bors [Tue, 22 Dec 2020 21:51:04 +0000 (21:51 +0000)]
Auto merge of #80242 - Nadrieril:explain-and-factor-splitting, r=varkor
Clarify constructor splitting in exhaustiveness checking
I reworked the explanation of the algorithm completely to make it properly account for the various extensions we've added. This includes constructor splitting, which was previously not clearly included in the algorithm. This makes wildcards less magical; I added some detailed examples; and this distinguishes clearly between constructors that only make sense in patterns (like ranges) and those that make sense for values (like `Some`). This reformulation had been floating around in my mind for a while, and I'm quite happy with how it turned out. Let me know how you feel about it.
I also factored out all three cases of splitting (wildcards, ranges and slices) into dedicated structs to encapsulate the complicated bits.
I measured no perf impact but I don't trust my local measurements for refactors since https://github.com/rust-lang/rust/pull/79284.
bors [Tue, 22 Dec 2020 19:02:28 +0000 (19:02 +0000)]
Auto merge of #80177 - tgnottingham:foreign_defpathhash_registration, r=Aaron1011
rustc_query_system: explicitly register reused dep nodes
Register nodes that we've reused from the previous session explicitly
with `OnDiskCache`. Previously, we relied on this happening as a side
effect of accessing the nodes in the `PreviousDepGraph`. For the sake of
performance and avoiding unintended side effects, register explictily.
bors [Tue, 22 Dec 2020 16:09:59 +0000 (16:09 +0000)]
Auto merge of #80071 - jyn514:timings, r=Mark-Simulacrum
Add more timing info to rustdoc
This helped me confirm in https://github.com/rust-lang/rust/issues/79103#issuecomment-745737864 that get_blanket_impls is indeed what's taking all the time on stm32.
bors [Tue, 22 Dec 2020 13:19:40 +0000 (13:19 +0000)]
Auto merge of #79451 - usbalbin:array_zip, r=m-ou-se
Added [T; N]::zip()
This is my first PR to rust so I hope I have done everything right, or at least close :)
---
This is PR adds the array method `[T; N]::zip()` which, in my mind, is a natural extension to #75212.
My implementation of `zip()` is mostly just a modified copy-paste of `map()`. Should I keep the comments? Also am I right in assuming there should be no way for the `for`-loop to panic, thus no need for the dropguard seen in the `map()`-function?
The doc comment is in a similar way a slightly modified copy paste of [`Iterator::zip()`](https://doc.rust-lang.org/beta/std/iter/trait.Iterator.html#method.zip)
`@jplatte` mentioned in [#75490](https://github.com/rust-lang/rust/pull/75490#issuecomment-677790758) `zip_with()`,
> zip and zip_with seem like they would be useful :)
is this something I should add (assuming there is interest for this PR at all :))
bors [Tue, 22 Dec 2020 00:20:14 +0000 (00:20 +0000)]
Auto merge of #80208 - bugadani:generics-of-alloc, r=matthewjasper
Reserve necessary space for params in generics_of
Always reserve space for the exact number of generic parameters we need in generics_of. As far as I can see, the default is 0/4 elements based on has_self, and the vector grows on after that.
bors [Mon, 21 Dec 2020 13:12:36 +0000 (13:12 +0000)]
Auto merge of #79270 - RalfJung:array-repeat-consts, r=oli-obk
Acknowledge that `[CONST; N]` is stable
When `const_in_array_repeat_expressions` (RFC 2203) got unstably implemented as part of https://github.com/rust-lang/rust/pull/61749, accidentally, the special case of repeating a *constant* got stabilized immediately. That is why the following code works on stable:
In contrast, if we had written `[expr; 2]` for some expression that is not *literally* a constant but could be evaluated at compile-time (e.g. `(EMPTY,).0`), this would have failed.
We could take back this stabilization as it was clearly accidental. However, I propose we instead just officially accept this and stabilize a small subset of RFC 2203, while leaving the more complex case of general expressions that could be evaluated at compile-time unstable. Making that case work well is pretty much blocked on inline `const` expressions (to avoid relying too much on [implicit promotion](https://github.com/rust-lang/const-eval/blob/master/promotion.md)), so it could take a bit until it comes to full fruition. `[CONST; N]` is an uncontroversial subset of this feature that has no semantic ambiguities, does not rely on promotion, and basically provides the full expressive power of RFC 2203 but without the convenience (people have to define constants to repeat them, possibly using associated consts if generics are involved).
