avoid promoting division, modulo and indexing operations that could fail
For division, `x / y` will still be promoted if `y` is a non-zero integer literal; however, `1/(1+1)` will not be promoted any more.
While at it, also see if we can reject promoting floating-point arithmetic (which are [complicated](https://github.com/rust-lang/unsafe-code-guidelines/issues/237) so maybe we should not promote them).
This will need a crater run to see if there's code out there that relies on these things being promoted.
If we can land this, promoteds in `fn`/`const fn` cannot fail to evaluate any more, which should let us do some simplifications in codegen/Miri!
Cc https://github.com/rust-lang/rfcs/pull/3027
Fixes https://github.com/rust-lang/rust/issues/61821
r? `@oli-obk`
Improve diagnostics when parsing angle args
https://github.com/rust-lang/rust/pull/79266 introduced parsing of generic arguments in associated type constraints, this however resulted in possibly very confusing error messages in cases in which closing angle brackets were missing such as in `Vec<(u32, _, _) = vec![]`, which outputs an incorrectly parsed equality constraint error, as noted by `@cynecx.`
This PR tries to provide better error messages in such cases.
r? `@petrochenkov`
Refactor token collection to capture trailing token immediately
Split out from https://github.com/rust-lang/rust/pull/80689 - when we start capturing more information about attribute targets, we'll need to know in advance if we're capturing a trailing token or not.
r? `@ghost`
Gracefully handle loop labels missing leading `'` in different positions
Fix#81192.
* Account for labels when suggesting `loop` instead of `while true`
* Suggest `'a` when given `a` only when appropriate
* Add loop head span to hir
* Tweak error for invalid `break expr`
* Add more misspelled label tests
* Avoid emitting redundant "unused label" lint
* Parse loop labels missing a leading `'`
Each commit can be reviewed in isolation.
Fix formatting for removed lints
- Don't add backticks for the reason a lint was removed. This is almost
never a code block, and when it is the backticks should be in the reason
itself.
- Don't assume clippy is the only tool that needs to be checked for
backwards compatibility
I split this out of https://github.com/rust-lang/rust/pull/80527/ because it kept causing tests to fail, and it's a good change to have anyway.
r? `@flip1995`
When encountering a name `a` that isn't resolved, but a label `'a` is
found in the current ribs, only suggest `'a` if this name is the value
expression of a `break` statement.
Solve FIXME.
Force token collection to run when parsing nonterminals
Fixes#81007
Previously, we would fail to collect tokens in the proper place when
only builtin attributes were present. As a result, we would end up with
attribute tokens in the collected `TokenStream`, leading to duplication
when we attempted to prepend the attributes from the AST node.
We now explicitly track when token collection must be performed due to
nomterminal parsing.
Fix ICE in mir when evaluating SizeOf on unsized type
Not quite ready yet. This tries to fix#80742 as discussed on [Zulip topic][1],
by using `delay_span_bug`.
I don't understand what `delay_span_bug` does. It seems like my error message
is never used. With this patch, in this program:
```rust
#![allow(incomplete_features)]
#![feature(const_evaluatable_checked)]
#![feature(const_generics)]
use std::fmt::Debug;
use std::marker::PhantomData;
use std::mem::size_of;
struct Inline<T>
where
[u8; size_of::<T>() + 1]: ,
{
_phantom: PhantomData<T>,
buf: [u8; size_of::<T>() + 1],
}
impl<T> Inline<T>
where
[u8; size_of::<T>() + 1]: ,
{
pub fn new(val: T) -> Inline<T> {
todo!()
}
}
fn main() {
let dst = Inline::<dyn Debug>::new(0); // line 27
}
```
these errors are printed, both for line 27 (annotated line above):
- "no function or associated item named `new` found for struct `Inline<dyn
Debug>` in the current scope"
- "the size for values of type `dyn Debug` cannot be known at compilation time"
Second error makes sense, but I'm not sure about the first one and why it's
even printed.
Finally, I'm not sure about the span passing in `const_eval`.
[1]: https://rust-lang.zulipchat.com/#narrow/stream/269128-miri/topic/Help.20fixing.20.2380742
Fixes#81007
Previously, we would fail to collect tokens in the proper place when
only builtin attributes were present. As a result, we would end up with
attribute tokens in the collected `TokenStream`, leading to duplication
when we attempted to prepend the attributes from the AST node.
We now explicitly track when token collection must be performed due to
nomterminal parsing.
Serialize dependency graph directly from DepGraph
Reduce memory usage by serializing dep graph directly from `DepGraph`,
rather than copying it into `SerializedDepGraph` and serializing that.
Fix `unused_unsafe` label with `unsafe_block_in_unsafe_fn
Previously, the following code:
```rust
#![feature(unsafe_block_in_unsafe_fn)]
unsafe fn foo() {
unsafe { unsf() }
}
unsafe fn unsf() {}
```
Would give the following warning:
```
warning: unnecessary `unsafe` block
--> src/lib.rs:4:5
|
4 | unsafe { unsf() }
| ^^^^^^ unnecessary `unsafe` block
|
= note: `#[warn(unused_unsafe)]` on by default
```
which doesn't point out that the block is in an `unsafe fn`.
Tracking issue: #71668
cc #79208
don't suggest erroneous trailing comma after `..`
In #76612, suggestions were added for missing fields in patterns. However, the suggestions are being inserted just at the end
of the last field in the pattern—before any trailing comma after the last field. This resulted in the "if you don't care about missing fields" suggestion to recommend code with a trailing comma after the field ellipsis (`..,`), which is actually not legal ("`..` must be at the end and cannot have a trailing comma")!
Incidentally, the doc-comment on `error_unmentioned_fields` was using `you_cant_use_this_field` as an example field name (presumably copy-paste inherited from the description of Issue #76077), but the present author found this confusing, because unmentioned fields aren't necessarily unusable.
The suggested code in the diff this commit introduces to `destructuring-assignment/struct_destructure_fail.stderr` doesn't work, but it didn't work beforehand, either (because of the "found reserved identifier `_`" thing), so you can't really call it a regression; it could be fixed in a separate PR.
Resolves#78511.
r? `@davidtwco` or `@estebank`
Stability oddity with const intrinsics
cc `@RalfJung`
In https://github.com/rust-lang/rust/pull/80699#discussion_r551495670 `@usbalbin` realized we accepted some intrinsics as `const` without a `#[rustc_const_(un)stable]` attribute. I did some digging, and that example works because intrinsics inherit their stability from their parents... including `#[rustc_const_(un)stable]` attributes. While we may want to fix that (not sure, wasn't there just a MCPed PR that caused this on purpose?), we definitely want tests for it, thus this PR adding tests and some fun tracing statements.
