Explain non-dropped sender recv in docs
Original senders that are still hanging around could cause
Receiver::recv to not block since this is a potential footgun
for beginners, clarify more on this in the docs for readers to
be aware about it.
Maybe it would be better to show an example of the pattern where `drop(tx)` is used when it is being cloned multiple times? Although I have seen it in quite a few articles but I am surprised that this part is not very clear with the current words without careful reading.
> If the corresponding Sender has disconnected, or it disconnects while this call is blocking, this call will wake up and return Err to indicate that no more messages can ever be received on this channel. However, since channels are buffered, messages sent before the disconnect will still be properly received.
Some words there may seemed similar if I carefully read and relate it but if I am new, I probably does not know "drop" makes it "disconnected". So I mention the words "drop" and "alive" to make it more relatable to lifetime.
rustdoc: revert deref recur to resume inclusion of impl ExtTrait<Local> for ExtType
As discussed here: https://github.com/rust-lang/rust/issues/82465#issuecomment-829290384, Revert PR #80653 to resolve issue #82465.
Issue #82465 was we had stopped including certain trait implementations, namely implementations on an imported type of an imported trait *instantiated on a local type*. That bug was injected by PR #80653.
Reverting #80653 means we don't list all the methods that you have accessible via recursively applying `Deref`.
[Discussion in last week's rustc triage meeting](https://zulip-archive.rust-lang.org/238009tcompilermeetings/19557weekly2021042954818.html#236680594) led us to conclude that the bug was worse than the enhancement, and there was not an obvious fix for the bug itself. So for the short term we remove the enhancement, while in the long term we will work on figuring out a way to have our imported trait implementation cake and eat it too.
Improve CTFE UB validation error messages
As mentioned in https://github.com/rust-lang/rust/pull/86245#discussion_r650494012 this PR slightly improves the formatting of validation errors, to move the path to the error prefix.
From:
`type validation failed: encountered invalid vtable: size is bigger than largest supported object at .0`
To:
`type validation failed at .0: encountered invalid vtable: size is bigger than largest supported object`.
Fix force-warns to allow dashes.
The `--force-warns` flag was not allowing lint names with dashes, only supporting underscores. This changes it to allow dashes to match the behavior of the A/W/D/F flags.
Revert #85176 addition of `clone_from` for `ManuallyDrop`
Forwarding `clone_from` to the inner value changes the observable behavior, as previously the inner value would *not* be dropped by the default implementation.
Frankly, this is a super-niche case, so #85176 is welcome to argue the behavior should be otherwise! But if we overrride it, IMO documenting the behavior would be good.
Example: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=c5d0856686fa850c1d7ee16891014efb
Fix font weight
Fixes#86256.
I realized that the only cases where we actually needed to have bold text was inside `impl-items`.
cc `@camelid`
r? `@jsha`
Fix ICEs on invalid vtable size/alignment const UB errors
The invalid vtable size/alignment errors from `InterpCx::read_size_and_align_from_vtable` were "freeform const UB errors", causing ICEs when reaching validation. This PR turns them into const UB hard errors to catch them during validation and avoid that.
Fixes#86193
r? `@RalfJung`
(It seemed cleaner to have 2 variants but they can be merged into one variant with a message payload if you prefer that ?)
Update cargo
11 commits in aa8b09297bb3156b849e73db48af4cd050492fe6..44456677b5d1d82fe981c955dc5c67734b31f340
2021-06-09 00:28:53 +0000 to 2021-06-12 18:00:01 +0000
- Fix package_default_run test. (rust-lang/cargo#9577)
- Change how the fix_deny_warnings_but_not_others test works (rust-lang/cargo#9571)
- Add mising documentation regarding `cargo doc` (rust-lang/cargo#9565)
- Implement warning for ignored trailing arguments (rust-lang/cargo#9561)
- Make clippy happy (rust-lang/cargo#9569)
- Fix rustc/rustdoc config values to be config-relative. (rust-lang/cargo#9566)
- Update rustfix. (rust-lang/cargo#9567)
- Warn if an "all" target is specified, but we don't match anything (rust-lang/cargo#9549)
- add default_run to SerializedPackage (rust-lang/cargo#9550)
- respect user choice of lib/bin over heuristics (rust-lang/cargo#9522)
- Add a mean to mutably access the members of a workspace (rust-lang/cargo#9547)
Pretty print generator witness only in `-Zverbose` mode
In release build of deeply-nested-async benchmark the size of
`no-opt.bc` file is reduced from 46MB to 62kB.
Helps with #84873, where in one of reported test cases the size of `no-opt.bc`
file is reduced from 2.3GB to 799kB.
Implement nonzero arithmetics for NonZero types.
Hello'all, this is my first PR to this repo.
Non-zero natural numbers are stable by addition/multiplication/exponentiation, so it makes sense to make this arithmetic possible with `NonZeroU*`.
The major pitfall is that overflowing underlying `u*` types possibly lead to underlying `0` values, which break the major invariant of `NonZeroU*`. To accommodate it, only `checked_` and `saturating_` operations are implemented.
Other variants allowing wrapped results like `wrapping_` or `overflowing_` are ruled out *de facto*.
`impl Add<u*> for NonZeroU* { .. }` was considered, as it panics on overflow which enforces the invariant, but it does not so in release mode. I considered forcing `NonZeroU*::add` to panic in release mode by deferring the check to `u*::checked_add`, but this is less explicit for the user than directly using `NonZeroU*::checked_add`.
Following `@Lokathor's` advice on zulip, I have dropped the idea.
