Implement destructuring assignment for tuples
This is the first step towards implementing destructuring assignment (RFC: https://github.com/rust-lang/rfcs/pull/2909, tracking issue: #71126). This PR is the first part of #71156, which was split up to allow for easier review.
Quick summary: This change allows destructuring the LHS of an assignment if it's a (possibly nested) tuple.
It is implemented via a desugaring (AST -> HIR lowering) as follows:
```rust
(a,b) = (1,2)
```
... becomes ...
```rust
{
let (lhs0,lhs1) = (1,2);
a = lhs0;
b = lhs1;
}
```
Thanks to `@varkor` who helped with the implementation, particularly around default binding modes.
r? `@petrochenkov`
inliner: Use substs_for_mir_body
Changes from 68965 extended the kind of instances that are being
inlined. For some of those, the `instance_mir` returns a MIR body that
is already expressed in terms of the types found in substitution array,
and doesn't need further substitution.
Use `substs_for_mir_body` to take that into account.
Resolves#78529.
Resolves#78560.
Additionally introduce storage markers for all temporaries created by
the inliner. The temporary introduced for destination rebrorrow, didn't
use them previously.
When examining candidates for inlining, reject those that are determined
to be recursive either because of self-recursive calls or calls to any
instances already inlined.
rustc_ast: Visit tokens stored in AST nodes in mutable visitor
After #77271 token visiting is enabled only for one visitor in `rustc_expand\src\mbe\transcribe.rs` which applies hygiene marks to tokens produced by declarative macros (`macro_rules` or `macro`), so this change doesn't affect anything else.
When a macro has some interpolated token from an outer macro in its output
```rust
macro inner() {
$interpolated
}
```
we can use the usual interpretation of interpolated tokens in token-based model - a None-delimited group - to write this macro in an equivalent form
```rust
macro inner() {
⟪ a b c d ⟫
}
```
When we are expanding the macro `inner` we need to apply hygiene marks to all tokens produced by it, including the tokens inside the group.
Before this PR we did this by visiting the AST piece inside the interpolated token and applying marks to all spans in it.
I'm not sure this is 100% correct (ideally we should apply the marks to tokens and then re-parse the AST from tokens), but it's a very good approximation at least.
We didn't however apply the marks to actual tokens stored in the nonterminal, so if we used the nonterminal as a token rather than as an AST piece (e.g. passed it to a proc macro), then we got hygiene bugs.
This PR applies the marks to tokens in addition to the AST pieces thus fixing the issue.
r? `@Aaron1011`
Rollup of 19 pull requests
Successful merges:
- #76097 (Stabilize hint::spin_loop)
- #76227 (Stabilize `Poll::is_ready` and `is_pending` as const)
- #78065 (make concurrency helper more pleasant to read)
- #78570 (Remove FIXME comment in print_type_sizes ui test suite)
- #78572 (Use SOCK_CLOEXEC and accept4() on more platforms.)
- #78658 (Add a tool to run `x.py` from any subdirectory)
- #78706 (Fix run-make tests running when LLVM is disabled)
- #78728 (Constantify `UnsafeCell::into_inner` and related)
- #78775 (Bump Rustfmt and RLS)
- #78788 (Correct unsigned equivalent of isize to be usize)
- #78811 (Make some std::io functions `const`)
- #78828 (use single char patterns for split() (clippy::single_char_pattern))
- #78841 (Small cleanup in `TypeFoldable` derive macro)
- #78842 (Honor the rustfmt setting in config.toml)
- #78843 (Less verbose debug logging from inlining integrator)
- #78852 (Convert a bunch of intra-doc links)
- #78860 (rustc_resolve: Use `#![feature(format_args_capture)]`)
- #78861 (typo and formatting)
- #78865 (Don't fire `CONST_ITEM_MUTATION` lint when borrowing a deref)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Don't fire `CONST_ITEM_MUTATION` lint when borrowing a deref
Fixes#78819
This extends the check for dereferences added in PR #77324
to cover mutable borrows, as well as direct writes. If we're operating
on a dereference of a `const` item, we shouldn't be firing the lint.
Remove FIXME comment in print_type_sizes ui test suite
## Overview
Helps with #62277
> The type sizes are likely only printed when the actual layout is computed. For generic types, this only happens during codegen.
ref: https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/Codegen.20process.20question/near/215836807
Some tests like `multiple_types.rs` are passed even if using `check-pass`. But tests should be agnostic to when the actual layout is computed. The `build-pass` is intentionally used for them. I remove FIXME comments.
revert #75443, update mir validator
This PR reverts rust-lang#75443 to fix rust-lang#75992 and instead uses rust-lang#75419 to fix rust-lang#75313.
Adapts rust-lang#75419 to correctly deal with unevaluated constants as otherwise some `feature(const_evaluatable_checked)` tests would ICE.
Note that rust-lang#72793 was also fixed by rust-lang#75443, but as that issue only concerns `feature(type_alias_impl_trait)` I deleted that test case for now and would reopen that issue.
rust-lang#75443 may have also allowed some other code to now successfully compile which would make this revert a breaking change after 2 stable versions, but I hope that this is a purely theoretical concern.
See https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/generator.20upvars/near/214617274 for more reasoning about this.
r? `@nikomatsakis` `@eddyb` `@RalfJung`
This PR allows using `#[repr(simd)]` on ADTs containing a
single array field:
```rust
#[repr(simd)] struct S0([f32; 4]);
#[repr(simd)] struct S1<const N: usize>([f32; N]);
#[repr(simd)] struct S2<T, const N: usize>([T; N]);
```
This should allow experimenting with portable packed SIMD
abstractions on nightly that make use of const generics.
