Some promotion cleanup
Based on top of both https://github.com/rust-lang/rust/pull/75502 and https://github.com/rust-lang/rust/pull/75585, this does some cleanup of the promotion code. The last 2 commits are new.
* Remove the remaining cases where `const fn` is treated different from `fn`. This means no longer promoting ptr-to-int casts, raw ptr operations, and union field accesses in `const fn` -- or anywhere, for that matter. These are all unstable in const-context so this should not break any stable code. Fixes https://github.com/rust-lang/rust/issues/75586.
* ~~Promote references to statics even outside statics (i.e., in functions) for consistency.~~
* Promote `&mut []` everywhere, not just in non-`const` functions, for consistency.
* Explain why we do not promote deref's of statics outside statics. ~~(This is the only remaining direct user of `const_kind`.)~~
This can only land once the other two PRs land; I am mostly putting this up already because I couldn't wait ;) and to get some feedback from `@rust-lang/wg-const-eval` .
shim: monomorphic `FnPtrShim`s during construction
Fixes#69925.
This PR adjusts MIR shim construction so that substitutions are applied to function pointer shims during construction, rather than during codegen (as determined by `substs_for_mir_body`).
r? `@eddyb`
Implement a generic Destination Propagation optimization on MIR
This takes the work that was originally started by `@eddyb` in https://github.com/rust-lang/rust/pull/47954, and then explored by me in https://github.com/rust-lang/rust/pull/71003, and implements it in a general (ie. not limited to acyclic CFGs) and dataflow-driven way (so that no additional infrastructure in rustc is needed).
The pass is configured to run at `mir-opt-level=2` and higher only. To enable it by default, some followup work on it is still needed:
* Performance needs to be evaluated. I did some light optimization work and tested against `tuple-stress`, which caused trouble in my last attempt, but didn't go much in depth here.
* We can also enable the pass only at `opt-level=2` and higher, if it is too slow to run in debug mode, but fine when optimizations run anyways.
* Debuginfo needs to be fixed after locals are merged. I did not look into what is required for this.
* Live ranges of locals (aka `StorageLive` and `StorageDead`) are currently deleted. We either need to decide that this is fine, or if not, merge the variable's live ranges (or remove these statements entirely – https://github.com/rust-lang/rust/issues/68622).
Some benchmarks of the pass were done in https://github.com/rust-lang/rust/pull/72635.
give *even better* suggestion when matching a const range
notice that the err already has "constant defined here"
so this is now *exceedingly clear*
extension to #76222
r? @estebank
do not inline black_box when building for Miri
We cannot do the assembly trick in Miri, but let's at least make sure MIR inlining does not circumvent the black_box.
Also use black_box instead of local optimization barriers in a few const tests.
Add test for checking duplicated branch or-patterns
This adds a regression test for checking `or-patterns` in MIR as shown in #75439.
This doesn't introduce a fix as I'm not sure where it would go(I suspect maybe here: src/librustc_mir_build/build/matches/mod.rs), and I'm not particularly able to fix it.
cc: @lzutao
compare generic constants using `AbstractConst`s
This is a MVP of rust-lang/compiler-team#340. The changes in this PR should only be relevant if `feature(const_evaluatable_checked)` is enabled.
~~currently based on top of #76559, so blocked on that.~~
r? `@oli-obk` cc `@varkor` `@eddyb`
Issue 72408 nested closures exponential
This fixes#72408.
Nested closures were resulting in exponential compilation time.
This PR is enhancing asymptotic complexity, but also increasing the constant, so I would love to see perf run results.
[mir-opt] Disable the `ConsideredEqual` logic in SimplifyBranchSame opt
The logic is currently broken and we need to disable it to fix a beta
regression (see #76803)
r? `@oli-obk`
Mostly to fix ui/issues/issue-37311-type-length-limit/issue-37311.rs.
Most parts of the compiler can handle deeply nested types with a lot
of duplicates just fine, but some parts still attempt to naively
traverse type tree.
Before such problems were caught by type length limit check,
but now these places will have to be changed to handle
duplicated types gracefully.
This fixes#72408.
Nested closures were resulting in exponential compilation time.
As a performance optimization this change introduces MiniSet,
which is a simple small storage optimized set.
Improve E0118
- Changes the "base type" terminology to "nominal type" (according to the [reference](https://doc.rust-lang.org/stable/reference/items/implementations.html#inherent-implementations)).
- Suggests removing a reference, if one is present on the type.
