Add regression test for #70155.
With #70166 merged, `RangeInclusive` now derives `PartialEq` and `Eq`, implementing structural equality and as a side effect the range is now usable with const generics, closing #70155.
As per [#70166 (comment)](https://github.com/rust-lang/rust/pull/70166#issuecomment-601872201) a test is added to avoid a change to the private fields or the equality implementation of the range from subtly reverting #70155.
Fix invalid suggestion on `&mut` iterators yielding `&` references
Fixes#69789.
rustc suggested an invalid code when `&` reference from `&mut` iterator is mutated. The compiler knew we're mutating a value behind `&` reference, but as the assignment RHS is from desugaring, it could only see the iterator expression from source and inserted `mut` there.
r? @estebank
Improve E0308 error message wording
Hi folks,
I made [a post on Reddit](https://old.reddit.com/r/rust/comments/fmi11x/consider_linting_rusts_documentationerror_text/) about how (IMO) the docs/error messages can be a bit intimidating, one thing led to another, and I was encouraged to submit a Pull Request if I felt I could re-phrase the error message that I used as an example.
So that's this Pull Request. Open to any feedback or style changes, and I understand this is subjective.
(On another note: I am happy to see [this message was recently improved](https://github.com/rust-lang/rust/pull/69139) in `master`, so it's already better than it is in stable Rust 1.42.0.)
Ideally the last sentence could be split into at least two: [sentence explaining the inferred type.] [Sentence explaining explicit type.] [Sentence that summarizes that "this is bad," and why.]
But I'm not sure how to do so; I'm wary of writing something that turns out to be technically incorrect.
Remove const eval loop detector
Now that there is a configurable instruction limit for CTFE (see #67260), we can replace the loop detector with something much simpler. See #66946 for more discussion about this. Although the instruction limit is nightly-only, the only practical way to reach the default limit uses nightly-only features as well (although CTFE will still execute code using such features inside an array initializer on stable).
This will at the very least require a crater run, since it will result in an error wherever the "long running const eval" warning appeared before. We may need to increase the default for `const_eval_limit` to work around this.
Resolves#54384 cc #49980
r? @oli-obk cc @RalfJung
In addition to the regression test of `RangeInclusive` for #70155, now all range types are checked for usability within const generics:
- `RangeFrom`
- `RangeFull`
- `RangeToInclusive`
- `RangeTo`
- `Range`
The test are moved from `test\ui\const-generics\issues\issue-70155` to `test\ui\const-generics\std\range` in anticipation of future similar tests for std types.
Tweak output for invalid negative impl errors
Follow up to #69722. Tweak negative impl errors emitted in the HIR:
```
error[E0192]: invalid negative impl
--> $DIR/E0192.rs:9:6
|
LL | impl !Trait for Foo { }
| ^^^^^^
|
= note: negative impls are only allowed for auto traits, like `Send` and `Sync`
```
rustc: keep upvars tupled in {Closure,Generator}Substs.
Previously, each closure/generator capture's (aka "upvar") type was tracked as one "synthetic" type parameter in the closure/generator substs, and figuring out where the parent `fn`'s generics end and the synthetics start involved slicing at `tcx.generics_of(def_id).parent_count`.
Needing to query `generics_of` limited @davidtwco (who wants to compute some `TypeFlags` differently for parent generics vs upvars, and `TyCtxt` is not available there), which is how I got started on this, but it's also possible that the `generics_of` queries are slowing down `{Closure,Generator}Substs` methods.
To give an example, for a `foo::<T, U>::{closure#0}` with captures `x: X` and `y: Y`, substs are:
* before this PR: `[T, U, /*kind*/, /*signature*/, X, Y]`
* after this PR: `[T, U, /*kind*/, /*signature*/, (X, Y)]`
You can see that, with this PR, no matter how many captures, the last 3 entries in the substs (or 5 for a generator) are always the "synthetic" ones, with the last one being the tuple of capture types.
r? @nikomatsakis cc @Zoxc
Increase verbosity when suggesting subtle code changes
Do not suggest changes that are actually quite small inline, to minimize the likelihood of confusion.
Fix#69243.
Previously, we threw away the `Span` associated with a definition's
identifier when we encoded crate metadata, causing us to lose location
and hygiene information.
We now store the identifier's `Span` in the crate metadata.
When we decode items from the metadata, we combine
the name and span back into an `Ident`.
This improves the output of several tests, which previously had messages
suppressed due to dummy spans.
This is a prerequisite for #68686, since throwing away a `Span` means
that we lose hygiene information.
resolve: Avoid "self-confirming" import resolutions in one more case
So the idea behind "blacklisted bindings" is that we must ignore some name definitions during resolution because otherwise they cause infinite cycles.
E.g. import
```rust
use my_crate;
```
would refer to itself (on 2018 edition) without this blacklisting, because `use my_crate;` is the first name in scope when we are resolving `my_crate` here.
In this PR we are doing this blacklisting for the case
```rust
use same::same;
```
, namely blacklisting the second `same` when resolving the first `same`.
This was previously forgotten.
Fixes https://github.com/rust-lang/rust/issues/62767
With #70166 merged, `RangeInclusive` now derives `PartialEq` and `Eq`, implementing structural equality and as a side effect the range is now usable with const generics, closing #70155.
A test is added to avoid a change to the private fields or the equality implementation of the range from subtly reverting #70155.
parser: recover on `for<'a> |...| body` closures
When encountering `for` and `<` is 1 token ahead, interpret this as an explicitly quantified generic closure and recover, rather than attempting to parse a `for` loop. This provides both improved diagnostics as well as an insurance policy for the ability to use this as the syntax for generic closures in the future.
As requested by r? @eddyb