Fixes#78819
This extends the check for dereferences added in PR #77324
to cover mutable borrows, as well as direct writes. If we're operating
on a dereference of a `const` item, we shouldn't be firing the lint.
Revert "Revert "resolve: Avoid "self-confirming" import resolutions in one more case""
Specifically, this reverts commit b20bce8ce5 from #77421 to fix#77586.
The lang team has decided that for the time being we want to avoid the breakage here (perhaps for a future edition; though almost certainly not the upcoming one), though a future PR may want to add a lint around this case (and perhaps others) which are unlikely to be readable code.
r? `@petrochenkov` to confirm this is the right way to fix#77586.
Fix unreachable sub-branch detection in or-patterns
The previous implementation was too eager to avoid unnecessary "unreachable pattern" warnings. I feel more confident about this implementation than I felt about the previous one.
Fixes https://github.com/rust-lang/rust/issues/76836.
``@rustbot`` modify labels: +A-exhaustiveness-checking
Working expression optimization, and some improvements to branch-level source coverage
This replaces PR #78040 after reorganizing the original commits (by request) into a more logical sequence of major changes.
Most of the work is in the MIR `transform/coverage/` directory (originally, `transform/instrument_coverage.rs`).
Note this PR includes some significant additional debugging capabilities, to help myself and any future developer working on coverage improvements or issues.
In particular, there's a new Graphviz (.dot file) output for the coverage graph (the `BasicCoverageBlock` control flow graph) that provides ways to get some very good insight into the relationships between the MIR, the coverage graph BCBs, coverage spans, and counters. (There are also some cool debugging options, available via environment variable, to alter how some data in the graph appears.)
And the code for this Graphviz view is actually generic... it can be used by any implementation of the Rust `Graph` traits.
Finally (for now), I also now output information from `llvm-cov` that shows the actual counters and spans it found in the coverage map, and their counts (from the `--debug` flag). I found this to be enormously helpful in debugging some coverage issues, so I kept it in the test results as well for additional context.
`@tmandry` `@wesleywiser`
r? `@tmandry`
Here's an example of the new coverage graph:
* Within each `BasicCoverageBlock` (BCB), you can see each `CoverageSpan` and its contributing statements (MIR `Statement`s and/or `Terminator`s)
* Each `CoverageSpan` has a `Counter` or and `Expression`, and `Expression`s show their Add/Subtract operation with nested operations. (This can be changed to show the Counter and Expression IDs instead, or in addition to, the BCB.)
* The terminators of all MIR `BasicBlock`s in the BCB, including one final `Terminator`
* If an "edge counter" is required (because we need to count an edge between blocks, in some cases) the edge's Counter or Expression is shown next to its label. (Not shown in the example below.) (FYI, Edge Counters are converted into a new MIR `BasicBlock` with `Goto`)
<img width="1116" alt="Screen Shot 2020-10-17 at 12 23 29 AM" src="https://user-images.githubusercontent.com/3827298/96331095-616cb480-100f-11eb-8212-60f2d433e2d8.png">
r? `@tmandry`
FYI: `@wesleywiser`
And even though CI should now pass for MacOS, the llvm-cov show --debug
flag does not work when developing outside of CI, so I'm disabling it
for MacOS by default.
And restored missing error message from llvm-cov show
And since some CI builds disable LLVM assertions (which disables the
--debug option in llvm-cov show), I check to see if LLVM assertions are
disabled, and if so, I don't add --debug and don't check the counter
file diffs.
More portable way to make python 2/3 portable.
Strip Args line (with hardcoded paths) from debug counters output.
Ignore diff failures from llvm-cov debug output files ("counters"
files), since generic function instantiations will appear in those files
with mangled names. (Sadly, the demangler is apparently not applied to
the debug output.)
Implementing the Graph traits for the BasicCoverageBlock
graph.
optimized replacement of counters with expressions plus new BCB graphviz
* Avoid adding coverage to unreachable blocks.
* Special case for Goto at the end of the body. Make it non-reportable.
Improved debugging and formatting options (from env)
Don't automatically add counters to BCBs without CoverageSpans. They may
still get counters but only if there are dependencies from
other BCBs that have spans, I think.
Make CodeRegions optional for Counters too. It is
possible to inject counters (`llvm.instrprof.increment` intrinsic calls
without corresponding code regions in the coverage map. An expression
can still uses these counter values.
Refactored instrument_coverage.rs -> instrument_coverage/mod.rs, and
then broke up the mod into multiple files.
Compiling with coverage, with the expression optimization, works on
the json5format crate and its dependencies.
Refactored debug features from mod.rs to debug.rs
Changes from 68965 extended the kind of instances that are being
inlined. For some of those, the `instance_mir` returns a MIR body that
is already expressed in terms of the types found in substitution array,
and doesn't need further substitution.
Use `substs_for_mir_body` to take that into account.
reverse binding order in matches to allow the subbinding of copyable fields in bindings after @
Fixes#69971
### TODO
- [x] Regression tests
r? `@oli-obk`
(rustdoc) fix test for trait impl display
The test checks that parameters and return values with `impl Trait` types are correctly generated in rustdoc's output.
In essence, the previous version of the test checked the absence of values that would never be generated by rustdoc, so it could basically never fail. These values were adjusted to the expected output and are now required to exist in rustdoc's output. See https://github.com/rust-lang/rust/issues/55201#issuecomment-716182474 for a detailed explanation of the reasoning behind the changes.
Note that the output of rustdoc for `impl Trait`s in parameters and return values did not change since the inital test creation, so this PR only modifies the test.
Closes#55201
