Commit Graph

1435 Commits

Author SHA1 Message Date
Dylan DPC
463b6cc0e1
Rollup merge of #78268 - JohnTitor:issue-78262, r=estebank
Do not try to report on closures to avoid ICE

Fixes #78262
2020-10-26 03:09:11 +01:00
Dylan DPC
8646c2a15b
Rollup merge of #78247 - simonvandel:fix-78192, r=oli-obk
Fix #78192

Check which places are marked dead.

Fixes #78192
2020-10-26 03:09:08 +01:00
Dylan DPC
083a5cd9a2
Rollup merge of #78214 - estebank:match-semicolon, r=oli-obk
Tweak match arm semicolon removal suggestion to account for futures

* Tweak and extend "use `.await`" suggestions
* Suggest removal of semicolon on prior match arm
* Account for `impl Future` when suggesting semicolon removal
* Silence some errors when encountering `await foo()?` as can't be certain what the intent was

*Thanks to https://twitter.com/a_hoverbear/status/1318960787105353728 for pointing this out!*
2020-10-26 03:09:06 +01:00
Dylan DPC
147a001fd3
Rollup merge of #78126 - shepmaster:aarch64-apple-darwin-valist, r=nagisa
Properly define va_arg and va_list for aarch64-apple-darwin

From [Apple][]:

> Because of these changes, the type `va_list` is an alias for `char*`,
> and not for the struct type in the generic procedure call standard.

With this change `/x.py test --stage 1 src/test/ui/abi/variadic-ffi`
passes.

Fixes #78092

[Apple]: https://developer.apple.com/documentation/xcode/writing_arm64_code_for_apple_platforms
2020-10-26 03:09:00 +01:00
Jake Goulding
0a91755ff4 Properly define va_arg and va_list for aarch64-apple-darwin
From [Apple][]:

> Because of these changes, the type `va_list` is an alias for `char*`,
> and not for the struct type in the generic procedure call standard.

With this change `/x.py test --stage 1 src/test/ui/abi/variadic-ffi`
passes.

Fixes #78092

[Apple]: https://developer.apple.com/documentation/xcode/writing_arm64_code_for_apple_platforms
2020-10-25 21:37:01 -04:00
bors
4760b8fb88 Auto merge of #78179 - RalfJung:miri-comments, r=oli-obk
Miri engine: entirely skip interning of ZST, and improve some comments

r? `@oli-obk`
2020-10-25 20:15:44 +00:00
bors
f392479de6 Auto merge of #78350 - JohnTitor:rollup-vbbm5wf, r=JohnTitor
Rollup of 8 pull requests

Successful merges:

 - #77984 (Compute proper module parent during resolution)
 - #78085 (MIR validation should check `SwitchInt` values are valid for the type)
 - #78208 (replace `#[allow_internal_unstable]` with `#[rustc_allow_const_fn_unstable]` for `const fn`s)
 - #78209 (Update `compiler_builtins` to 0.1.36)
 - #78276 (Bump backtrace-rs to enable Mach-O support on iOS.)
 - #78320 (Link to cargo's `build-std` feature instead of `xargo` in custom target docs)
 - #78322 (BTreeMap: stop mistaking node::MIN_LEN for a node level constraint)
 - #78326 (Split out statement attributes changes from #78306)

Failed merges:

r? `@ghost`
2020-10-25 11:35:26 +00:00
Yuki Okushi
0a26e4ba7e
Rollup merge of #78326 - Aaron1011:fix/min-stmt-lints, r=petrochenkov
Split out statement attributes changes from #78306

This is the same as PR https://github.com/rust-lang/rust/pull/78306, but `unused_doc_comments` is modified to explicitly ignore statement items (which preserves the current behavior).

This shouldn't have any user-visible effects, so it can be landed without lang team discussion.

---------
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.

```rust
trait Foo {
    #[allow(unused_attributes)] #[inline] fn first();
    #[inline] #[allow(unused_attributes)] fn second();
}
```

However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).

Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.

