bors [Tue, 1 Oct 2019 07:56:52 +0000 (07:56 +0000)]
Auto merge of #64946 - Centril:rollup-66mj5o0, r=Centril
Rollup of 10 pull requests
Successful merges:
- #63674 (syntax: Support modern attribute syntax in the `meta` matcher)
- #63931 (Stabilize macros in some more positions)
- #64887 (syntax: recover trailing `|` in or-patterns)
- #64895 (async/await: improve not-send errors)
- #64896 (Remove legacy grammar)
- #64907 (A small amount of tidying-up factored out from PR #64648)
- #64928 (Add tests for some issues)
- #64930 (Silence unreachable code lint from await desugaring)
- #64935 (Improve code clarity)
- #64937 (Deduplicate closure type errors)
Rollup merge of #64937 - estebank:dedup-closure-err, r=Centril
Deduplicate closure type errors
Closure typing obligations flow in both direcitons to properly infer
types. Because of this, we will get 2 type errors whenever there's
an unfulfilled obligation. To avoid this, we deduplicate them in the
`InferCtxt`.
Rollup merge of #64907 - alexreg:tidy-up, r=Mark-Simulacrum
A small amount of tidying-up factored out from PR #64648
As requested by @Mark-Simulacrum, I put this in a separate commit to make it easier to review. (As far as I can tell, no violations of the policy here, and they are simply in a separate PR because they're not directly related to the import of that PR.)
Rollup merge of #64895 - davidtwco:issue-64130-async-error-definition, r=nikomatsakis
async/await: improve not-send errors
cc #64130.
```
note: future does not implement `std::marker::Send` because this value is used across an await
--> $DIR/issue-64130-non-send-future-diags.rs:15:5
|
LL | let g = x.lock().unwrap();
| - has type `std::sync::MutexGuard<'_, u32>`
LL | baz().await;
| ^^^^^^^^^^^ await occurs here, with `g` maybe used later
LL | }
| - `g` is later dropped here
```
For example (this also shows that we are sensitive to the typo `||`):
```
error: a trailing `|` is not allowed in an or-pattern
--> $DIR/remove-leading-vert.rs:33:11
|
LL | A || => {}
| - ^^ help: remove the `||`
| |
| while parsing this or-pattern starting here
|
= note: alternatives in or-patterns are separated with `|`, not `||`
```
Rollup merge of #63931 - petrochenkov:stabmac, r=Centril
Stabilize macros in some more positions
- Fn-like macros and attribute macros in `extern` blocks
- Fn-like procedural macros in type positions
- ~Attribute macros on inline modules~ (moved to https://github.com/rust-lang/rust/pull/64273)
Rollup merge of #63674 - petrochenkov:meta2, r=Centril
syntax: Support modern attribute syntax in the `meta` matcher
Where "modern" means https://github.com/rust-lang/rust/pull/57367:
```
PATH
PATH `(` TOKEN_STREAM `)`
PATH `[` TOKEN_STREAM `]`
PATH `{` TOKEN_STREAM `}`
```
Unfortunately, `meta` wasn't future-proofed using the `FOLLOW` token set like other matchers (https://github.com/rust-lang/rust/issues/34011), so code like `$meta:meta {` or `$meta:meta [` may break, and we need a crater run to find out how often this happens in practice.
Closes https://github.com/rust-lang/rust/issues/49629 (by fully supporting `meta` rather than removing it.)
