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2021-06-24Add a "raw" option for asm! which ignores format string specifiersAmanieu d'Antras-22/+29
2021-06-02Auto merge of #85687 - m-ou-se:new-prelude, r=yaahcbors-0/+7
New prelude RFC: rust-lang/rfcs#3114 Tracking issue: https://github.com/rust-lang/rust/issues/85684
2021-06-01Auto merge of #85331 - cjgillot:dirty-dancing, r=Aaron1011bors-686/+500
Make rustc_dirty/clean annotations exhaustive by default Fixes #45009
2021-06-01Auto merge of #85829 - bjorn3:simplify_crate_num, r=jackh726bors-5/+5
Remove CrateNum::ReservedForIncrCompCache It's only use is easily replaceable with `Option<CrateNum>`.
2021-06-01Fix testbjorn3-5/+5
2021-06-01Auto merge of #85886 - GuillaumeGomez:rollup-l3yr3np, r=GuillaumeGomezbors-44/+60
Rollup of 4 pull requests Successful merges: - #85473 (fix split-debuginfo error message) - #85622 (Remove toggle for "undocumented items.") - #85826 (Mention "null pointer optimization" in option docs.) - #85860 (Fix details rustdoc toggle for blanket impl) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
2021-06-01Rollup merge of #85622 - jsha:untoggle-undocumented, r=GuillaumeGomezGuillaume Gomez-44/+60
Remove toggle for "undocumented items." Per discussion in #84326. For trait implementations, this was misleading: the items actually do have documentation (but it comes from the trait definition). For both trait implementations and trait implementors, this was redundant: in both of those cases, the items are default-hidden by different toggle at the level above. Update tests: Remove XPath selectors that over-specified on details tag, in cases that weren't testing toggles. Add an explicit test for toggles on methods. Rename item-hide-threshold to toggle-item-contents for consistency. Demo: https://hoffman-andrews.com/rust/untoggle-undocumented/std/string/struct.String.html https://hoffman-andrews.com/rust/untoggle-undocumented/std/io/trait.Read.html
2021-06-01Revert "Reduce the amount of untracked state in TyCtxt"Camille Gillot-16/+16
2021-06-01Auto merge of #85153 - cjgillot:qresolve, r=Aaron1011bors-16/+16
Reduce the amount of untracked state in TyCtxt Access to untracked global state may generate instances of #84970. The GlobalCtxt contains the lowered HIR, the resolver outputs and interners. By wrapping the resolver inside a query, we make sure those accesses are properly tracked. As a no_hash query, all dependent queries essentially become `eval_always`, what they should have been from the beginning.
2021-05-31Auto merge of #85702 - Aaron1011:no-vec-sort, r=michaelwoeristerbors-0/+15
Don't sort a `Vec` before computing its `DepTrackingHash` Previously, we sorted the vec prior to hashing, making the hash independent of the original (command-line argument) order. However, the original vec was still always kept in the original order, so we were relying on the rest of the compiler always working with it in an 'order-independent' way. This assumption was not being upheld by the `native_libraries` query - the order of the entires in its result depends on the order of entries in `Options.libs`. This lead to an 'unstable fingerprint' ICE when the `-l` arguments were re-ordered. This PR removes the sorting logic entirely. Re-ordering command-line arguments (without adding/removing/changing any arguments) seems like a really niche use case, and correctly optimizing for it would require additional work. By always hashing arguments in their original order, we can entirely avoid a cause of 'unstable fingerprint' errors.
2021-05-31Auto merge of #85704 - Aaron1011:const-panic-hard-err, r=RalfJungbors-128/+56
Emit a hard error when a panic occurs during const-eval Previous, a panic during const evaluation would go through the `const_err` lint. This PR ensures that such a panic always causes compilation to fail.
