incr.comp.: Don't automatically enable -Zshare-generics for incr. comp. builds.
So far the compiler would automatically enable sharing of monomorphizations for incremental builds. That was OK because without (Thin)LTO this could have very little impact on the runtime performance of the generated code. However, since https://github.com/rust-lang/rust/pull/53673, ThinLTO and incr. comp. can be combined, so the trade-off is not as clear anymore.
This PR removes the automatic tie between the two options. Whether monomorphizations are shared between crates or not now _only_ depends on the optimization level.
r? @alexcrichton
aarch64-pc-windows-msvc: Don't link libpanic_unwind to libtest.
This implements the suggestion from https://github.com/rust-lang/rust/issues/54190#issuecomment-422904437 in order to unbreak bootstrapping for the `aarch64-pc-windows-msvc` target. With this applied and using MSVC 15.8.3 for linking the bootstrap actually works and I can cross-compile a hello-world program.
r? @alexcrichton
resolve: Do not block derive helper resolutions on single import resolutions
Derive helpers currently conflict with anything else, so if some resolution from a single import appears later, it will result in error anyway.
Fixes https://github.com/rust-lang/rust/issues/54471 (stable-to-beta regression)
r? @ghost
Introduce the partition_dedup/by/by_key methods for slices
This PR propose to add three methods to the slice type, the `partition_dedup`, `partition_dedup_by` and `partition_dedup_by_key`. The two other methods are based on `slice::partition_dedup_by`.
These methods take a mutable slice, deduplicates it and moves all duplicates to the end of it, returning two mutable slices, the first containing the deduplicated elements and the second all the duplicates unordered.
```rust
let mut slice = [1, 2, 2, 3, 3, 2];
let (dedup, duplicates) = slice.partition_dedup();
assert_eq!(dedup, [1, 2, 3, 2]);
assert_eq!(duplicates, [3, 2]);
```
The benefits of adding these methods is that it is now possible to:
- deduplicate a slice without having to allocate and possibly clone elements on the heap, really useful for embedded stuff that can't allocate for example.
- not loose duplicate elements, because, when using `Vec::dedup`, duplicates elements are dropped. These methods add more flexibillity to the user.
Note that this is near a copy/paste of the `Vec::dedup_by` function, once this method is stable the goal is to replace the algorithm in `Vec` by the following.
```rust
pub fn Vec::dedup_by<F>(&mut self, same_bucket: F)
where F: FnMut(&mut T, &mut T) -> bool
{
let (dedup, _) = self.as_mut_slice().partition_dedup_by(same_bucket);
let len = dedup.len();
self.truncate(len);
}
```
Derive helpers conflict currently conflict with anything else, so if some resolution from a single import appears later, it will result in error anyway
Make "await" a pseudo-edition keyword
This change makes "await" ident an error in 2018 edition without async_await
feature and adds "await" to the 2018 edition keyword lint group that
suggest migration on the 2015 edition.
cc https://github.com/rust-lang/rust/issues/53834
r? @nikomatsakis
Support an explicit annotation for marker traits
From the tracking issue for rust-lang/rfcs#1268:
> It seems obvious that we should make a `#[marker]` annotation. ~ https://github.com/rust-lang/rust/issues/29864#issuecomment-368959441
This PR allows you to put `#[marker]` on a trait, at which point:
- [x] The trait must not have any items ~~All of the trait's items must have defaults~~
- [x] Any impl of the trait must be empty (not override any items)
- [x] But impls of the trait are allowed to overlap
r? @nikomatsakis
[NLL] Be more permissive when checking access due to Match
Partially addresses #53114. notably, we should now have parity with AST borrowck. Matching on uninitialized values is still forbidden.
* ~~Give fake borrows for match their own `BorrowKind`~~
* ~~Allow borrows with this kind to happen on values that are already mutably borrowed.~~
* ~~Track borrows with this type even behind shared reference dereferences and consider all accesses to be deep when checking for conflicts with this borrow type. See [src/test/ui/issues/issue-27282-mutate-before-diverging-arm-3.rs](cb5c989598 (diff-a2126cd3263a1f5342e2ecd5e699fbc6)) for an example soundness issue this fixes (a case of #27282 that wasn't handled correctly).~~
* Create a new `BorrowKind`: `Shallow` (name can be bike-shed)
* `Shallow` borrows differ from shared borrows in that
* When we check for access we treat them as a `Shallow(Some(_))` read
* When we check for conflicts with them, if the borrow place is a strict prefix of the access place then we don't consider that a conflict.