`@poliorcetics` on Discord also suggested implementing `_sub` operations, but I'd postpone this to another PR if there is a need for it. My opinion is that it could be useful in some cases, but that it makes less sense because non-null natural numbers are not stable by subtraction even in theory, while the overflowing problem is just about technical implementation.
One thing I don't like is that the type of the `other` arg differs in every implementation: `_add` methods accept any raw positive integer, `_mul` methods only accept non-zero values otherwise the invariant is also broken, and `_pow` only seems to accept `u32` for a reason I ignore but that seems consistent throughout `std`. Maybe there is a better way to harmonize this?
This is it, Iope I haven't forgotten anything and I'll be happy to read your feedback.
Do not suggest to add type annotations for unnameable types
Consider this example:
```rust
const A = || 42;
struct S<T> { t: T }
const B: _ = S { t: || 42 };
```
This currently produces the following output:
```
error: missing type for `const` item
--> src/lib.rs:1:7
|
1 | const A = || 42;
| ^ help: provide a type for the item: `A: [closure@src/lib.rs:1:11: 1:16]`
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> src/lib.rs:4:10
|
4 | const B: _ = S { t: || 42 };
| ^
| |
| not allowed in type signatures
| help: replace `_` with the correct type: `S<[closure@src/lib.rs:4:21: 4:26]>`
error: aborting due to 2 previous errors
```
However, these suggestions are obviously useless, because the suggested types cannot be written down. With my changes, the suggestion is replaced with a note, because there is no simple fix:
```
error: missing type for `const` item
--> test.rs:1:7
|
1 | const A = || 42;
| ^
|
note: however, the inferred type `[closure@test.rs:1:11: 1:16]` cannot be named
--> test.rs:1:11
|
1 | const A = || 42;
| ^^^^^
error[E0121]: the type placeholder `_` is not allowed within types on item signatures
--> test.rs:4:10
|
4 | const B: _ = S { t: || 42 };
| ^ not allowed in type signatures
|
note: however, the inferred type `S<[closure@test.rs:4:21: 4:26]>` cannot be named
--> test.rs:4:14
|
4 | const B: _ = S { t: || 42 };
| ^^^^^^^^^^^^^^
error: aborting due to 2 previous errors
```
Original senders that are still hanging around could cause
Receiver::recv to not block since this is a potential footgun
for beginners, clarify more on this in the docs for readers to
be aware about it.
Fix minor tidbits in sender recv doc
Co-authored-by: Dylan DPC <dylan.dpc@gmail.com>
Add example for unbounded receive loops in doc
Show the drop(tx) pattern, based on tokio docs
https://tokio-rs.github.io/tokio/doc/tokio/sync/index.html
Fix example code for drop sender recv
Fix wording in sender docs
Co-authored-by: Josh Triplett <josh@joshtriplett.org>
Hash DefId in rustc_span.
This is mostly just moving code around. Changes are simplifications of unneeded callbacks from rustc_span to rustc_middle.
r? `@petrochenkov`
Make `relate_type_and_mut` public
#85343 improved diagnostics around `Relate` impls but made `relate_type_and_mut` private, which was accessible as `relate` previously. This makes it public so that we can use it on rust-semverver.
r? ```@Aaron1011```
Detect incorrect vtable alignment during const eval
This PR fixes#86132 by detecting invalid alignment values for trait objects in the interpreter, and emitting an error about this conversion failure, to avoid the ICE.
I've noticed that the error emitted at a50d72158e/compiler/rustc_mir/src/interpret/traits.rs (L163-L166) doesn't seem to be present in the const-ub tests, so I've tried adding a test that triggers both of these cases: one for the invalid size, and another for the invalid alignment that #86132 tracks (I have found different magic values triggering different `Align::from_bytes` errors than the "power of 2" one, if need be).
However, when doing that, I *cannot* for the life of me figure out the correct incantation to make these 2 errors trigger with the "it is undefined behavior to use this value" message rather than the "any use of this value will cause an error" lint.
I've tried Oli's suggestions of different values, tuples and arrays, using the transparent wrapper trick from the other tests and I was only able to trigger the regular const-ub errors about the size of the vtable, or that the drop pointer was invalid. Maybe these "type validation failed" errors happen before this part of the interpreter is reached and there just needs some magic incorrect values to bypass them, I don't know.
Since this fixes an ICE, and if the constants are indeed used, these 2 tests will turn into a hard error, I thought I'd open the PR anyways. And if ```@RalfJung``` you know of a way I could manage that (if you think that these tests are worth checking that the `throw_ub_format!` does indeed create const-ub errors as we expect) I'd be grateful.
For that reason, r? ```@RalfJung``` and cc ```@oli-obk.```
Do not suggest ampmut if rhs is already mutable
Removes invalid suggestion in #85765, although it should highlight the user type instead of the local variable.
Looking at the comments of this line:
84b1005bfd/compiler/rustc_mir_build/src/build/matches/mod.rs (L2107)
It was intentionally set to `None`, causing it to highlight the local variable instead. I am not sure if I will be able to fix it.
Fixes#85765
Fix some diagnostic issues with const_generics_defaults feature gate
This PR makes a few changes:
- print out const param defaults in "lifetime ordering" errors rather than discarding them
- update `is_simple_text` to account for const params when checking if a type has no generics, this was causing a note to be failed to add to an error message
- fixes some diagnostic wording that incorrectly said there was ordering restrictions between type/const params despite the `const_generics_defaults` feature gate is active
Don't use a generator for BoxedResolver
The generator is non-trivial and requires unsafe code anyway. Using regular unsafe code without a generator is much easier to follow.
Based on #85810 as it touches rustc_interface too.
