bors [Wed, 18 Mar 2020 03:08:52 +0000 (03:08 +0000)]
Auto merge of #68915 - timvermeulen:non_fused_iter, r=Amanieu
Fix bugs in Peekable and Flatten when using non-fused iterators
I fixed a couple of bugs with regard to the `Peekable` and `Flatten`/`FlatMap` iterators when the underlying iterator isn't fused. For testing, I also added a `NonFused` iterator wrapper that panics when `next` or `next_back` is called on an iterator that has returned `None` before, which will hopefully make it easier to spot these mistakes in the future.
### Peekable
`Peekable::next_back` was implemented as
```rust
self.iter.next_back().or_else(|| self.peeked.take().and_then(|x| x))
```
which is incorrect because when the `peeked` field is `Some(None)`, then `None` has already been returned from the inner iterator and what it returns from `next_back` can no longer be relied upon. `test_peekable_non_fused` tests this.
### Flatten
When a `FlattenCompat` instance only has a `backiter` remaining (i.e. `self.frontiter` is `None` and `self.iter` is empty), then `next` will call `self.iter.next()` every time, so the `iter` field needs to be fused. I fixed it by giving it the type `Fuse<I>` instead of `I`, I think this is the only way to fix it. `test_flatten_non_fused_outer` tests this.
Furthermore, previously `FlattenCompat::next` did not set `self.frontiter` to `None` after it returned `None`, which is incorrect when the inner iterator type isn't fused. I just delegated it to `try_fold` because that already handles it correctly. `test_flatten_non_fused_inner` tests this.
Changes:
````
rustup https://github.com/rust-lang/rust/pull/68944
rustup https://github.com/rust-lang/rust/pull/69589/
Rustup to rust-lang/rust#69076
Don't convert Path to lossy str
Use `into_path`
Use pattern matching instead of manually checking condition
Fix typo
Remove git2 dependency.
Document that wildcard_imports doesn't warn about `use ...::prelude::*;`
Change changelog formatting
Update changelog_update doc to reflect the actual ordering of the changelog
Update CHANGELOG.md
````
bors [Tue, 17 Mar 2020 18:27:26 +0000 (18:27 +0000)]
Auto merge of #69519 - 12101111:remove-proc-macro-check, r=nagisa
Don't use static crt by default when build proc-macro
Don't check value of `crt-static` when build proc-macro crates, since they are always built dynamically.
For more information, see https://github.com/rust-lang/cargo/issues/7563#issuecomment-591965320
I hope this will fix issues about compiling `proc_macro` crates on musl host without bring more issues.
Fix https://github.com/rust-lang/cargo/issues/7563
bors [Tue, 17 Mar 2020 15:14:43 +0000 (15:14 +0000)]
Auto merge of #70072 - Centril:rollup-722hooh, r=Centril
Rollup of 7 pull requests
Successful merges:
- #68746 (Make macro metavars respect (non-)hygiene)
- #69688 (Move tidy check to mingw-check)
- #69735 (bootstrap: Use hash to determine if sanitizers needs to be rebuilt)
- #69922 (implement zeroed and uninitialized with MaybeUninit)
- #69956 (Ensure HAS_FREE_LOCAL_NAMES is set for ReFree)
- #70061 (Cosmetic fixes in documentation)
- #70064 (Update books)
Rollup merge of #70064 - ehuss:update-books, r=ehuss
Update books
## reference
4 commits in 559e09caa9661043744cf7af7bd88432d966f743..e2f11fe4d6a5ecb471c70323197da43c70cb96b6
2020-03-02 01:17:14 +0100 to 2020-03-10 06:59:24 +0100
- Update rustc-guide to rustc-dev-guide (rust-lang-nursery/reference#777)
- Fix expression and statement grammar. (rust-lang-nursery/reference#776)
- Fix grammar for tuple struct patterns. (rust-lang-nursery/reference#775)
- A typo? (rust-lang-nursery/reference#770)
## rust-by-example
3 commits in db57f899ea2a56a544c8d280cbf033438666273d..cb369ae95ca36b841960182d26f6d5d9b2e3cc18
2020-02-18 17:46:46 -0300 to 2020-03-14 12:13:22 -0500
- Use rust-lang/rust linkchecker on CI. (rust-lang/rust-by-example#1310)
- Rewrite freeze.md (rust-lang/rust-by-example#1314)
- Clarify type suffixing with example (rust-lang/rust-by-example#1312)
Rollup merge of #69922 - RalfJung:less-intrinsic, r=oli-obk
implement zeroed and uninitialized with MaybeUninit
This is the second attempt of doing such a change (first PR: https://github.com/rust-lang/rust/pull/62150). The last change [got reverted](https://github.com/rust-lang/rust/pull/63343) because it [caused](https://github.com/rust-lang/rust/issues/62825) some [issues](https://github.com/rust-lang/rust/issues/52898#issuecomment-512182438) in [code that incorrectly used these functions](https://github.com/erlepereira/x11-rs/issues/99).