* For example, a `Shallow` borrow of `x` does not conflict with any access or borrow of `x.0` or `*x`
* Remove the current fake borrow in matches.
* When building matches, we take a `Shallow` borrow of any `Place` that we switch on or bind in a match, and any prefix of those places. (There are some optimizations where we do fewer borrows, but this shouldn't change semantics)
* `match x { &Some(1) => (), _ => (), }` would `Shallow` borrow `x`, `*x` and `(*x as Some).0` (the `*x` borrow is unnecessary, but I'm not sure how easy it would be to remove.)
* Replace the fake discriminant read with a `ReadForMatch`.
* Change ReadForMatch to only check for initializedness (to prevent `let x: !; match x {}`), but not conflicting borrows. It is still considered a use for liveness and `unsafe` checking.
* Give special cased error messages for this kind of borrow.
Table from the above issue after this PR
| Thing | AST | MIR | Want | Example |
| --- | --- | --- | --- |---|
| `let _ = <unsafe-field>` | 💚 | 💚 | ❌ | [playground](https://play.rust-lang.org/?gist=bb7843e42fa5318c1043d04bd72abfe4&version=nightly&mode=debug&edition=2015) |
| `match <unsafe_field> { _ => () }` | ❌ | ❌ | ❌ | [playground](https://play.rust-lang.org/?gist=3e3af05fbf1fae28fab2aaf9412fb2ea&version=nightly&mode=debug&edition=2015) |
| `let _ = <moved>` | 💚 | 💚 | 💚 | [playground](https://play.rust-lang.org/?gist=91a6efde8288558e584aaeee0a50558b&version=nightly&mode=debug&edition=2015) |
| `match <moved> { _ => () }` | ❌ | ❌ | 💚 | [playground](https://play.rust-lang.org/?gist=804f8185040b2fe131f2c4a64b3048ca&version=nightly&mode=debug&edition=2015) |
| `let _ = <borrowed>` | 💚 | 💚 | 💚 | [playground](https://play.rust-lang.org/?gist=0e487c2893b89cb772ec2f2b7c5da876&version=nightly&mode=debug&edition=2015) |
| `match <borrowed> { _ => () }` | 💚 | 💚 | 💚 | [playground](https://play.rust-lang.org/?gist=0e487c2893b89cb772ec2f2b7c5da876&version=nightly&mode=debug&edition=2015) |
r? @nikomatsakis
This change makes "await" ident an error in 2018 edition without async_await
feature and adds "await" to the 2018 edition keyword lint group that
suggest migration on the 2015 edition.
Rewrite docs for pointer methods
This takes over https://github.com/rust-lang/rust/pull/51016 by @ecstatic-morse. They did most of the work, I just did some editing.
However, I realized one problem: This updates the docs for the "free functions" in `core::ptr`, but it does not update the copies of these docs for the inherent methods of the `*const T` and `*mut T` types. These getting out-of-sync is certainly bad, but I also don't feel like copying all this stuff around. Instead, we should remove this redundancy. Any good ideas?
[NLL] Rework checking for borrows conflicting with drops
Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
`places_conflict`.
We also now handle enums containing `Drop` types.
Closes#53569
r? @nikomatsakis
cc @pnkfelix
update rls to 32d457717ce37babef199fe4984b1e20d4e108d4
I patched rls to use the `rustc_tools_utils` supplied by the clippy submodule to get around the tidy warning.
Should fix rls and toolstate.
avoid loading constructor attributes in AdtDef decoding
During metadata loading, the AdtDefs for every ADT in the universe need
to be loaded (for example, for coherence of builtin traits). For that,
the attributes of the AdtDef need to be loaded too.
The attributes of a struct are duplicated between 2 def ids - the
constructor def-id, and the "type" def id. Loading attributes for both
def-ids, which was done in #53721, slowed the compilation of small
crates by 2-3%. This PR makes sure we only load the attributes for the
"type" def-id, avoiding the slowdown.
r? @eddyb & cc @nnethercote
Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
places_conflict.
This also allows us to handle enums in a simpler way, since we don't
have to construct any new places.
When dropping a self-borrowing struct we shouldn't add a "values in a
scope are dropped in the opposite order they are defined" message,
since there is only one value being dropped.
