There are two traits, `InternAs` and `InternIteratorElement`. I found
them confusing to use, particularly this:
```
pub fn mk_tup<I: InternAs<Ty<'tcx>, Ty<'tcx>>>(self, iter: I) -> I::Output {
iter.intern_with(|ts| self.intern_tup(ts))
}
```
where I thought there might have been two levels of interning going on
(there isn't) due to the `intern_with`/`InternAs` + `intern_tup` naming.
And then I found the actual traits and impls themselves *very*
confusing.
- `InternAs` has a single impl, for iterators, with four type variables.
- `InternAs` is only implemented for iterators because it wouldn't
really make sense to implement for any other type. And you can't
really understand the trait without seeing that single impl, which is
suspicious.
- `InternAs` is basically just a wrapper for `InternIteratorElement`
which does all the actual work.
- Neither trait actually does any interning. They just have `Intern` in
their name because they are used *by* interning code.
- There are no comments.
So this commit improves things.
- It removes `InternAs` completely. This makes the `mk_*` function
signatures slightly more verbose -- two trait bounds instead of one --
but much easier to read, because you only need to understand one trait
instead of two.
- It renames `InternIteratorElement` as `CollectAndApply`. Likewise, it
renames its method `intern_with` as `collect_and_apply`. These names
describe better what's going on: we collect the iterator elements into
a slice and then apply a function to the slice.
- It adds comments, making clear that all this is all there just to
provide an optimized version of `f(&iter.collect::<Vec<_>>())`.
It took me a couple of attempts to come up with this commit. My initial
attempt kept `InternAs` around, but renamed things and added comments,
and I wasn't happy with it. I think this version is much better. The
resulting code is shorter, despite the addition of the comments.
`InternIteratorElement` is a trait used to intern values produces by
iterators. There are three impls, corresponding to iterators that
produce different types:
- One for `T`, which operates straightforwardly.
- One for `Result<T, E>`, which is fallible, and will fail early with an
error result if any of the iterator elements are errors.
- One for `&'a T`, which clones the items as it iterates.
That last one is bad: it's extremely easy to use it without realizing
that it clones, which goes against Rust's normal "explicit is better"
approach to cloning.
So this commit just removes it. In practice, there weren't many use
sites. For all but one of them `into_iter()` could be used, which avoids
the need for cloning. And for the one remaining case `copied()` is
used.
There are several `mk_foo`/`intern_foo` pairs, where the former takes an
iterator and the latter takes a slice. (This naming convention is bad,
but that's a fix for another PR.)
This commit changes several `mk_foo` occurrences into `intern_foo`,
avoiding the need for some `.iter()`/`.into_iter()` calls. Affected
cases:
- mk_type_list
- mk_tup
- mk_substs
- mk_const_list
Switch to `EarlyBinder` for `type_of` query
Part of the work to finish #105779 and implement 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 `type_of` query and removes `bound_type_of`.
r? `@lcnr`
Do not ICE on unmet trait alias impl bounds
Fixes#108132
I've also added some documentation to the `impl_def_id` field of `DerivedObligationCause` to try and minimise the risk of such errors in future.
r? `@compiler-errors`
Implement partial support for non-lifetime binders
This implements support for non-lifetime binders. It's pretty useless currently, but I wanted to put this up so the implementation can be discussed.
Specifically, this piggybacks off of the late-bound lifetime collection code in `rustc_hir_typeck::collect::lifetimes`. This seems like a necessary step given the fact we don't resolve late-bound regions until this point, and binders are sometimes merged.
Q: I'm not sure if I should go along this route, or try to modify the earlier nameres code to compute the right bound var indices for type and const binders eagerly... If so, I'll need to rename all these queries to something more appropriate (I've done this for `resolve_lifetime::Region` -> `resolve_lifetime::ResolvedArg`)
cc rust-lang/types-team#81
r? `@ghost`
Factor query arena allocation out from query caches
This moves the logic for arena allocation out from the query caches into conditional code in the query system. The specialized arena caches are removed. A new `QuerySystem` type is added in `rustc_middle` which contains the arenas, providers and query caches.
Performance seems to be slightly regressed:
<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check</td><td align="right">1.8053s</td><td align="right">1.8109s</td><td align="right"> 0.31%</td></tr><tr><td>🟣 <b>hyper</b>:check</td><td align="right">0.2600s</td><td align="right">0.2597s</td><td align="right"> -0.10%</td></tr><tr><td>🟣 <b>regex</b>:check</td><td align="right">0.9973s</td><td align="right">1.0006s</td><td align="right"> 0.34%</td></tr><tr><td>🟣 <b>syn</b>:check</td><td align="right">1.6048s</td><td align="right">1.6051s</td><td align="right"> 0.02%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check</td><td align="right">6.2992s</td><td align="right">6.3159s</td><td align="right"> 0.26%</td></tr><tr><td>Total</td><td align="right">10.9664s</td><td align="right">10.9922s</td><td align="right"> 0.23%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">1.0017s</td><td align="right"> 0.17%</td></tr></table>
Incremental performance is a bit worse:
<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check:initial</td><td align="right">2.2103s</td><td align="right">2.2247s</td><td align="right"> 0.65%</td></tr><tr><td>🟣 <b>hyper</b>:check:initial</td><td align="right">0.3335s</td><td align="right">0.3349s</td><td align="right"> 0.41%</td></tr><tr><td>🟣 <b>regex</b>:check:initial</td><td align="right">1.2597s</td><td align="right">1.2650s</td><td align="right"> 0.42%</td></tr><tr><td>🟣 <b>syn</b>:check:initial</td><td align="right">2.0521s</td><td align="right">2.0613s</td><td align="right"> 0.45%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check:initial</td><td align="right">7.8275s</td><td align="right">7.8583s</td><td align="right"> 0.39%</td></tr><tr><td>Total</td><td align="right">13.6832s</td><td align="right">13.7442s</td><td align="right"> 0.45%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">1.0046s</td><td align="right"> 0.46%</td></tr></table>
It does seem like LLVM optimizers struggle a bit with the current state of the query system.