bors [Tue, 1 Oct 2019 02:31:48 +0000 (02:31 +0000)]
Auto merge of #64932 - tmandry:rollup-7t8x1nz, r=tmandry
Rollup of 9 pull requests
Successful merges:
- #64377 (Add long error explanation for E0493)
- #64786 (Use https for curl when building for linux)
- #64828 (Graphviz debug output for generic dataflow analysis)
- #64838 (Add long error explanation for E0550)
- #64891 (Fix `vec![x; n]` with null raw fat pointer zeroing the pointer metadata)
- #64893 (Zero-initialize `vec![None; n]` for `Option<&T>`, `Option<&mut T>` and `Option<Box<T>>`)
- #64911 (Fixed a misleading documentation issue #64844)
- #64921 (Add test for issue-64662)
- #64923 (Add missing links for mem::needs_drop)
Esteban Küber [Tue, 1 Oct 2019 00:48:22 +0000 (17:48 -0700)]
Deduplicate closure type errors
Closure typing obligations flow in both direcitons to properly infer
types. Because of this, we will get 2 type errors whenever there's
an unfulfilled obligation. To avoid this, we deduplicate them in the
`InferCtxt`.
David Wood [Wed, 25 Sep 2019 12:58:41 +0000 (13:58 +0100)]
async/await: improve obligation errors
This commit improves obligation errors for async/await:
```
note: future does not implement `std::marker::Send` because this value is used across an
await
--> $DIR/issue-64130-non-send-future-diags.rs:15:5
|
LL | let g = x.lock().unwrap();
| - has type `std::sync::MutexGuard<'_, u32>`
LL | baz().await;
| ^^^^^^^^^^^ await occurs here, with `g` maybe used later
LL | }
| - `g` is later dropped here
```
Rollup merge of #64891 - SimonSapin:vec-of-fat-raw-ptr, r=sfackler
Fix `vec![x; n]` with null raw fat pointer zeroing the pointer metadata
https://github.com/rust-lang/rust/pull/49496 introduced specialization based on:
```rust
unsafe impl<T: ?Sized> IsZero for *mut T {
fn is_zero(&self) -> bool {
(*self).is_null()
}
}
```
… to call `RawVec::with_capacity_zeroed` for creating `Vec<*mut T>`, which is incorrect for fat pointers since `<*mut T>::is_null` only looks at the data component. That is, a fat pointer can be “null” without being made entirely of zero bits.
This commit fixes it by removing the `?Sized` bound on this impl (and the corresponding `*const T` one). This regresses `vec![x; n]` with `x` a null raw slice of length zero, but that seems exceptionally uncommon. (Vtable pointers are never null, so raw trait objects would not take the fast path anyway.)
An alternative to keep the `?Sized` bound (or even generalize to `impl<U: Copy> IsZero for U`) would be to cast to `&[u8]` of length `size_of::<U>()`, but the optimizer seems not to be able to propagate alignment information and sticks with comparing one byte at a time:
https://rust.godbolt.org/z/xQFkwL
----
Without the library change, the new test fails as follows:
Rollup merge of #64828 - ecstatic-morse:generic-dataflow-graphviz, r=oli-obk
Graphviz debug output for generic dataflow analysis
A follow up to #64566.
This outputs graphviz diagrams in the generic dataflow engine when `#[rustc_mir(borrowck_graphviz_postflow="suffix.dot")]` is set on an item. This code is based on [`dataflow/graphviz.rs`](https://github.com/rust-lang/rust/blob/master/src/librustc_mir/dataflow/graphviz.rs), but displays different information since there are no "gen"/"kill" sets and transfer functions cannot be coalesced in the generic analysis. As a result, we show the dataflow state at the start and end of each block, as well as the changes resulting from each statement. I also render the state bitset in full (`{_1,_2}`) instead of hex-encoded as the current renderer does (`06`).
Auto merge of #64600 - scottmcm:no-slice-tryfold-unroll, r=bluss
Remove manual unrolling from slice::Iter(Mut)::try_fold
While this definitely helps sometimes (particularly for trivial closures), it's also a pessimization sometimes, so it's better to leave this to (hypothetical) future LLVM improvements instead of forcing this on everyone.
I think it's better for the advice to be that sometimes you need to unroll manually than you sometimes need to not-unroll manually (like #64545).