This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:

* The `HasAttr` impl for `StmtKind` now returns attributes for
  `StmtKind::Item`, treating it just like every other `StmtKind`
  variant. The only place relying on the old behavior was macro
  which has been updated to explicitly ignore attributes on item
  statements. This allows the `unused_doc_comments` lint to fire for
  item statements.
* The `early` and `late` lint visitors now activate lint attributes when
  invoking the callback for `Stmt`. This ensures that a lint
  attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
  sibiling attributes on an item statement.

For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
2020-10-25 18:43:49 +09:00
Yuki Okushi
72e02b015e
Rollup merge of #78208 - liketechnik:issue-69399, r=oli-obk
replace `#[allow_internal_unstable]` with `#[rustc_allow_const_fn_unstable]` for `const fn`s

`#[allow_internal_unstable]` is currently used to side-step feature gate and stability checks.
While it was originally only meant to be used only on macros, its use was expanded to `const fn`s.

This pr adds stricter checks for the usage of `#[allow_internal_unstable]` (only on macros) and introduces the `#[rustc_allow_const_fn_unstable]` attribute for usage on `const fn`s.

This pr does not change any of the functionality associated with the use of `#[allow_internal_unstable]` on macros or the usage of `#[rustc_allow_const_fn_unstable]` (instead of `#[allow_internal_unstable]`) on `const fn`s (see https://github.com/rust-lang/rust/issues/69399#issuecomment-712911540).

Note: The check for `#[rustc_allow_const_fn_unstable]` currently only validates that the attribute is used on a function, because I don't know how I would check if the function is a `const fn` at the place of the check. I therefore openend this as a 'draft pull request'.

Closes rust-lang/rust#69399

r? @oli-obk
2020-10-25 18:43:40 +09:00
Yuki Okushi
dbdc61f9f9
Rollup merge of #78085 - wesleywiser:mir_validation_switch_int, r=oli-obk
MIR validation should check `SwitchInt` values are valid for the type

Fixes #75440
2020-10-25 18:43:38 +09:00
Yuki Okushi
569d29d55c
Rollup merge of #77984 - Aaron1011:fix/macro-mod-weird-parent, r=petrochenkov
Compute proper module parent during resolution

Fixes #75982

The direct parent of a module may not be a module
(e.g. `const _: () =  { #[path = "foo.rs"] mod foo; };`).

To find the parent of a module for purposes of resolution, we need to
walk up the tree until we hit a module or a crate root.
2020-10-25 18:43:37 +09:00
bors
5171cc76c2 Auto merge of #77476 - tgnottingham:buffered_siphasher128, r=nnethercote
perf: buffer SipHasher128

This is an attempt to improve Siphasher128 performance by buffering input. Although it reduces instruction count, I'm not confident the effect on wall times, or lack-thereof, is worth the change.

---

Additional notes not reflected in source comments:

* Implementation choices were guided by a combination of results from rustc-perf and micro-benchmarks, mostly the former.
* ~~I tried a couple of different struct layouts that might be more cache friendly with no obvious effect.~~ Update: a particular struct layout was chosen, but it's not critical to performance. See comments in source and discussion below.
* I suspect that buffering would be important to a SIMD-accelerated algorithm, but from what I've read and my own tests, SipHash does not seem very amenable to SIMD acceleration, at least by SSE.
2020-10-25 09:23:45 +00:00
bors
3e0dd24a6c Auto merge of #77546 - lcnr:impl-trait-closure, r=eddyb
fix def collector for impl trait

fixes #77329

We now consistently make `impl Trait` a hir owner, requiring some special casing for synthetic generic params.

r? `@eddyb`
2020-10-25 07:03:58 +00:00
bors
17cc9b6256 Auto merge of #77398 - wesleywiser:measureme_0_8, r=Mark-Simulacrum
Upgrade to measureme 9.0.0

I believe I did this correctly but there's still a reference to `measureme@0.7.1` coming from `rustc-ap-rustc_data_structures` and I'm not sure how to resolve that.

r? `@Mark-Simulacrum`

We'll also need to deploy the new version of the tools on perf.rlo.
2020-10-25 04:48:37 +00:00
Wesley Wiser
5ac5556d63 Upgrade to measureme 9.0.0 2020-10-24 22:39:42 -04:00
bors
36a74944cb Auto merge of #77526 - RalfJung:dont-promote-unions, r=lcnr
stop promoting union field accesses in 'const'

Turns out that promotion of union field accesses is the only difference between "promotion in `const`/`static` bodies" and "explicit promotion". So if we can remove this, we have finally achieved what I thought to already be the case -- that the bodies of `const`/`static` initializers behave the same as explicit promotion contexts.