Based on top of https://github.com/rust-lang/rust/pull/107782 and https://github.com/rust-lang/rust/pull/107802.
r? `@cjgillot`
Rollup of 7 pull requests
Successful merges:
- #106347 (More accurate spans for arg removal suggestion)
- #108057 (Prevent some attributes from being merged with others on reexports)
- #108090 (`if $c:expr { Some($r:expr) } else { None }` =>> `$c.then(|| $r)`)
- #108092 (note issue for feature(packed_bundled_libs))
- #108099 (use chars instead of strings where applicable)
- #108115 (Do not ICE on unmet trait alias bounds)
- #108125 (Add new people to the compiletest review rotation)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Optimize `mk_region`
PR #107869 avoiding some interning under `mk_ty` by special-casing `Ty` variants with simple (integer) bodies. This PR does something similar for regions.
r? `@compiler-errors`
Don't ICE in `might_permit_raw_init` if reference is polymorphic
Emitting optimized MIR for a polymorphic function may require computing layout of a type that isn't (yet) known. This happens in the instcombine pass, for example. Let's fail gracefully in that condition.
cc `@saethlin`
fixes#107999
Use `target` instead of `machine` for mir interpreter integer handling.
The naming of `machine` only makes sense from a mir interpreter internals perspective, but outside users talk about the `target` platform. As per https://github.com/rust-lang/rust/pull/108029#issuecomment-1429791015
r? `@RalfJung`
Avoid accessing HIR when it can be avoided
Experiment to see if it helps some incremental cases.
Will be rebased once https://github.com/rust-lang/rust/pull/107942 gets merged.
r? `@ghost`
Rollup of 7 pull requests
Successful merges:
- #105300 (rework min_choice algorithm of member constraints)
- #107163 (Remove some superfluous type parameters from layout.rs.)
- #107173 (Suggest the correct array length on mismatch)
- #107411 (Handle discriminant in DataflowConstProp)
- #107968 (Enable `#[thread_local]` on armv6k-nintendo-3ds)
- #108032 (Un📦ing the Resolver)
- #108060 (Revert to using `RtlGenRandom` as a fallback)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Handle discriminant in DataflowConstProp
cc ``@jachris``
r? ``@JakobDegen``
This PR attempts to extend the DataflowConstProp pass to handle propagation of discriminants. We handle this by adding 2 new variants to `TrackElem`: `TrackElem::Variant` for enum variants and `TrackElem::Discriminant` for the enum discriminant pseudo-place.
The difficulty is that the enum discriminant and enum variants may alias each another. This is the issue of the `Option<NonZeroUsize>` test, which is the equivalent of https://github.com/rust-lang/unsafe-code-guidelines/issues/84 with a direct write.
To handle that, we generalize the flood process to flood all the potentially aliasing places. In particular:
- any write to `(PLACE as Variant)`, either direct or through a projection, floods `(PLACE as OtherVariant)` for all other variants and `discriminant(PLACE)`;
- `SetDiscriminant(PLACE)` floods `(PLACE as Variant)` for each variant.
This implies that flooding is not hierarchical any more, and that an assignment to a non-tracked place may need to flood a tracked place. This is handled by `for_each_aliasing_place` which generalizes `preorder_invoke`.
As we deaggregate enums by putting `SetDiscriminant` last, this allows to propagate the value of the discriminant.
This refactor will allow to make https://github.com/rust-lang/rust/pull/107009 able to handle discriminants too.
use semantic equality for const param type equality assertion
Fixes#107898
See added test for what caused this ICE
---
The current in assertion in `relate.rs` is rather inadequate when keeping in mind future expansions to const generics:
- it will ICE when there are infer vars in a projection in a const param ty
- it will spurriously return false when either ty has infer vars because of using `==` instead of `infcx.at(..).eq`
- i am also unsure if it would be possible with `adt_const_params` to craft a situation where the const param type is not wf causing `normalize_erasing_regions` to `bug!` when we would have emitted a diagnostic.
This impl feels pretty Not Great to me although i am not sure what a better idea would be.
- We have to have the logic behind a query because neither `relate.rs` or `combine.rs` have access to trait solving machinery (without evaluating nested obligations this assert will become _far_ less useful under lazy norm, which consts are already doing)
- `relate.rs` does not have access to canonicalization machinery which is necessary in order to have types potentially containing infer vars in query arguments.
We could possible add a method to `TypeRelation` to do this assertion rather than a query but to avoid implementing the same logic over and over we'd probably end up with the logic in a free function somewhere in `rustc_trait_selection` _anyway_ so I don't think that would be much better.
We could also just remove this assertion, it should not actually be necessary for it to be present. It has caught some bugs in the past though so if possible I would like to keep it.
r? `@compiler-errors`
Much like there are specialized variants of `mk_ty`. This will enable
some optimization in the next commit.
Also rename the existing `re_error*` functions as `mk_re_error*`, for
consistency.
