `par_body_owners` (because it needs to wait for queries to finish, so if there is one long running one, a lot of cores will be idle while waiting for the single query).
This improves parallel rustc parallelism by avoiding the bottleneck after each individual `par_body_owners` (because it needs to wait for queries to finish, so if there is one long running one, a lot of cores will be idle while waiting for the single query).
Expose the Freeze trait again (unstably) and forbid implementing it manually
non-emoji version of https://github.com/rust-lang/rust/pull/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 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: https://github.com/google/zerocopy/issues/941
cc ```@RalfJung```
T-lang signed off on reexposing this unstably: https://github.com/rust-lang/rust/pull/121501#issuecomment-1969827742
Distinguish between library and lang UB in assert_unsafe_precondition
As described in https://github.com/rust-lang/rust/pull/121583#issuecomment-1963168186, `assert_unsafe_precondition` now explicitly distinguishes between language UB (conditions we explicitly optimize on) and library UB (things we document you shouldn't do, and maybe some library internals assume you don't do).
`debug_assert_nounwind` was originally added to avoid the "only at runtime" aspect of `assert_unsafe_precondition`. Since then the difference between the macros has gotten muddied. This totally revamps the situation.
Now _all_ preconditions shall be checked with `assert_unsafe_precondition`. If you have a precondition that's only checkable at runtime, do a `const_eval_select` hack, as done in this PR.
r? RalfJung