The reason we do not want to promote union field accesses is that they can introduce UB, i.e., they can go wrong. We want to [minimize the ways promoteds can fail to evaluate](https://github.com/rust-lang/const-eval/issues/53). Also this change makes things more consistent overall, removing a special case that was added without much consideration (as far as I can tell).

Cc `@rust-lang/wg-const-eval`
2020-10-25 02:27:09 +00:00
Yuki Okushi
7b4c397b73 Do not try to report on closures to avoid ICE 2020-10-25 11:19:49 +09:00
bors
f58ffc9381 Auto merge of #78334 - jonas-schievink:rollup-z0gzbmm, r=jonas-schievink
Rollup of 12 pull requests

Successful merges:

 - #75115 (`#[deny(unsafe_op_in_unsafe_fn)]` in sys/cloudabi)
 - #76614 (change the order of type arguments on ControlFlow)
 - #77610 (revise Hermit's mutex interface to support the behaviour of StaticMutex)
 - #77830 (Simplify query proc-macros)
 - #77930 (Do not ICE with TraitPredicates containing [type error])
 - #78069 (Fix const core::panic!(non_literal_str).)
 - #78072 (Cleanup constant matching in exhaustiveness checking)
 - #78119 (Throw core::panic!("message") as &str instead of String.)
 - #78191 (Introduce a temporary for discriminant value in MatchBranchSimplification)
 - #78272 (const_evaluatable_checked: deal with unused nodes + div)
 - #78318 (TyCtxt: generate single impl block with `slice_interners` macro)
 - #78327 (resolve: Relax macro resolution consistency check to account for any errors)

Failed merges:

r? `@ghost`
2020-10-24 21:42:39 +00:00
Jonas Schievink
58ae889779
Rollup merge of #78327 - petrochenkov:inconsist, r=Aaron1011
resolve: Relax macro resolution consistency check to account for any errors

The check was previously omitted only when ambiguity errors or `Res::Err` were encountered, but the "macro-expanded `extern crate` items cannot shadow..." error (at least) can cause same inconsistencies as well.

Fixes https://github.com/rust-lang/rust/issues/78325
2020-10-24 22:40:00 +02:00
Jonas Schievink
a8ff5a4e03
Rollup merge of #78318 - bugadani:tyctx-impl, r=petrochenkov
TyCtxt: generate single impl block with `slice_interners` macro

Reduces the work needed to check overlapping impls a bit.
2020-10-24 22:39:59 +02:00
Jonas Schievink
5ed8ac45d4
Rollup merge of #78272 - lcnr:abstract-const-unused-node, r=oli-obk
const_evaluatable_checked: deal with unused nodes + div

r? @oli-obk
2020-10-24 22:39:57 +02:00
Jonas Schievink
597b4c5bb4
Rollup merge of #78191 - tmiasko:temp-match-branch-simplification, r=oli-obk
Introduce a temporary for discriminant value in MatchBranchSimplification

The optimization introduces additional uses of the discriminant operand, but
does not ensure that it is still valid to evaluate it or that it still
evaluates to the same value.

Evaluate it once at original position, and store the result in a new temporary.

Follow up on #78151. The optimization remains disabled by default.

Closes #78239.
2020-10-24 22:39:55 +02:00
Jonas Schievink
e12e97223f
Rollup merge of #78072 - Nadrieril:cleanup-constant-matching, r=varkor
Cleanup constant matching in exhaustiveness checking

This supercedes https://github.com/rust-lang/rust/pull/77390. I made the `Opaque` constructor work.
I have opened two issues https://github.com/rust-lang/rust/issues/78071 and https://github.com/rust-lang/rust/issues/78057 from the discussion we had on the previous PR. They are not regressions nor directly related to the current PR so I thought we'd deal with them separately.