Since then, the [problematic code has been fixed](https://github.com/erlepereira/x11-rs/pull/101), and rustc [gained a lint](https://github.com/rust-lang/rust/pull/63346) that is able to detect many misuses of these functions statically and a [dynamic check that panics](https://github.com/rust-lang/rust/pull/66059) instead of causing UB for some incorrect uses.
Rollup merge of #69735 - tmiasko:bootstrap-sanitizers-hash, r=Mark-Simulacrum
bootstrap: Use hash to determine if sanitizers needs to be rebuilt
* Rebuild sanitizers runtimes when LLVM submodule commit changes.
* When rebuilding LLVM / sanitizers, remove the stamp file before
starting the build process to invalidate previous build output.
bors [Tue, 17 Mar 2020 02:06:21 +0000 (02:06 +0000)]
Auto merge of #70062 - Centril:rollup-synwle8, r=Centril
Rollup of 7 pull requests
Successful merges:
- #69811 (resolve: Print import chains on privacy errors)
- #69870 (expand: Implement something similar to `#[cfg(accessible(path))]`)
- #69881 (VariantSizeDifferences: bail on SizeOverflow)
- #70000 (resolve: Fix regression in resolution of raw keywords in paths)
- #70029 (Bump the bootstrap compiler)
- #70046 (Use sublice patterns to avoid computing the len)
- #70049 (Fiddle `ParamEnv` through to a place that used to use `ParamEnv::empty` in a buggy manner)
Rollup merge of #69870 - petrochenkov:cfgacc, r=matthewjasper
expand: Implement something similar to `#[cfg(accessible(path))]`
cc https://github.com/rust-lang/rust/issues/64797
The feature is implemented as a `#[cfg_accessible(path)]` attribute macro rather than as `#[cfg(accessible(path))]` because it needs to wait until `path` becomes resolvable, and `cfg` cannot wait, but macros can wait.
Later we can think about desugaring or not desugaring `#[cfg(accessible(path))]` into `#[cfg_accessible(path)]`.
This implementation is also incomplete in the sense that it never returns "false" from `cfg_accessible(path)`, it requires some tweaks to resolve, which is not quite ready to answer queries like this during early resolution.
However, the most important part of this PR is not `cfg_accessible` itself, but expansion infrastructure for retrying expansions.
Before this PR we could say "we cannot resolve this macro path, let's try it later", with this PR we can say "we cannot expand this macro, let's try it later" as well.
This is a pre-requisite for
- turning `#[derive(...)]` into a regular attribute macro,
- properly supporting eager expansion for macros that cannot yet be resolved like
```
fn main() {
println!(not_available_yet!());
}
bors [Mon, 16 Mar 2020 20:49:26 +0000 (20:49 +0000)]
Auto merge of #68970 - matthewjasper:min-spec, r=nikomatsakis
Implement a feature for a sound specialization subset
This implements a new feature (`min_specialization`) that restricts specialization to a subset that is reasonable for the standard library to use.
The plan is to then:
* Update `libcore` and `liballoc` to compile with `min_specialization`.
* Add a lint to forbid use of `feature(specialization)` (and other unsound, type system extending features) in the standard library.
* Fix the soundness issues around `specialization`.
* Remove `min_specialization`
The rest of this is an overview from a comment in this PR
## Basic approach
To enforce this requirement on specializations we take the following approach:
1. Match up the substs for `impl2` so that the implemented trait and self-type match those for `impl1`.
2. Check for any direct use of `'static` in the substs of `impl2`.
3. Check that all of the generic parameters of `impl1` occur at most once in the *unconstrained* substs for `impl2`. A parameter is constrained if its value is completely determined by an associated type projection predicate.
4. Check that all predicates on `impl1` also exist on `impl2` (after matching substs).
## Example
Suppose we have the following always applicable impl:
```rust
impl<T> SpecExtend<T> for std::vec::IntoIter<T> { /* specialized impl */ }
impl<T, I: Iterator<Item=T>> SpecExtend<T> for I { /* default impl */ }
```
We get that the subst for `impl2` are `[T, std::vec::IntoIter<T>]`. `T` is constrained to be `<I as Iterator>::Item`, so we check only `std::vec::IntoIter<T>` for repeated parameters, which it doesn't have. The predicates of `impl1` are only `T: Sized`, which is also a predicate of impl2`. So this specialization is sound.
## Extensions
Unfortunately not all specializations in the standard library are allowed by this. So there are two extensions to these rules that allow specializing on some traits.
### rustc_specialization_trait
If a trait is always applicable, then it's sound to specialize on it. We check trait is always applicable in the same way as impls, except that step 4 is now "all predicates on `impl1` are always applicable". We require that `specialization` or `min_specialization` is enabled to implement these traits.
### rustc_specialization_marker
There are also some specialization on traits with no methods, including the `FusedIterator` trait which is advertised as allowing optimizations. We allow marking marker traits with an unstable attribute that means we ignore them in point 3 of the checks above. This is unsound but we allow it in the short term because it can't cause use after frees with purely safe code in the same way as specializing on traits methods can.