2021-05-31Auto merge of #85395 - 12101111:build-crt, r=petrochenkovbors-0/+32
Build crtbegin.o/crtend.o from source code Build crtbengin.o/crtend.o from source code instead of copying from gcc. The crtbegin and crtend implementation from llvm don't need `crtbeginS.o` for PIC. `crtbegin{,S,T}.o` is unified into one generic `crtbegin.o`. See the comments in https://reviews.llvm.org/D28791#1419436 and https://reviews.llvm.org/D28791#1420914 fix: https://github.com/rust-lang/rust/issues/85310 , fix: https://github.com/rust-lang/rust/issues/47551 , fix: https://github.com/rust-lang/rust/issues/84033
2021-05-30Remove toggle for "undocumented items."Jacob Hoffman-Andrews-44/+60
Per discussion in #84326. For trait implementations, this was misleading: the items actually do have documentation (but it comes from the trait definition). For both trait implementations and trait implementors, this was redundant: in both of those cases, the items are default-hidden by different toggle at the level above. Update tests: Remove XPath selectors that over-specified on details tag, in cases that weren't testing toggles. Add an explicit test for toggles on methods. Rename item-hide-threshold to toggle-item-contents for consistency.
2021-05-31Build crtbengin.o/crtend.o from source code12101111-0/+32
2021-05-31Auto merge of #85597 - 0yoyoyo:fix-issue-71563-remove-redundant-args, ↵bors-93/+237
r=petrochenkov Fix span of redundant generic arguments Fixes #71563 Above issue is about lifetime arguments, but generic arguments also have same problem. This PR fixes both help messages.
2021-05-30Auto merge of #85559 - 12101111:sanitizer-crt-static, r=nagisabors-0/+9
Diagnose use sanitizers with crt-static Fix: https://github.com/rust-lang/rust/issues/85459
2021-05-30Auto merge of #85838 - GuillaumeGomez:rollup-rk2rh7m, r=GuillaumeGomezbors-22/+66
Rollup of 8 pull requests Successful merges: - #85285 (Add eslint checks to CI) - #85709 (Use correct edition when parsing `:pat` matchers) - #85762 (Do not try to build LLVM with Zlib on Windows) - #85770 (Remove `--print unversioned-files` from rustdoc ) - #85781 (Add documentation for aarch64-apple-ios-sim target) - #85801 (Add `String::extend_from_within`) - #85817 (Fix a typo) - #85818 (Don't drop `PResult` without handling the error) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
2021-05-30Rollup merge of #85818 - LeSeulArtichaut:85794-diag-drop-ice, r=petrochenkovGuillaume Gomez-0/+34
Don't drop `PResult` without handling the error Fixes #85794.
2021-05-30Rollup merge of #85770 - Bobo1239:set_locale_for_sort, r=jyn514Guillaume Gomez-22/+0
Remove `--print unversioned-files` from rustdoc This flag isn't needed anymore. See #83784.
2021-05-30Rollup merge of #85709 - Aaron1011:fix-pat-crate-edition, r=petrochenkovGuillaume Gomez-0/+32
Use correct edition when parsing `:pat` matchers As described in issue #85708, we currently do not properly decode `SyntaxContext::root()` and `ExpnId::root()` from foreign crates. As a result, when we decode a span from a foreign crate with `SyntaxContext::root()`, we end up up considering it to have the edition of the *current* crate, instead of the foreign crate where it was originally created. A full fix for this issue will be a fairly significant undertaking. Fortunately, it's possible to implement a partial fix, which gives us the correct edition-dependent behavior for `:pat` matchers when the macro is loaded from another crate. Since we have the edition of the macro's defining crate available, we can 'recover' from seeing a `SyntaxContext::root()` and use the edition of the macro's defining crate. Any solution to issue #85708 must reproduce the behavior of this targeted fix - properly preserving a foreign `SyntaxContext::root()` means (among other things) preserving its edition, which by definition is the edition of the foreign crate itself. Therefore, this fix moves us closer to the correct overall solution, and does not expose any new incorrect behavior to macros.