Well, I said "no semantic ambiguities", that is only almost true... the one point I am not sure about is `[CONST; 0]`. There are two possible behaviors here: either this is equivalent to `let x = CONST; [x; 0]`, or it is a NOP (if we argue that the constant is never actually instantiated). The difference between the two is that if `CONST` has a destructor, it should run in the former case (but currently doesn't, due to https://github.com/rust-lang/rust/issues/74836); but should not run if it is considered a NOP. For regular `[x; 0]` there seems to be consensus on running drop (there isn't really an alternative); any opinions for the `CONST` special case? Should this instantiate the const only to immediately run its destructors? That seems somewhat silly to me. After all, the `let`-expansion does *not* work in general, for `N > 1`.
Cc `@rust-lang/lang` `@rust-lang/wg-const-eval`
Cc https://github.com/rust-lang/rust/issues/49147
bors [Mon, 21 Dec 2020 10:21:01 +0000 (10:21 +0000)]
Auto merge of #80205 - tomprogrammer:prettyprint-pattern-mut-binding, r=davidtwco
Fix pretty printing an AST representing `&(mut ident)`
The PR fixes a misguiding help diagnostic in the parser that I reported in #80186. I discovered that the parsers recovery and reporting logic was correct but the pretty printer produced wrong code for the example. (Details in https://github.com/rust-lang/rust/issues/80186#issuecomment-748498676)
which I think should behave like the original pattern.
Old diagnostic:
```
error: `mut` must be attached to each individual binding
--> src/main.rs:3:9
|
3 | let mut &x = &0;
| ^^^^^^ help: add `mut` to each binding: `&mut x`
|
= note: `mut` may be followed by `variable` and `variable @ pattern`
```
New diagnostic:
```
error: `mut` must be attached to each individual binding
--> src/main.rs:3:9
|
3 | let mut &x = &0;
| ^^^^^^ help: add `mut` to each binding: `&(mut x)`
|
= note: `mut` may be followed by `variable` and `variable @ pattern`
```
Dylan DPC [Mon, 21 Dec 2020 01:47:50 +0000 (02:47 +0100)]
Rollup merge of #80244 - jyn514:spans, r=bugadani
Cleanup markdown span handling
1. Get rid of `locate()` in markdown handling
This function was unfortunate for several reasons:
- It used `unsafe` because it wanted to tell whether a string came from
the same *allocation* as another, not just whether it was a textual match.
- It recalculated spans even though they were already available from pulldown
- It sometimes *failed* to calculate the span, which meant it was always possible for the span to be `None`, even though in practice that should never happen.
This has several cleanups:
- Make the span required
- Pass through the span from pulldown in the `HeadingLinks` and `Footnotes` iterators
- Only add iterator bounds on the `impl Iterator`, not on `new` and the struct itself.
2. Remove unnecessary scope in `markdown_links`
I recommend reading a single commit at a time.
cc ``@bugadani`` - this will conflict with https://github.com/rust-lang/rust/pull/77859, I'll try to make sure that gets merged first.
Dylan DPC [Mon, 21 Dec 2020 01:47:44 +0000 (02:47 +0100)]
Rollup merge of #80211 - wabain:async-fn-trait-bound-suggestion, r=petrochenkov
Handle desugaring in impl trait bound suggestion
Fixes #79843.
When an associated type of a generic function parameter needs extra bounds, the diagnostics may suggest replacing an `impl Trait` with a named type parameter so that it can be referenced in the where clause. On stable and nightly, the suggestion can be malformed, for instance transforming:
```rust
async fn run(_: &, F: Foo(), foo: F) -> std::io::Result<()> where <F as Foo>::Bar: Send
^^^^^^^^ ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
Where we want something like:
```rust
async fn run<F: Foo>(_: &(), foo: F) -> std::io::Result<()> where <F as Foo>::Bar: Send
^^^^^^^^ ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
The problem is that the elided lifetime of `&()` is added as a generic parameter when desugaring the async fn; the suggestion code sees this as an existing generic parameter and tries to use its span as an anchor to inject `F` into the parameter list. There doesn't seem to be an entirely principled way to check which generic parameters in the HIR were explicitly named in the source, so this commit changes the heuristics when generating the suggestion to only consider type parameters whose spans are contained within the span of the `Generics` when determining how to insert an additional type parameter into the declaration. (And to be safe it also excludes parameters whose spans are marked as originating from desugaring, although that doesn't seem to handle this elided lifetime.)
Dylan DPC [Mon, 21 Dec 2020 01:47:33 +0000 (02:47 +0100)]
Rollup merge of #80159 - jyn514:array, r=m-ou-se
Add array search aliases
Missed this in https://github.com/rust-lang/rust/pull/80068. This one will really fix https://github.com/rust-lang/rust/issues/46075.