---
For context see https://github.com/rust-lang/rust/pull/64572#issuecomment-532961046
Auto merge of #64673 - Mark-Simulacrum:opt-match-ck, r=oli-obk
Optimize try_eval_bits to avoid layout queries
This specifically targets match checking, but is possibly more widely
useful as well. In code with large, single-value match statements, we
were previously spending a lot of time running layout_of for the
primitive types (integers, chars) -- which is essentially useless. This
optimizes the code to avoid those query calls by directly obtaining the
size for these types, when possible.
It may be worth considering adding a `size_of` query in the future which
might be far faster, especially if specialized for "const" cases --
match arms being the most obvious example. It's possibly such a function
would benefit from *not* being a query as well, since it's trivially
evaluatable from the sty for many cases whereas a query needs to hash
the input and such.
Mark Rousskov [Sat, 21 Sep 2019 22:39:35 +0000 (18:39 -0400)]
Optimize try_eval_bits to avoid layout queries
This specifically targets match checking, but is possibly more widely
useful as well. In code with large, single-value match statements, we
were previously spending a lot of time running layout_of for the
primitive types (integers, chars) -- which is essentially useless. This
optimizes the code to avoid those query calls by directly obtaining the
size for these types, when possible.
It may be worth considering adding a `size_of` query in the future which
might be far faster, especially if specialized for "const" cases --
match arms being the most obvious example. It's possibly such a function
would benefit from *not* being a query as well, since it's trivially
evaluatable from the sty for many cases whereas a query needs to hash
the input and such.
Auto merge of #64902 - Centril:rollup-1i431vs, r=Centril
Rollup of 6 pull requests
Successful merges:
- #64691 (Point at definition when misusing ADT)
- #64735 (Add long error explanation for E0533)
- #64825 (Point at enclosing match when expecting `()` in arm)
- #64858 (Add support for relating slices in `super_relate_consts`)
- #64894 (syntax: fix dropping of attribute on first param of non-method assocated fn)
- #64898 (fixed typo)
Rollup merge of #64894 - Centril:fix-64682, r=petrochenkov
syntax: fix dropping of attribute on first param of non-method assocated fn
Fixes #64682.
The general idea is that we bake parsing of `self` into `parse_param_general` and then we just use standard list parsing. Overall, this simplifies the parsing and makes it more consistent.
Simon Sapin [Sun, 29 Sep 2019 08:45:47 +0000 (10:45 +0200)]
Fix `vec![x; n]` with null raw fat pointer zeroing the pointer metadata
https://github.com/rust-lang/rust/pull/49496 introduced specialization based on:
```
unsafe impl<T: ?Sized> IsZero for *mut T {
fn is_zero(&self) -> bool {
(*self).is_null()
}
}
```
… to call `RawVec::with_capacity_zeroed` for creating `Vec<*mut T>`,
which is incorrect for fat pointers
since `<*mut T>::is_null` only looks at the data component.
That is, a fat pointer can be “null” without being made entirely of zero bits.
This commit fixes it by removing the `?Sized` bound on this impl
(and the corresponding `*const T` one).
This regresses `vec![x; n]` with `x` a null raw slice of length zero,
but that seems exceptionally uncommon.
(Vtable pointers are never null, so raw trait objects would not take
the fast path anyway.
An alternative to keep the `?Sized` bound
(or even generalize to `impl<U: Copy> IsZero for U`)
would be to cast to `&[u8]` of length `size_of::<U>()`,
but the optimizer seems not to be able to propagate alignment information
and sticks with comparing one byte at a time:
https://rust.godbolt.org/z/xQFkwL
----
Without the library change, the new test fails as follows:
Auto merge of #64886 - Centril:rollup-30dqh8j, r=Centril
Rollup of 5 pull requests
Successful merges:
- #63492 (Remove redundancy from the implementation of C variadics.)
- #64589 (Differentiate AArch64 bare-metal targets between hf and non-hf.)
- #64799 (Fix double panic when printing query stack during an ICE)
- #64824 (No StableHasherResult everywhere)
- #64884 (Add pkg-config to dependency list if building for Linux on Linux)
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