2021-05-30Bless tests.Camille GILLOT-16/+16
2021-05-30Auto merge of #85362 - jsgf:fix-emit-metadata, r=estebankbors-0/+34
Use command line metadata path if provided If the command-line has `--emit metadata=some/path/libfoo.rmeta` then use that. Closes #85356 I couldn't find any existing tests for the `--emit TYPE=PATH` command line syntax, so I wasn't sure how to test this aside from ad-hoc manual testing. Is there a ui test type for "generated output file with expected name"?
2021-05-30Emit a hard error when a panic occurs during const-evalAaron Hill-128/+56
Previous, a panic during const evaluation would go through the `const_err` lint. This PR ensures that such a panic always causes compilation to fail.
2021-05-30Fix span of redundant generic arguments0yoyoyo-93/+237
2021-05-30Update mir opt testsbjorn3-24/+24
2021-05-30Update testsbjorn3-68/+68
2021-05-30Auto merge of #83772 - jhpratt:revamp-step-trait, r=Mark-Simulacrumbors-11/+17
Make `Step` trait safe to implement This PR makes a few modifications to the `Step` trait that I believe better position it for stabilization in the short term. In particular, 1. `unsafe trait TrustedStep` is introduced, indicating that the implementation of `Step` for a given type upholds all stated invariants (which have remained unchanged). This is gated behind a new `trusted_step` feature, as stabilization is realistically blocked on min_specialization. 2. The `Step` trait is internally specialized on the `TrustedStep` trait, which avoids a serious performance regression. 3. `TrustedLen` is implemented for `T: TrustedStep` as the latter's invariants subsume the former's. 4. The `Step` trait is no longer `unsafe`, as the invariants must not be relied upon by unsafe code (unless the type implements `TrustedStep`). 5. `TrustedStep` is implemented for all types that implement `Step` in the standard library and compiler. 6. The `step_trait_ext` feature is merged into the `step_trait` feature. I was unable to find any reasoning for the features being split; the `_unchecked` methods need not necessarily be stabilized at the same time, but I think it is useful to have them under the same feature flag. All existing implementations of `Step` will be broken, as it is not possible to `unsafe impl` a safe trait. Given this trait only exists on nightly, I feel this breakage is acceptable. The blanket `impl<T: Step> TrustedLen for T` will likely cause some minor breakage, but this should be covered by the equivalent impl for `TrustedStep`. Hopefully these changes are sufficient to place `Step` in decent position for stabilization, which would allow user-defined types to be used with `a..b` syntax.
2021-05-30Don't drop `PResult` without handling the errorLeSeulArtichaut-0/+34
2021-05-29Auto merge of #85698 - ehuss:incremental-session-panic, r=estebankbors-0/+15
Don't panic when failing to initialize incremental directory. This removes a panic when rustc fails to initialize the incremental directory. This can commonly happen on various filesystems that don't support locking (often various network filesystems). Panics can be confusing and scary, and there are already plenty of issues reporting this. This has been panicking since 1.22 due to I think #44502 which was a major rework of how things work. Previously, things were simpler and the [`load_dep_graph`](https://github.com/rust-lang/rust/blob/1.21.0/src/librustc_incremental/persist/load.rs#L43-L65) function would emit an error and then continue on without panicking. With 1.22, [`load_dep_graph`](https://github.com/rust-lang/rust/blob/1.22.0/src/librustc_incremental/persist/load.rs#L44) was changed so that it assumes it can load the data without errors. Today, the problem is that it calls [`prepare_session_directory`](https://github.com/rust-lang/rust/blob/fbf1b1a7193cda17008ab590e06ad28d9924023b/compiler/rustc_interface/src/passes.rs#L175-L179) and then immediately calls `garbage_collect_session_directories` which will panic since the session is `IncrCompSession::NotInitialized`. The solution here is to have `prepare_session_directory` return an error that must be handled so that compilation stops if it fails. Some other options: * Ignore directory lock failures. * Print a warning on directory lock failure, but otherwise continue with incremental enabled. * Print a warning on directory lock failure, and disable incremental. * Provide a different locking mechanism. Cargo ignores lock errors if locking is not supported, so that would be a precedent for the first option. These options would require quite a bit more changes, but I'm happy to entertain any of them, as I think they all have valid justifications. There is more discussion on the many issues where this is reported: #49773, #59224, #66513, #76251. I'm not sure if this can be considered closing any of those, though, since I think there is some value in discussing if there is a way to avoid the error altogether. But I think it would make sense to at least close all but one to consolidate them.