The last alias especially I'm a little unsure about - maybe fuzzy search should be fixed in rustdoc instead? Happy to make that change although I'd have to figure out how.
r? ``@m-ou-se`` although cc ``@GuillaumeGomez`` for the search issue.
bors [Mon, 21 Dec 2020 01:16:20 +0000 (01:16 +0000)]
Auto merge of #80088 - operutka:fix-cmsg-len-uclibc, r=dtolnay
Fix failing build of std on armv5te-unknown-linux-uclibceabi due to missing cmsg_len_zero
I'm getting the following error when trying to build `std` on `armv5te-unknown-linux-uclibceabi`:
```
error[E0425]: cannot find value `cmsg_len_zero` in this scope
--> /home/operutka/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys/unix/ext/net/ancillary.rs:376:47
|
376 | let data_len = (*cmsg).cmsg_len - cmsg_len_zero;
| ^^^^^^^^^^^^^ not found in this scope
```
Obviously, this branch:
```rust
cfg_if::cfg_if! {
if #[cfg(any(target_os = "android", all(target_os = "linux", target_env = "gnu")))] {
let cmsg_len_zero = libc::CMSG_LEN(0) as libc::size_t;
} else if #[cfg(any(
target_os = "dragonfly",
target_os = "emscripten",
target_os = "freebsd",
all(target_os = "linux", target_env = "musl",),
target_os = "netbsd",
target_os = "openbsd",
))] {
let cmsg_len_zero = libc::CMSG_LEN(0) as libc::socklen_t;
}
}
```
does not cover the case `all(target_os = "linux", target_env = "uclibc")`.
Joshua Nelson [Sun, 20 Dec 2020 19:28:20 +0000 (14:28 -0500)]
Get rid of `locate()` in markdown handling
This function was unfortunate for several reasons:
- It used `unsafe` because it wanted to tell whether a string came from
the same *allocation* as another, not just whether it was a textual
match.
- It recalculated spans even though they were already available from
pulldown
- It sometimes *failed* to calculate the span, which meant it was always
possible for the span to be `None`, even though in practice that
should never happen.
This commit has several cleanups:
- Make the span required
- Pass through the span from pulldown in the `HeadingLinks` and
`Footnotes` iterators
- Only add iterator bounds on the `impl Iterator`, not on `new` and the
struct itself.
The compiler would be very slow at processing it, because
an internal algorithm would run in O(n^2), where n is the number
of impl blocks. Now, we add a new algorithm that allocates but
is faster asymptotically.
Comparing rustc nightly with a local build of rustc as of this PR (results in seconds):
| N | real time before | real time after |
| - | - | - |
| 4_000 | 0.57 | 0.46 |
| 8_000 | 1.31 | 0.84 |
| 16_000 | 3.56 | 1.69 |
| 32_000 | 10.60 | 3.73 |
I've tuned up the numbers to make the effect larger than the startup noise of rustc, but the asymptotic difference should hold for smaller n as well.
Note: current state of the PR omits error messages if there are other errors present already. For now, I'm mainly interested in a perf run to study whether this issue is present at all. Please queue one for this PR. Thanks!
bors [Sun, 20 Dec 2020 16:36:23 +0000 (16:36 +0000)]
Auto merge of #74699 - notriddle:fd-non-negative, r=m-ou-se
Mark `-1` as an available niche for file descriptors
Based on discussion from <https://internals.rust-lang.org/t/can-the-standard-library-shrink-option-file/12768>, the file descriptor `-1` is chosen based on the POSIX API designs that use it as a sentinel to report errors. A bigger niche could've been chosen, particularly on Linux, but would not necessarily be portable.
This PR also adds a test case to ensure that the -1 niche (which is kind of hacky and has no obvious test case) works correctly. It requires the "upper" bound, which is actually -1, to be expressed in two's complement.
bors [Sun, 20 Dec 2020 13:47:23 +0000 (13:47 +0000)]
Auto merge of #80213 - jryans:bootstrap-skip-dsymutil, r=nagisa
Skip `dsymutil` by default for compiler bootstrap
`dsymutil` adds time to builds on Apple platforms for no clear benefit, and also makes it more difficult for debuggers to find debug info (which `@pnkfelix` highlighted on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/does.20lldb.20%28or.20gdb%29.20work.20on.20rustc.20on.20Mac.3F/near/220482092)). The compiler currently defaults to running `dsymutil` to preserve its historical default, but when compiling the compiler itself, we skip it by default since we know it's safe to do so in that case.