I left a FIXME somewhere because I didn't know how to compare string constants for equality. There might even be some unicode things that need to happen there. In the meantime I preserved previous behavior.

EDIT: I accidentally fixed #78071
2020-10-24 22:39:51 +02:00
Jonas Schievink
0a06d7344b
Rollup merge of #78069 - fusion-engineering-forks:core-const-panic-str, r=RalfJung
Fix const core::panic!(non_literal_str).

Invocations of `core::panic!(x)` where `x` is not a string literal expand to `panic!("{}", x)`, which is not understood by the const panic logic right now. This adds `panic_str` as a lang item, and modifies the const eval implementation to hook into this item as well.

This fixes the issue mentioned here: https://github.com/rust-lang/rust/issues/51999#issuecomment-687604248

r? `@RalfJung`

`@rustbot` modify labels: +A-const-eval
2020-10-24 22:39:49 +02:00
Jonas Schievink
7428de1583
Rollup merge of #77930 - estebank:ice-77919, r=eddyb
Do not ICE with TraitPredicates containing [type error]

Fix #77919.
2020-10-24 22:39:47 +02:00
Jonas Schievink
4d72939af1
Rollup merge of #77830 - cjgillot:remacro, r=oli-obk
Simplify query proc-macros

The query code generation is split between proc-macros and regular macros in `rustc_middle::ty::query`.

This PR removes unused capabilities of the proc-macros, and tend to use regular macros for the logic.
2020-10-24 22:39:46 +02:00
Jonas Schievink
a547055184
Rollup merge of #76614 - NoraCodes:nora/control_flow_enum, r=scottmcm
change the order of type arguments on ControlFlow

This allows ControlFlow<BreakType> which is much more ergonomic for common iterator combinator use cases.

Addresses one component of #75744
2020-10-24 22:39:41 +02:00
Wesley Wiser
dd683e5ab5 MIR validation should check SwitchInt values are valid for the type 2020-10-24 16:00:04 -04:00
bors
ffa2e7ae8f Auto merge of #77255 - Aaron1011:feature/collect-attr-tokens, r=petrochenkov
Unconditionally capture tokens for attributes.

This allows us to avoid synthesizing tokens in `prepend_attr`, since we
have the original tokens available.

We still need to synthesize tokens when expanding `cfg_attr`,
but this is an unavoidable consequence of the syntax of `cfg_attr` -
the user does not supply the `#` and `[]` tokens that a `cfg_attr`
expands to.

This is based on PR https://github.com/rust-lang/rust/pull/77250 - this PR exposes a bug in the current `collect_tokens` implementation, which is fixed by the rewrite.
2020-10-24 19:23:32 +00:00
Aaron Hill
283053a742
Compute proper module parent during resolution
Fixes #75982

The direct parent of a module may not be a module
(e.g. `const _: () =  { #[path = "foo.rs"] mod foo; };`).

To find the parent of a module for purposes of resolution, we need to
walk up the tree until we hit a module or a crate root.
2020-10-24 14:28:13 -04:00
Vadim Petrochenkov
ef09ed2002 resolve: Relax macro resolution consistency check to account for any errors 2020-10-24 21:26:08 +03:00
Jake Goulding
c6ab758e54 Switch from tuple matching to match guards 2020-10-24 12:58:38 -04:00
Aaron Hill
ac384ac2db
Fix inconsistencies in handling of inert attributes on statements
When the 'early' and 'late' visitors visit an attribute target, they
activate any lint attributes (e.g. `#[allow]`) that apply to it.
This can affect warnings emitted on sibiling attributes. For example,
the following code does not produce an `unused_attributes` for
`#[inline]`, since the sibiling `#[allow(unused_attributes)]` suppressed
the warning.

```rust
trait Foo {
    #[allow(unused_attributes)] #[inline] fn first();
    #[inline] #[allow(unused_attributes)] fn second();
}
```

However, we do not do this for statements - instead, the lint attributes
only become active when we visit the struct nested inside `StmtKind`
(e.g. `Item`).

Currently, this is difficult to observe due to another issue - the
`HasAttrs` impl for `StmtKind` ignores attributes for `StmtKind::Item`.
As a result, the `unused_doc_comments` lint will never see attributes on
item statements.