2021-05-29Use correct edition when parsing `:pat` matchersAaron Hill-0/+32
As described in issue #85708, we currently do not properly decode `SyntaxContext::root()` and `ExpnId::root()` from foreign crates. As a result, when we decode a span from a foreign crate with `SyntaxContext::root()`, we end up up considering it to have the edition of the *current* crate, instead of the foreign crate where it was originally created. A full fix for this issue will be a fairly significant undertaking. Fortunately, it's possible to implement a partial fix, which gives us the correct edition-dependent behavior for `:pat` matchers when the macro is loaded from another crate. Since we have the edition of the macro's defining crate available, we can 'recover' from seeing a `SyntaxContext::root()` and use the edition of the macro's defining crate. Any solution to issue #85708 must reproduce the behavior of this targeted fix - properly preserving a foreign `SyntaxContext::root()` means (among other things) preserving its edition, which by definition is the edition of the foreign crate itself. Therefore, this fix moves us closer to the correct overall solution, and does not expose any new incorrect behavior to macros.
2021-05-29Auto merge of #85540 - GuillaumeGomez:better-result-dom-generation, r=jshabors-0/+15
Better result dom generation First commit is from https://github.com/rust-lang/rust/pull/85506. We realized in https://github.com/rust-lang/rust/pull/85506#issuecomment-844984162 thanks to `@dns2utf8` that in some cases, the generated search result DOM was invalid. This was not strict enough and the DOM was inserted as a big string, which wasn't great. r? `@jsha`
2021-05-29Fix incremental-session-fail to work when run as root.Eric Huss-2/+1
2021-05-29Auto merge of #85767 - lqd:stackless_span_stacks, r=oli-obkbors-14/+15
A bit more polish on const eval errors This PR adds a bit more polish to the const eval errors: - a slight improvement to the PME messages from #85633: I mentioned there that the erroneous item's paths were dependent on the environment, and could be displayed fully qualified or not. This can obscure the items when they come from a dependency. This PR uses the pretty-printing code ensuring the items' paths are not trimmed. - whenever there are generics involved in an item where const evaluation errors out, the error message now displays the instance and its const arguments, so that we can see which instantiated item and compile-time values lead to the error. So we get this slight improvement for our beloved `stdarch` example, on nightly: ``` error[E0080]: evaluation of constant value failed --> ./stdarch/crates/core_arch/src/macros.rs:8:9 | 8 | assert!(IMM >= MIN && IMM <= MAX, "IMM value not in expected range"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'IMM value not in expected range', /rustc/9111b8ae9793f18179a1336417618fc07a9cac85/library/core/src/../../stdarch/crates/core_arch/src/macros.rs:8:9 | ``` to this PR's: ``` error[E0080]: evaluation of `core::core_arch::macros::ValidateConstImm::<51_i32, 0_i32, 15_i32>::VALID` failed --> ./stdarch/crates/core_arch/src/macros.rs:8:9 | 8 | assert!(IMM >= MIN && IMM <= MAX, "IMM value not in expected range"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'IMM value not in expected range', ./stdarch/crates/core_arch/src/macros.rs:8:9 | ``` with this PR. Of course this is an idea from Oli, so maybe r? `@oli-obk` if they have the time.
