`TyCtxt::short_string` ensures that user visible type paths aren't overwhelming on the terminal output, and properly saves the long name to disk as a side-channel. We already use these throughout the compiler and have been using them as needed when users find cases where the output is verbose. This is a proactive search of some cases to use `short_string`.
We add support for shortening the path of "trait path only".
Every manual use of `short_string` is a bright marker that that error should be using structured diagnostics instead (as they have proper handling of long types without the maintainer having to think abou tthem).
When we don't actually print out a shortened type we don't need the "use `--verbose`" note.
On E0599 show type identity to avoid expanding the receiver's generic parameters.
Unify wording on `long_ty_path` everywhere.
lower pattern bindings in the order they're written and base drop order on primary bindings' order
To fixrust-lang/rust#142163, this PR does two things:
- Makes match arms base their drop order on the first sub-branch instead of the last sub-branch. Together with the second change, this makes bindings' drop order correspond to the relative order of when each binding first appears (i.e. the order of the "primary" bindings).
- Lowers pattern bindings in the order they're written (still treating the right-hand side of a ``@`` as coming before the binding on the left). In each sub-branch of a match arm, this is the order that would be obtained if the or-alternatives chosen in that sub-branch were inlined into the arm's pattern. This both affects drop order (making bindings in or-patterns not be dropped first) and fixes the issue in [this test](2a023bf80a/tests/ui/pattern/bindings-after-at/bind-by-copy-or-pat.rs) from rust-lang/rust#121716.
My approach to the second point is admittedly a bit trickier than may be necessary. To avoid passing around a counter when building `FlatPat`s, I've instead added just enough information to recover the original structure of the pattern's bindings from a `MatchTreeSubBranch`'s path through the `Candidate` tree. Some alternatives:
- We could use a counter, then sort bindings by their ordinals when making `MatchTreeSubBranch`es.
- I'd like to experiment with always merging sub-candidates and removing `test_remaining_match_pairs_after_or`; that would require lowering bindings and guards in a different way. That makes it a bigger change too, though, so I figure it might be simplest to start here.
- For a very big change, we could track which or-alternatives succeed at runtime to base drop order on the binding order in the particular alternatives matched.
This is a breaking change. It will need a crater run, language team sign-off, and likely updates to the Reference.
This will conflict with rust-lang/rust#143376 and probably also rust-lang/rust#143028, so they shouldn't be merged at the same time.
r? `@matthewjasper` or `@Nadrieril`
emit `StorageLive` and schedule `StorageDead` for `let`-`else`'s bindings after matching
This PR removes special handling of `let`-`else`, so that `StorageLive`s are emitted and `StorageDead`s are scheduled only after pattern-matching has succeeded. This means `StorageDead`s will no longer appear for all of its bindings on the `else` branch (because they're not live yet) and its drops&`StorageDead`s will happen together like they do elsewhere, rather than having all drops first, then all `StorageDead`s.
This fixesrust-lang/rust#142056, and is therefore a breaking change. I believe it'll need a crater run and a T-lang nomination/fcp thereafter. Specifically, this makes drop-checking slightly more restrictive for `let`-`else` to match the behavior of other variable binding forms. An alternative approach could be to change the relative order of drops and `StorageDead`s for other binding forms to make drop-checking more permissive, but making that consistent would be a significantly more involved change.
r? mir
cc `````@dingxiangfei2009`````
`````@rustbot````` label +T-lang +needs-crater
Type lowering can give non-fatal errors that dropck then uses to suppress its own errors. Assume this is the cases when we can't find the error in borrowck.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
This changes the remaining span for the cast, because the new `Cast`
category has a higher priority (lower `Ord`) than the old `Coercion`
category, so we no longer report the region error for the "unsizing"
coercion from `*const Trait` to itself.
This is a aspect of Rust that frequently trips up people who are not
aware of it yet. This diagnostic attempts to explain what's happening
and why the lifetime constraint, that was never mentioned in the source,
arose.
Tweak spans for self arg, fix borrow suggestion for signature mismatch
1. Adjust a suggestion message that was annoying me
2. Fix#112503 by recording the right spans for the `self` part of the `&self` 0th argument
3. Remove the suggestion for adjusting a trait signature on type mismatch, bc that's gonna probably break all the other impls of the trait even if it fixes its one usage 😅