This commit makes two interrelated fixes to the handling of inert
(non-proc-macro) attributes on statements:

* The `HasAttr` impl for `StmtKind` now returns attributes for
  `StmtKind::Item`, treating it just like every other `StmtKind`
  variant. The only place relying on the old behavior was macro
  which has been updated to explicitly ignore attributes on item
  statements. This allows the `unused_doc_comments` lint to fire for
  item statements.
* The `early` and `late` lint visitors now activate lint attributes when
  invoking the callback for `Stmt`. This ensures that a lint
  attribute (e.g. `#[allow(unused_doc_comments)]`) can be applied to
  sibiling attributes on an item statement.

For now, the `unused_doc_comments` lint is explicitly disabled on item
statements, which preserves the current behavior. The exact locatiosn
where this lint should fire are being discussed in PR #78306
2020-10-24 11:55:48 -04:00
Jonas Schievink
1ac137be93
Rollup merge of #78307 - rust-lang:revert-77961-embed-bitcode, r=tmandry
Revert "Set .llvmbc and .llvmcmd sections as allocatable"

Reverts rust-lang/rust#77961, see discussion starting from https://github.com/rust-lang/rust/pull/77961#issuecomment-712313902
2020-10-24 14:12:20 +02:00
Jonas Schievink
da486467d4
Rollup merge of #78300 - richkadel:coverage-cx, r=wesleywiser
Make codegen coverage_context optional, and check

Addresses Issue #78286

Libraries compiled with coverage and linked with out enabling coverage
would fail when attempting to add the library's coverage statements to
the codegen coverage context (None).

Now, if coverage statements are encountered while compiling / linking
with `-Z instrument-coverage` disabled, codegen will *not* attempt to
add code regions to a coverage map, and it will not inject the LLVM
instrprof_increment intrinsic calls.
2020-10-24 14:12:18 +02:00
Jonas Schievink
2362659b00
Rollup merge of #78292 - bugadani:recursion, r=nagisa
Loop instead of recursion

I saw the comment `// FIXME: consider not using recursion to lower this.` and considered not using recursion :)
2020-10-24 14:12:15 +02:00
Jonas Schievink
b6ae1fabee
Rollup merge of #78278 - lcnr:predicate-visit, r=matthewjasper
move `visit_predicate` into `TypeVisitor`

Seems easier than dealing with `PredicateVisitor` for me which I needed for object safety checks for `PredicateAtom::ConstEvaluatable`. Is there a reason I am missing for this split?

r? @matthewjasper
2020-10-24 14:12:13 +02:00
Jonas Schievink
77cd5b5485
Rollup merge of #78249 - lcnr:ct-infer-origin, r=varkor
improve const infer error

For type inference we probably have to be careful about subtyping and stuff but considering that subtyping shouldn't be relevant for constants I don't really see a reason why we may not want to reuse the const origin here.

r? `@varkor`
2020-10-24 14:12:06 +02:00
Jonas Schievink
86c07a4955
Rollup merge of #78198 - tmiasko:assert, r=davidtwco
Simplify assert terminator only if condition evaluates to expected value
2020-10-24 14:12:03 +02:00
Jonas Schievink
fb92b70f95
Rollup merge of #77716 - francesca64:revert-ios-dynamic-linking, r=jonas-schievink
Revert "Allow dynamic linking for iOS/tvOS targets."

This reverts PR #73516.

On macOS I compile static libs for iOS, automated using [cargo-mobile](https://github.com/BrainiumLLC/cargo-mobile), which has worked smoothly for the past 2 years. However, upon updating to Rust 1.46.0, I was no longer able to use Rust on iOS. I've bisected this to the PR referenced above.