2021-05-28Add test for --emit TYPE=pathJeremy Fitzhardinge-0/+34
2021-05-28Auto merge of #85607 - LeSeulArtichaut:thir-unsafeck-closures, r=nikomatsakisbors-14/+142
Make closures inherit their parent's "safety context" Fixes rust-lang/project-thir-unsafeck#9, ~~blocked on #85273~~. r? `@nikomatsakis`
2021-05-28Remove `--print unversioned-files` from rustdocBoris-Chengbiao Zhou-22/+0
This flag isn't needed anymore. See #83784.
2021-05-29Diagnose use sanitizers with crt-static12101111-0/+9
2021-05-28Auto merge of #85700 - Bobo1239:dso_local_ppc64, r=nagisabors-2/+9
Fix static relocation model for PowerPC64 We now also use `should_assume_dso_local()` for declarations and port two additional cases from clang: - Exclude PPC64 [1] - Exclude thread-local variables [2] [1]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1038-L1040 [2]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1048-L1050 Tbh I don't know enough about PowerPC(64) to explain why the TOC (table of contents; like the GOT in x86?) is still needed even with the static relocation model. But with these changes [Rust-For-Linux](https://github.com/Rust-for-Linux/linux) runs again on ppc64le. (instead of [getting loaded successfully but crashing](https://github.com/Bobo1239/linux/runs/2646478783?check_suite_focus=true#step:47:358)) r? `@nagisa`
2021-05-28Auto merge of #84968 - FabianWolff:master, r=estebankbors-7/+22
Fix incorrect suggestions for E0605 Fixes #84598. Here is a simplified version of the problem presented in issue #84598: ```Rust #![allow(unused_variables)] #![allow(dead_code)] trait T { fn t(&self) -> i32; } unsafe fn foo(t: *mut dyn T) { (t as &dyn T).t(); } fn main() {} ``` The current output is: ``` error[E0605]: non-primitive cast: `*mut (dyn T + 'static)` as `&dyn T` --> src/main.rs:7:5 | 7 | (t as &dyn T).t(); | ^^^^^^^^^^^^^ invalid cast | help: borrow the value for the cast to be valid | 7 | (&t as &dyn T).t(); | ^ ``` This is incorrect, though: The cast will _not_ be valid when writing `&t` instead of `t`: ``` error[E0277]: the trait bound `*mut (dyn T + 'static): T` is not satisfied --> t4.rs:7:6 | 7 | (&t as &dyn T).t(); | ^^ the trait `T` is not implemented for `*mut (dyn T + 'static)` | = note: required for the cast to the object type `dyn T` ``` The correct suggestion is `&*t`, which I have implemented in this pull request. Of course, this suggestion will always require an unsafe block, but arguably, that's what the user really wants if they're trying to cast a pointer to a reference. In any case, claiming that the cast will be valid after implementing the suggestion is overly optimistic, as the coercion logic doesn't seem to resolve all nested obligations, i.e. the cast may still be invalid after implementing the suggestion. I have therefore rephrased the suggestion slightly ("consider borrowing the value" instead of "borrow the value for the cast to be valid"). Additionally, I have fixed another incorrect suggestion not mentioned in #84598, which relates to casting immutable references to mutable ones: ```rust fn main() { let mut x = 0; let m = &x as &mut i32; } ``` currently leads to ``` error[E0605]: non-primitive cast: `&i32` as `&mut i32` --> t5.rs:3:13 | 3 | let m = &x as &mut i32; | ^^^^^^^^^^^^^^ invalid cast | help: borrow the value for the cast to be valid | 3 | let m = &mut &x as &mut i32; | ^^^^ ``` which is obviously incorrect: ``` error[E0596]: cannot borrow data in a `&` reference as mutable --> t5.rs:3:13 | 3 | let m = &mut &x as &mut i32; | ^^^^^^^ cannot borrow as mutable ``` I've changed the suggestion to a note explaining the problem: ``` error[E0605]: non-primitive cast: `&i32` as `&mut i32` --> t5.rs:3:13 | 3 | let m = &x as &mut i32; | ^^^^^^^^^^^^^^ invalid cast | note: this reference is immutable --> t5.rs:3:13 | 3 | let m = &x as &mut i32; | ^^ note: trying to cast to a mutable reference type --> t5.rs:3:19 | 3 | let m = &x as &mut i32; | ^^^^^^^^ ``` In this example, it would have been even nicer to suggest replacing `&x` with `&mut x`, but this would be much more complex because we would have to take apart the expression to be cast (currently, we only look at its type), and `&x` could be stored in a variable, where such a suggestion would not even be directly applicable: ```rust fn main() { let mut x = 0; let r = &x; let m = r as &mut i32; } ``` My solution covers this case, too.