- Clarify what is meant by a "nominal type".
closes#69392
This is my first not-entirely-trivial PR, so please let me know if I missed anything or if something could be improved. Though I probably won't be able to fix anything in the upcoming week.
Change error message for ty param in const
This PR introduces the following changes:
* Change error message for type param in a const expression when using
`min_const_generics`
* Change `ParamInNonTrivialAnonConst` to contain an extra `bool` used for
distinguishing whether the passed-in symbol is a type or a value.
Fixes#76701
Add array_windows fn
This mimicks the functionality added by array_chunks, and implements a const-generic form of
`windows`. It makes egregious use of `unsafe`, but by necessity because the array must be
re-interpreted as a slice of arrays, and unlike array_chunks this cannot be done by casting the
original array once, since each time the index is advanced it needs to move one element, not
`N`.
I'm planning on adding more tests, but this should be good enough as a premise for the functionality.
Notably: should there be more functions overwritten for the iterator implementation/in general?
~~I've marked the issue as #74985 as there is no corresponding exact issue for `array_windows`, but it's based of off `array_chunks`.~~
Edit: See Issue #75027 created by @lcnr for tracking issue
~~Do not merge until I add more tests, please.~~
r? @lcnr
Updated issue to #75027
Update to rm oob access
And hopefully fix docs as well
Fixed naming conflict in test
Fix test which used 1-indexing
Nth starts from 0, woops
Fix a bunch of off by 1 errors
See https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=757b311987e3fae1ca47122969acda5a
Add even more off by 1 errors
And also write `next` and `next_back` in terms of `nth` and `nth_back`.
Run fmt
Fix forgetting to change fn name in test
add nth_back test & document unsafe
Remove as_ref().unwrap()
Documented occurrences of unsafe, noting what invariants are maintained
improve const infer error
cc #72328
reduces it from
```
error[E0282]: type annotations needed
--> src/main.rs:17:5
|
17 | Foo.bar().bar().bar().bar().baz();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: unable to infer the value of a const parameter
```
to
```
error[E0282]: type annotations needed
--> $DIR/method-chain.rs:21:33
|
LL | Foo.bar().bar().bar().bar().baz();
| ^^^
|
= note: cannot infer the value of the const parameter `N`
```
r? @varkor
fix syntax error in suggesting generic constraint in trait parameter
suggest `where T: Foo` for the first bound on a trait, then suggest
`, T: Foo` when the suggested bound would add to an existing set of
`where` clauses. `where T: Foo` may be the first bound if `T` has a
default, because we'd rather suggest
```
trait A<T=()> where T: Copy
```
than
```
trait A<T: Copy=()>
```
for legibility reasons.
the test case i added here is derived from [this reproduction](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=0bf3ace9f2a183d0bdbd748c6b8e3971):
```
struct B<T: Copy> {
t: T
}
trait A<T = ()> {
fn returns_constrained_type(&self, t: T) -> B<T> {
B { t }
}
}
```
where the suggested fix,
```
trait A<T = ()>, T: Copy { ... }
```
is in fact invalid syntax!
i also found an error in the existing suggestion for `trait Base<T = String>: Super<T>` where rustc would suggest `trait Base<T = String>: Super<T>, T: Copy`, but `T: Copy` is the first of the trait's `where` clauses and should be `where T: Copy` as well. the test for that suggestion expects invalid syntax, and has been revised to a compiler-pleasing `trait Base<T = String>: Super<T> where T: Copy`.
judging by https://github.com/rust-lang/rust/pull/70009 i'll.. cc @estebank ?
Make all methods of `Duration` unstably const
Make the following methods of `Duration` unstable const under `duration_const_2`:
- `from_secs_f64`
- `from_secs_f32`
- `mul_f64`
- `mul_f32`
- `div_f64`
- `div_f32`
This results in all methods of `Duration` being (unstable) const.
Moved the tests to `library` as part of #76268.
Possible because of #72449, which made the relevant `f32` and `f64` methods const.
Tracking issue: #72440
r? @ecstatic-morse
Note when a a move/borrow error is caused by a deref coercion
Fixes#73268
When a deref coercion occurs, we may end up with a move error if the
base value has been partially moved out of. However, we do not indicate
anywhere that a deref coercion is occuring, resulting in an error
message with a confusing span.
This PR adds an explicit note to move errors when a deref coercion is
involved. We mention the name of the type that the deref-coercion
resolved to, as well as the `Deref::Target` associated type being used.