For most projects tested, apps now immediately crash with a message like this:
```
dyld: Library not loaded: /Users/francesca/Projects/example/target/aarch64-apple-ios/debug/deps/libexample.dylib
  Referenced from: /private/var/containers/Bundle/Application/745912AF-A928-465C-B340-872BD1C9F368/example.app/example
  Reason: image not found
dyld: launch, loading dependent libraries
DYLD_LIBRARY_PATH=/usr/lib/system/introspection
DYLD_INSERT_LIBRARIES=/Developer/usr/lib/libBacktraceRecording.dylib:/Developer/usr/lib/libMainThreadChecker.dylib:/Developer/Library/PrivateFrameworks/DTDDISupport.framework/libViewDebuggerSupport.dylib:/Developer/Library/PrivateFrameworks/GPUTools.framework/libglInterpose.dylib:/usr/lib/libMTLCapture.dylib
```

This can be reproduced by using cargo-mobile to generate a winit example project, and then attempting to run it on an iOS device (`cargo mobile init && cargo apple open`).

In our projects that depend on DisplayLink, the build instead fails with a linker error:
```
= note: Undefined symbols for architecture arm64:
            "_CACurrentMediaTime", referenced from:
                display_link::ios::run_callback_ios10::hda81197ff46aedbd in libapp-4f0abc1d7684103f.rlib(app-4f0abc1d7684103f.40d4iro0yz1iy487.rcgu.o)
                display_link::ios::run_callback_pre_ios10::h91f085da19374320 in libapp-4f0abc1d7684103f.rlib(app-4f0abc1d7684103f.40d4iro0yz1iy487.rcgu.o)
          ld: symbol(s) not found for architecture arm64
```

After reverting the change to enable dynamic linking on iOS, everything works the same as it did on Rust 1.45.2 for me.

In the future, would it be possible for me to be pinged when iOS-related PRs are made? I work for a company that intends on using Rust on iOS in production, so I'd gladly provide testing.

cc @aspenluxxxy
2020-10-24 14:11:59 +02:00
Dániel Buga
6533d010cf Don't generate multiple impl blocks 2020-10-24 11:55:00 +02:00
Dániel Buga
f88d6e8437 Loop instead of recursion 2020-10-24 01:24:58 +02:00
Rich Kadel
f75a236fe0
Update compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
Co-authored-by: Wesley Wiser <wwiser@gmail.com>
2020-10-23 14:58:08 -07:00
Tyler Mandry
6640a62e0e
Revert "Set .llvmbc and .llvmcmd sections as allocatable" 2020-10-23 12:54:00 -07:00
Esteban Küber
f71e9ed7f1 review comments 2020-10-23 12:51:06 -07:00
Esteban Küber
b334eef162 Do not ICE with TraitPredicates containing [type error]
Fix #77919.
2020-10-23 12:21:47 -07:00
Rich Kadel
a7bc1a2edf Make codegen coverage_context optional, and check
Addresses Issue #78286

Libraries compiled with coverage and linked with out enabling coverage
would fail when attempting to add the library's coverage statements to
the codegen coverage context (None).

Now, if coverage statements are encountered while compiling / linking
with `-Z instrument-coverage` disabled, codegen will *not* attempt to
add code regions to a coverage map, and it will not inject the LLVM
instrprof_increment intrinsic calls.
2020-10-23 12:00:30 -07:00
bors
7bade6ef73 Auto merge of #77015 - davidtwco:check-attr-variant-closure-expr, r=lcnr
passes: `check_attr` on more targets

This PR modifies `check_attr` so that:

- Enum variants are now checked (some attributes would not have been prohibited on variants previously).
- `check_expr_attributes` and `check_stmt_attributes` are removed as `check_attributes` can perform the same checks. This means that codegen attribute errors aren't shown if there are other errors first (e.g. from other attributes, as shown in `src/test/ui/macros/issue-68060.rs` changes below).
2020-10-23 17:32:04 +00:00
Florian Warzecha
ac2c599f23
fix validation for rustc_allow_const_fn_unstable targets
The validation was introduced in 3a63bf0299
without strict validation of functions, e. g. all function types were
allowed.
Now the validation only allows `const fn`s.
2020-10-23 17:54:48 +02:00
Florian Warzecha
13b481b247
rename allow_internal_unstable() to rustc_allow_const_fn_unstable() in rustc_mir
Followup rename from 05f4a9a42a,
which introduced `#[rustc_allow_const_fn_unstable]` for `const fn`s.
2020-10-23 17:14:57 +02:00