2021-05-28Fix static relocation model for PowerPC64Boris-Chengbiao Zhou-2/+9
We now also use `should_assume_dso_local()` for declarations and port two additional cases from clang: - Exclude PPC64 [1] - Exclude thread-local variables [2] [1]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1038-L1040 [2]: https://github.com/llvm/llvm-project/blob/033138ea452f5f493fb5095e5963419905ad12e1/clang/lib/CodeGen/CodeGenModule.cpp#L1048-L1050
2021-05-28const eval errors: display the current item instance if there are generics ↵Rémy Rakic-12/+13
involved
2021-05-27don't trim paths in collector PME messageRémy Rakic-2/+2
2021-05-27Test THIR unsafeck for unsafe ops in closuresLeSeulArtichaut-14/+142
2021-05-27Rollup merge of #85722 - GuillaumeGomez:trait-toggle, r=jshaGuillaume Gomez-1/+5
Fix trait methods' toggle A `<details>` tag wasn't closed on trait methods, which created broken DOM. I also used this occasion to only generate the toggle in case there is documentation on the method. r? `@jsha`
2021-05-27Auto merge of #85732 - Smittyvb:trait-alias-camelcase-lint, r=varkorbors-0/+18
Lint against non-CamelCase trait alias names Type aliases are linted as such, so (unstable) trait aliases should be treated the same way.
2021-05-26Add test to check behavior when incremental session init fails.Eric Huss-0/+16
2021-05-27Rollup merge of #85564 - ↵Dylan DPC-0/+27
pnkfelix:issue-85435-readd-capture-disjoint-fields-gate, r=nikomatsakis readd capture disjoint fields gate This readds a feature gate guard that was added in PR #83521. (Basically, there were unintended consequences to the code exposed by removing the feature gate guard.) The root bug still remains to be resolved, as discussed in issue #85561. This is just a band-aid suitable for a beta backport. Cc issue #85435 Note that the latter issue is unfixed until we backport this (or another fix) to 1.53 beta
2021-05-27Rollup merge of #84701 - nikomatsakis:stabilize-member-constraints-61997, ↵Dylan DPC-140/+29
r=jackh726 stabilize member constraints Stabilizes the use of "member constraints" in solving `impl Trait` bindings. This is a step towards stabilizing a "MVP" of "named impl Trait". # Member constraint stabilization report | Info | | | --- | --- | | Tracking issue | [rust-lang/rust#61997](https://github.com/rust-lang/rust/issues/61997) | | Implementation history | [rust-lang/rust#61775] | | rustc-dev-guide coverage | [link](https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference/member_constraints.html) | | Complications | [rust-lang/rust#61773] | [rust-lang/rust#61775]: https://github.com/rust-lang/rust/pull/61775 [rust-lang/rust#61773]: https://github.com/rust-lang/rust/issues/61773 ## Background Member constraints are an extension to our region solver that was introduced to make async fn region solving tractable. There are used in situations like the following: ```rust fn foo<'a, 'b>(...) -> impl Trait<'a, 'b> { .. } ``` The problem here is that every region R in the hidden type must be equal to *either* `'a` *or* `'b` (or `'static`). This cannot be expressed simply via 'outlives constriants' like `R: 'a`. Therefore, we introduce a 'member constraint' `R member of ['a, 'b]`. These constraints were introduced in [rust-lang/rust#61775]. At the time, we kept them feature gated and used them only for `impl Trait` return types that are derived from `async fn`. The intention, however, was always to support them in other contexts once we had time to gain more experience with them. **In the time since their introduction, we have encountered no surprises or bugs due to these member constraints.