Gradually expanding libstd's keyword documentation
I'm working on adding new keywords to the documentation and refreshing the incomplete older ones, and I'm hoping that I can eventually add all the standalone-usable keywords after a bunch of incremental work. It would be cool to see the keywords section of std's docs be a definitive reference as to what each keyword means when you see it, and that's what I'm aiming towards with this work.
I'm far from a Rust expert so there will inevitably be things to fix in this, also I'm not sure if this should be a bunch of quickly-merged PRs or one gradually-updated PR that gets merged once it's done.
introduce type-op for user-type ascription in NLL
Handle user-type ascription in a type operator, which gives us a lot more flexibility around the order in which we resolve things.
r? @pnkfelix
Fixes#55219Fixes#55241
It was confusingly named (`is_zero` would have been better), and it didn't even
reliably test for "is this value 0 at run-time" because out-of-bounds pointers
*can* be 0.
Add `extern crate` items to extern prelude
With this patch each `extern crate orig_name as name` item adds name `name` into the extern prelude, as if it was passed with `--extern`.
What changes this causes in practice?
Almost none! After all, `--extern` passed from Cargo was supposed to replace `extern crate` items in source, so if some code has `extern crate` item (or had it on 2015 edition), then it most likely uses `--extern` as well...
... with exception of a few important cases.
- Crates using `proc_macro`. `proc_macro` is not passed with `--extern` right now and is therefore not in extern prelude.
Together with 2018 edition import behavior this causes problems like https://github.com/rust-lang/rust/issues/54418, e.g.
```rust
extern crate proc_macro;
use proc_macro::TokenStream;
```
doesn't work.
It starts working after this patch.
- `#[no_std]` crates using `std` conditionally, like @aturon described in https://github.com/rust-lang/rust/issues/53166#issuecomment-425219286, and still wanting to write `std` instead of `crate::std`. This PR covers that case as well.
This allows us to revert placing `std` into the extern prelude unconditionally, which was, I think, a [bad idea](https://github.com/rust-lang/rust/issues/53166#issuecomment-425117829).
- Later `extern crate` syntax can be extended to support adding an alias to some local path to extern prelude, as it may be required for resolving https://github.com/rust-lang/rust/issues/54647.
Notes:
- Only `extern crate` items from the root module added to the prelude, mostly because this behavior for items from inner modules would look very strange, rather than for technical reasons.
This means you can opt out from the prelude additions with something like
```rust
mod inner {
pub(crate) extern crate foo;
}
use inner::foo;
```
- I haven't updated logic for 2018 import canaries to work fully correctly with this. The cases where it matters are pretty exotic (the `extern crate` item must be "sufficiently macro expanded") and I'd rather spend the time on eliminating the canaries entirely.
Fallback to the release number as we can't get the
git commit sha as we're not in a git repository.
Fixes#55341
Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Add regression tests for #55219 and #55241
Also another test where a duplicate-like error appears to have been
suppressed; I'm not 100% sure why this output changes, though I could
imagine that some duplicate suppression is enabled by this PR.
enforce user annotations in closure signatures
Not *quite* ready yet but I'm opening anyway. Still have to finish running tests locally.
Fixes#54692Fixes#54124
r? @matthewjasper
This fixes `issue-28848.rs` -- it also handles another case that the
AST region checker gets wrong (`wf-self-type.rs`). I don't actually
think that this is the *right way* to be enforcing this constraint --
I think we should probably do it more generally, perhaps by editing
`predicates_of` for the impl itself. The chalk-style implied bounds
setup ought to fix this.
#45829 when a renamed import conflict with a previous import
Fix the suggestion when a renamed import conflict.
It check if the snipped contains `" as "`, and if so uses everything before for the suggestion.
Fixes#55001, #54744
Previously, SelectionContext would unconditionally cache the selection
result for an obligation. This worked fine for most users of
SelectionContext, but it caused an issue when used by Rustdoc's blanket
impl finder.
The issue occured when SelectionContext chose a ParamCandidate which
contained inference variables. Since inference variables can change
between calls to select(), it's not safe to cache the selection result -
the chosen candidate might not be applicable for future results, leading
to an ICE when we try to run confirmation.
This commit prevents SelectionContext from caching any ParamCandidate
that contains inference variables. This should always be completely
safe, as trait selection should never depend on a particular result
being cached.
I've also added some extra debug!() statements, which I found helpful in
tracking down this bug.
`compute_missing_ctors` is called a lot. It produces a vector, which can
be reasonably large (e.g. 100+ elements), but the vector is almost
always only checked for emptiness.
This commit changes `compute_missing_ctors` so it can be called in a
cheap way that just indicates if the vector would be empty. If
necessary, the function can subsequently be called in an expensive way
to compute the full vector.
This change reduces instruction counts for several benchmarks up to 2%.