Changes:
````
rustup https://github.com/rust-lang/rust/pull/69738
rustup https://github.com/rust-lang/rust/pull/68944
Make use of `or_patterns` feature
rustup https://github.com/rust-lang/rust/pull/69589/
Rustup to rust-lang/rust#69076
Don't convert Path to lossy str
Use `into_path`
Use pattern matching instead of manually checking condition
Fix typo
Remove git2 dependency.
Document that wildcard_imports doesn't warn about `use ...::prelude::*;`
Change changelog formatting
Update changelog_update doc to reflect the actual ordering of the changelog
Update CHANGELOG.md
````
Dylan DPC [Mon, 16 Mar 2020 12:16:44 +0000 (13:16 +0100)]
Rollup merge of #69989 - petrochenkov:nolegacy, r=eddyb,matthewjasper
resolve/hygiene: `macro_rules` are not "legacy"
The "modern" vs "legacy" naming was introduced by jseyfried during initial implementation of macros 2.0.
At this point it's clear that `macro_rules` are not going anywhere and won't be deprecated in the near future.
So this PR changes the naming "legacy" (when it implies "macro_rules") to "macro_rules".
This should also help people reading this code because it's wasn't obvious that "legacy" actually meant "macro_rules" in these contexts.
The most contentious renaming here is probably
```
fn modern -> fn normalize_to_macros_2_0
fn modern_and_legacy -> fn normalize_to_macro_rules
```
Other alternatives that I could think of are `normalize_to_opaque`/`normalize_to_semitransparent`, or `strip_non_opaque`/`strip_transparent`, but they seemed less intuitive.
The documentation to these functions can be found in `symbol.rs`.
Dylan DPC [Mon, 16 Mar 2020 12:16:35 +0000 (13:16 +0100)]
Rollup merge of #69122 - dtolnay:backtrace, r=cramertj
Backtrace Debug tweaks
- Change Debug representation of disabled and unsupported backtraces to use \<placeholder\> style, same as what we do for debug printing locked mutexes and mutably borrowed refcells;
Dylan DPC [Mon, 16 Mar 2020 12:16:30 +0000 (13:16 +0100)]
Rollup merge of #67335 - ecstatic-morse:qualif-refactor, r=eddyb
Refactor the `Qualif` trait
This PR attempts to preserve the existing semantics of the `Qualif` trait while reducing its API to two significant methods with descriptive names, `in_any_value_of_ty` and `in_adt_inherently`. The other `in_*` methods have been made into free functions, since they should never be overloaded. Finally, I changed the bounds on the `in_local` argument to be less restrictive (`FnMut` instead of `Fn`), which addresses a FIXME in the const-checker.
bors [Mon, 16 Mar 2020 02:52:47 +0000 (02:52 +0000)]
Auto merge of #70034 - Dylan-DPC:rollup-5yg771j, r=Dylan-DPC
Rollup of 8 pull requests
Successful merges:
- #69686 (Use `pprust` to print attributes in rustdoc)
- #69858 (std: on Windows, use GetSystemTimePreciseAsFileTime if it is available)
- #69917 (Cleanup E0412 and E0422)
- #69964 (Add Node.js to PR CI image)
- #69992 (Block version-specific docs from search engines)
- #69995 (Add more context to the literal overflow message)
- #69998 (Add long error explanation for E0634)
- #70014 (Small fixes in rustdoc book)
Dylan DPC [Mon, 16 Mar 2020 00:30:41 +0000 (01:30 +0100)]
Rollup merge of #70014 - TimotheeGerber:small-fix-rustdoc-book, r=Dylan-DPC
Small fixes in rustdoc book
I read the `rustdoc` book today and noticed some small typos/problems. Mainly:
- `# fn foo() {}` was displayed when not needed because fenced block code type was `text` instead of `rust`;
- two path separators were missing and some Windows-style separators were not consistent with the rest of them (mainly Linux-style).
Here are my proposed fixes. It is my first PR for the rust project. Don't hesitate to tell me if I am doing it wrong or if you need anything else.
Dylan DPC [Mon, 16 Mar 2020 00:30:35 +0000 (01:30 +0100)]
Rollup merge of #69992 - kornelski:robots, r=steveklabnik
Block version-specific docs from search engines
Latest stable, beta and nightly URLs remain accessible because their URLs don't start with a version number. Robots.txt uses simple path prefixes, so it's OK that the disallow rules aren't full directory paths.
Direct links to old docs remain accessible to users, because robots.txt only affects crawlers.
With this change old docs for specific old versions of Rust won't pop up in search results. This is good, because users won't be getting obsolete documentation by accident.
I'm not sure what the original motivation was for the `render_attribute`, so I may be missing something, but replacing it with `pprust::attribute_to_string` seems to give the intended output (modulo some spacing idiosyncrasies).
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