** They are tested extensively as part of every async function that involves multiple unrelated lifetimes in its arguments. ## Tests The behavior of member constraints is covered by the following tests: * [`src/test/ui/async-await/multiple-lifetimes`](https://github.com/rust-lang/rust/tree/20e032e65007ff1376e8480c1fbdb0a5068028fa/src/test/ui/async-await/multiple-lifetimes) -- tests using the async await, which are mostly already stabilized * [`src/test/ui/impl-trait/multiple-lifetimes.rs`](https://github.com/rust-lang/rust/blob/20e032e65007ff1376e8480c1fbdb0a5068028fa/src/test/ui/impl-trait/multiple-lifetimes.rs) * [`src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-unsuited.rs`](https://github.com/rust-lang/rust/blob/20e032e65007ff1376e8480c1fbdb0a5068028fa/src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-unsuited.rs) * [`src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-fg.rs`](https://github.com/rust-lang/rust/blob/20e032e65007ff1376e8480c1fbdb0a5068028fa/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-fg.rs) * [`src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.rs`](https://github.com/rust-lang/rust/blob/20e032e65007ff1376e8480c1fbdb0a5068028fa/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.rs) These tests cover a number of scenarios: * `-> implTrait<'a, 'b>` with unrelated lifetimes `'a` and `'b`, as described above * `async fn` that returns an `impl Trait` like the previous case, which desugars to a kind of "nested" impl trait like `impl Future<Output = impl Trait<'a, 'b>>` ## Potential concerns There is a potential interaction with `impl Trait` on local variables, described in [rust-lang/rust#61773]. The challenge is that if you have a program like: ```rust= trait Foo<'_> { } impl Foo<'_> for &u32 { } fn bar() { let x: impl Foo<'_> = &44; // let's call the region variable for `'_` `'1` } ``` then we would wind up with `'0 member of ['1, 'static]`, where `'0` is the region variable in the hidden type (`&'0 u32`) and `'1` is the region variable in the bounds `Foo<'1>`. This is tricky because both `'0` and `'1` are being inferred -- so making them equal may have other repercussions. That said, `impl Trait` in bindings are not stable, and the implementation is pretty far from stabilization. Moreover, the difficulty highlighted here is not due to the presence of member constraints -- it's inherent to the design of the language. In other words, stabilizing member constraints does not actually cause us to accept anything that would make this problem any harder. So I don't see this as a blocker to stabilization of member constraints; it is potentially a blocker to stablization of `impl trait` in let bindings.
2021-05-27Rollup merge of #84221 - ABouttefeux:generic-arg-elision, r=estebankDylan DPC-8/+214
E0599 suggestions and elision of generic argument if no canditate is found fixes #81576 changes: In error E0599 (method not found) generic argument are eluded if the method was not found anywhere. If the method was found in another inherent implementation suggest that it was found elsewhere. Example ```rust struct Wrapper<T>(T); struct Wrapper2<T> { x: T, } impl Wrapper2<i8> { fn method(&self) {} } fn main() { let wrapper = Wrapper(i32); wrapper.method(); let wrapper2 = Wrapper2{x: i32}; wrapper2.method(); } ``` ``` Error[E0599]: no method named `method` found for struct `Wrapper<_>` in the current scope .... error[E0599]: no method named `method` found for struct `Wrapper2<i32>` in the current scope ... = note: The method was found for Wrapper2<i8>. ``` I am not very happy with the ```no method named `test` found for struct `Vec<_, _>` in the current scope```. I think it might be better to show only one generic argument `Vec<_>` if there is a default one. But I haven't yet found a way to do that,
2021-05-26Lint against non-camelCase trait alias namesSmitty-0/+18
Type aliases are linted as such, so (unstable) trait aliases should be treated the same way.