Thomas Bahn [Sat, 19 Dec 2020 22:13:50 +0000 (23:13 +0100)]
Fix pretty printing an AST representing `&(mut ident)`
`PatKind::Ref(PatKind::Ident(BindingMode::ByValue(Mutability::Mut), ..), ..)`
is an AST representing `&(mut ident)`. It was errorneously printed as
`&mut ident` which reparsed into a syntactically different AST.
This PR implements the edition-specific behavior of `:pat` wrt or-patterns, as determined by the crater runs and T-lang consensus in https://github.com/rust-lang/rust/issues/54883#issuecomment-745509090.
I believe this can unblock stabilization of or_patterns.
J. Ryan Stinnett [Sun, 20 Dec 2020 02:49:18 +0000 (02:49 +0000)]
Skip `dsymutil` by default for compiler bootstrap
`dsymutil` adds time to builds on Apple platforms for no clear benefit, and also
makes it more difficult for debuggers to find debug info. The compiler currently
defaults to running `dsymutil` to preserve its historical default, but when
compiling the compiler itself, we skip it by default since we know it's safe to
do so in that case.
bors [Sun, 20 Dec 2020 00:50:46 +0000 (00:50 +0000)]
Auto merge of #79635 - lcnr:const-eval-idk, r=oli-obk
const_evaluatable_checked: fix occurs check
fixes #79615
this is kind of a hack because we use `TypeRelation` for both the `Generalizer` and the `ConstInferUnifier` but i am not sure if there is a useful way to disentangle this without unnecessarily duplicating some code.
The error in the added test is kind of unavoidable until we erase the unused substs of `ConstKind::Unevaluated`. We talked a bit about this in the cg lazy norm meeting (https://rust-lang.zulipchat.com/#narrow/stream/260443-project-const-generics/topic/lazy_normalization_consts)
bors [Sat, 19 Dec 2020 22:01:45 +0000 (22:01 +0000)]
Auto merge of #6477 - xFrednet:0000-enable-search-with-dashes, r=ebroto
Adapted the website search for better matching
* This adds the ability to search for ids with dashes and spaces in the name.
* Example: `missing-errors-doc` and `missing errors doc` are now valid aliases for lint names
* It also improves the fuzzy search in the description. This search will now match any lint that where all searched words are inside the description.
* Example: `doc section` finds two lints in our selection
This was suggested/discussed on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/257328-clippy/topic/Enable.20lint.20search.20with.20dashes/near/220469464)
### Testing
These changes can be tested locally by:
1. Clone this branch
2. Download the current lint index from the [gh-pages branch](https://github.com/rust-lang/rust-clippy/blob/gh-pages/master/lints.json)
3. Put it next to the `util/gh-pages/index.html` and open the html file. Make sure that it can load the lint data. (Browsers can be a bit iffy when opening a loacl html page and loading data)
### Note
I found that searching only a few characters (< 3) seams slow and deleting one even more as almost every lint description contains them. This also happens in our current [lint list](https://rust-lang.github.io/rust-clippy/master/index.html). We could change the search to only be triggered if the search field contains more than 3 letters to slightly improve performance.
---
changelog: Adapted the website search for better matching
bors [Sat, 19 Dec 2020 21:57:38 +0000 (21:57 +0000)]
Auto merge of #79473 - m-ou-se:clamp-in-core, r=m-ou-se
Move {f32,f64}::clamp to core.
`clamp` was recently stabilized (tracking issue: https://github.com/rust-lang/rust/issues/44095). But although `Ord::clamp` was added in `core` (because `Ord` is in `core`), the versions for the `f32` and `f64` primitives were added in `std` (together with `floor`, `sin`, etc.), not in `core` (together with `min`, `max`, `from_bits`, etc.).
This change moves them to `core`, such that `clamp` on floats is available in `no_std` programs as well.
bors [Sat, 19 Dec 2020 21:39:19 +0000 (21:39 +0000)]
Auto merge of #6316 - ThibsG:WrongSelfConventionTraitDef, r=ebroto
Lint also in trait def for `wrong_self_convention`
Extends `wrong_self_convention` to lint also in trait definition.
By the way, I think the `wrong_pub_self_convention` [example](https://github.com/rust-lang/rust-clippy/blob/dd826b4626c00da53f76f00f02f03556803e9cdb/clippy_lints/src/methods/mod.rs#L197) is misleading.
On [playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=32615ab3f6009e7e42cc3754be0ca17f), it fires `wrong_self_convention`, so the example (or the lint maybe?) needs to be reworked.
