Previously, any associated function could have `~const` trait bounds on
generic parameters, which could lead to ICEs when these bounds were used
on associated functions of non-`#[const_trait] trait` or
non-`impl const` blocks.
Includes changes as per @fee1-dead's comments in #116210.
Rollup of 6 pull requests
Successful merges:
- #115770 (Match on elem first while building move paths)
- #115999 (Capture scrutinee of if let guards correctly)
- #116056 (Make unsized casts illegal)
- #116061 (Remove TaKO8Ki from review rotation)
- #116062 (Change `start` to `#[start]` in some diagnosis)
- #116067 (Open the FileEncoder file for reading and writing)
r? `@ghost`
`@rustbot` modify labels: rollup
[breaking change] Validate crate name in `--extern` [MCP 650]
Reject non-ASCII-identifier crate names passed to the CLI option `--extern` (`rustc`, `rustdoc`).
Implements [MCP 650](https://github.com/rust-lang/compiler-team/issues/650) (except that we only allow ASCII identifiers not arbitrary Rust identifiers).
Fixes#113035.
[As mentioned on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-t-compiler.2Fmajor-changes/topic/Disallow.20non-identifier-valid.20--extern.20cr.E2.80.A6.20compiler-team.23650/near/376826988), doing a crater run probably doesn't make sense since it wouldn't yield anything. Most users don't interact with `rustc` directly but only ever through Cargo which always passes a valid crate name to `--extern` when it invokes `rustc` and `rustdoc`. In any case, the user wouldn't be able to use such a crate name in the source code anyway.
Note that I'm not using [`rustc_session::output::validate_crate_name`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_session/output/fn.validate_crate_name.html) (used for `--crate-name` and `#![crate_name]`) since the latter doesn't reject non-ASCII crate names and ones that start with a digit.
As an aside, I've also thought about getting rid of `validate_crate_name` entirely in a separate PR (with another MCP) in favor of `is_ascii_ident` to reject more weird `--crate-name`s, `#![crate_name]`s and file names but I think that would lead to a lot of actual breakage, namely because of file names starting with a digit. In `tests/ui` 9 tests would be impacted for example.
CC `@estebank`
r? `@est31`
Fallback effects even if types also fallback
`||` is short circuiting, so if we do ty/int var fallback, we *don't* do effect fallback 😸
r? `@fee1-dead` or `@oli-obk`
Fixes#115791Fixes#115842
Improve invalid let expression handling
- Move all of the checks for valid let expression positions to parsing.
- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a valid location.
- Suppress some later errors and MIR construction for invalid let expressions.
- Fix a (drop) scope issue that was also responsible for #104172.
Fixes#104172Fixes#104868
- Add doc comment to new type
- Restore "only supported directly in conditions of `if` and `while` expressions" note
- Rename variant with clearer name
Previously some invalid let expressions would result in both a feature
error and a parsing error. Avoid this and ensure that we only emit the
parsing error when this happens.
There was an incomplete version of the check in parsing and a second
version in AST validation. This meant that some, but not all, invalid
uses were allowed inside macros/disabled cfgs. It also means that later
passes have a hard time knowing when the let expression is in a valid
location, sometimes causing ICEs.
- Add a field to ExprKind::Let in AST/HIR to mark whether it's in a
valid location.
- Suppress later errors and MIR construction for invalid let
expressions.
Lower `Or` pattern without allocating place
cc `@azizghuloum` `@cjgillot`
Related to #111583 and #111644
While reviewing #111644, it occurs to me that while we directly lower conjunctive predicates, which are connected with `&&`, into the desirable control flow, today we don't directly lower the disjunctive predicates, which are connected with `||`, in the similar fashion. Instead, we allocate a place for the boolean temporary to hold the result of evaluating the `||` expression.
Usually I would expect optimization at later stages to "inline" the evaluation of boolean predicates into simple CFG, but #111583 is an example where `&&` is failing to be optimized away and the assembly shows that both the expensive operands are evaluated. Therefore, I would like to make a small change to make the CFG a bit more straight-forward without invoking the `as_temp` machinery, and plus avoid allocating the place to hold the boolean result as well.
On the following example, point at `String` instead of the whole type:
```
error[E0277]: the trait bound `String: Copy` is not satisfied
--> $DIR/own-bound-span.rs:14:24
|
LL | let _: <S as D>::P<String>;
| ^^^^^^ the trait `Copy` is not implemented for `String`
|
note: required by a bound in `D::P`
--> $DIR/own-bound-span.rs:4:15
|
LL | type P<T: Copy>;
| ^^^^ required by this bound in `D::P`
```
Fix #[inline(always)] on closures with target feature 1.1
Fixes#108655. I think this is the most obvious solution that isn't overly complicated. The comment includes more justification, but I think this is likely better than demoting the `#[inline(always)]` to `#[inline]`, since existing code is unaffected.
Better diagnostics for dlltool errors.
When dlltool fails, show the full command that was executed. In particular, llvm-dlltool is not very helpful, printing a generic usage message rather than what actually went wrong, so stdout and stderr aren't of much use when troubleshooting.
When dlltool fails, show the full command that was executed. In
particular, llvm-dlltool is not very helpful, printing a generic usage
message rather than what actually went wrong, so stdout and stderr
aren't of much use when troubleshooting.
(re-)tighten sourceinfo span of adjustments in MIR
Diagnostics rely on the spans of MIR statements being (approximately) correct in order to give suggestions relative to that span (i.e. `shrink_to_hi` and `shrink_to_lo`).
I discovered that we're *intentionally* lowering THIR exprs with their parent expr's span if they come from adjustments that are due to a parent expression. While I understand why that may be desirable to demonstrate the relationship of an adjustment and the expression that requires it, it leads to
1. very verbose borrowck output
2. incorrect spans for suggestions
Some diagnostics get around that by giving suggestions relative to other spans we've collected during MIR lowering, such as the span of the method's identifier (e.g. `name` in `.name()`), but this doesn't work too well when things come from desugaring.
I assume it also has lead to numerous tweaks and complications to diagnostics code down the road, which this PR doesn't necessarily aim to fix but may open the gates to fixing later... The last three commits are simplifications due to the fact that we can assume that the move span actually points to what is being moved (and a test).
This regressed in #89110, which was debated somewhat in #90286. cc `@Aaron1011` who originally made this change.
r? diagnostics
Fixes#113547Fixes#111016
Revert the lexing of `c"…"` string literals
Fixes \[after beta-backport\] #113235.
Further progress is tracked in #113333.
This PR *manually* reverts parts of #108801 (since a git-revert would've been too coarse-grained & messy)
and git-reverts #111647.
CC `@fee1-dead` (#108801) `@klensy` (#111647)
r? `@compiler-errors`
`@rustbot` label F-c_str_literals beta-nominated