The difference with `wrong_self_convention` [example](https://github.com/rust-lang/rust-clippy/blob/dd826b4626c00da53f76f00f02f03556803e9cdb/clippy_lints/src/methods/mod.rs#L172) is mainly the `pub` keyword on the method `as_str`, but the lint doesn't use the function visibility as condition to choose which lint to fire (in fact it uses the visibility of the impl item).
fixes: #6307
changelog: Lint `wrong_self_convention` lint in trait def also
bors [Sat, 19 Dec 2020 19:14:04 +0000 (19:14 +0000)]
Auto merge of #80104 - Nadrieril:usefulness-merging, r=varkor
Improve and fix diagnostics of exhaustiveness checking
Primarily, this fixes https://github.com/rust-lang/rust/issues/56379. This also fixes incorrect interactions between or-patterns and slice patterns that I discovered while working on #56379. Those two examples show the incorrect diagnostics:
```rust
match &[][..] {
[true] => {}
[true // detected as unreachable but that's not true
| false, ..] => {}
_ => {}
}
match (true, None) {
(true, Some(_)) => {}
(false, Some(true)) => {}
(true | false, None | Some(true // should be detected as unreachable
| false)) => {}
}
```
I did not measure any perf impact. However, I suspect that [`616ba9f`](https://github.com/rust-lang/rust/pull/80104/commits/616ba9f9f7f5845777a36e1a41a515e6c33a8776) should have a negative impact on large or-patterns. I'll see what the perf run says; I have optimization ideas up my sleeve if needed.
EDIT: I initially had a noticeable perf impact that I thought unavoidable. I then proceeded to avoid it x)
## Motivation
The ip methods seem like prime candidates to be made const: their behavior is defined by an external spec, and based solely on the byte contents of an address. These methods have been made unstable const in the beginning of September, after the necessary const integer arithmetic was stabilized.
There is currently a PR open (#78802) to change the internal representation of `IpAddr{4,6}` from `libc` types to a byte array. This does not have any impact on the constness of the methods.
## Implementation
Most of the stabilizations are straightforward, with the exception of `Ipv6Addr::segments`, which uses the unstable feature `const_fn_transmute`. The code could be rewritten to equivalent stable code, but this leads to worse code generation (#75085).
This is why `segments` gets marked with `#[rustc_allow_const_fn_unstable(const_fn_transmute)]`, like the already const-stable `Ipv6Addr::new`, the justification being that a const-stable alternative implementation exists https://github.com/rust-lang/rust/pull/76206#issuecomment-685044184.
## Future posibilities
This PR const-stabilizes all currently stable ip methods, however there are also a number of unstable methods under the `ip` feature (#27709). These methods are already unstable const. There is a PR open (#76098) to stabilize those methods, which could include const-stabilization. However, stabilizing those methods as const is dependent on `Ipv4Addr::octets` and `Ipv6Addr::segments` (covered by this PR).
bors [Sat, 19 Dec 2020 12:28:00 +0000 (12:28 +0000)]
Auto merge of #6471 - phansch:fix-bless, r=flip1995
Fix blessing of new reference files
Adding of new reference files wasn't handled correctly. It was trying to
read a file that didn't exist yet.
Instead of unwrapping, we now treat a missing reference file as empty
(`Vec::new`). This makes the following conditional work. We then also
have to re-read the reference file after it was being copied. This
second read is technically the same as in the old shell script, but
wasn't really obvious there. The shell script did a `-s` test which
reads the file as well.
changelog: internal: Fix `cargo dev bless` when new reference files are added
Philipp Hansch [Sat, 19 Dec 2020 07:25:42 +0000 (08:25 +0100)]
Fix blessing of new reference files
Adding of new reference files wasn't handled correctly. It was trying to
read a file that didn't exist yet.
Instead of unwrapping, we now treat a missing reference file as empty
(`Vec::new`). This makes the following conditional work. We then also
have to re-read the reference file after it was being copied. This
second read is technically the same as in the old shell script, but
wasn't really obvious. The shell script did a `-s` test which reads the
file.
bors [Sat, 19 Dec 2020 07:23:41 +0000 (07:23 +0000)]
Auto merge of #80180 - JohnTitor:rollup-a31s996, r=JohnTitor
Rollup of 7 pull requests
Successful merges:
- #78083 (Stabilize or_insert_with_key)
- #79211 (Add the "async" and "promise" doc aliases to `core::future::Future`)
- #79612 (Switch some links in compiler/ to intra-doc links)
- #80068 (Add `&mut` as an alias for 'reference' primitive)
- #80129 (docs: Edit rustc_ast::token::Token)
- #80133 (Suppress `CONST_ITEM_MUTATION` lint if a dereference occurs anywhere)
- #80155 (Fix typo)