Make use of possibly uninitialized data [E0381] a hard error
This is one of the behaviors we no longer allow in NLL. Since it can
lead to undefined behavior, I think it's definitely worth making it a
hard error without waiting to turn off migration mode (#58781).
Closes#60450.
My ulterior motive here is making it impossible to leave variables
partially initialized across a yield (see #60889, discussion at #63035), so
tests are included for that.
cc #54987
---
I'm not sure if bypassing the buffer is a good way of doing this. We could also make a `force_errors_buffer` or similar that gets recombined with all the errors as they are emitted. But this is simpler and seems fine to me.
r? @Centril
cc @cramertj @nikomatsakis @pnkfelix @RalfJung
This is one of the behaviors we no longer allow in NLL. Since it can
lead to undefined behavior, I think it's definitely worth making it a
hard error without waiting to turn off migration mode (#58781).
Closes#60450.
My ulterior motive here is making it impossible to leave variables
partially initialized across a yield (see discussion at #63035), so
tests are included for that.
Avoid ICE when referencing desugared local binding in borrow error
To avoid leaking the names of local bindings from expressions like for loops, #60984 explicitly ignored them, but an assertion that `LocalKind::Var` *must* have a name would trigger an ICE.
Before this change, the binding generated by desugaring the for loop would leak into the diagnostic (#63027):
```
error[E0515]: cannot return value referencing local variable `__next`
--> return-local-binding-from-desugaring.rs:LL:CC
|
LL | for ref x in xs {
| ----- `__next` is borrowed here
...
LL | result
| ^^^^^^ returns a value referencing data owned by the current function
```
Ideally `LocalKind` would carry more information to more accurately explain the problem, but for now, in order to avoid the ICE (fix#63026), we accept `LocalKind::Var` without a name and produce the following output:
```
error[E0515]: cannot return value referencing local binding
--> $DIR/return-local-binding-from-desugaring.rs:30:5
|
LL | for ref x in xs {
| -- local binding introduced here
...
LL | result
| ^^^^^^ returns a value referencing data owned by the current function
```
This is just a difference from the test construction, it's ignore-compare-mode-nll and manually checks migrate/nll over edition2015/2018.
This failure is because the `migrate2015` and `migrate2018` revisions are ran with `-Zpolonius`. There is no actual difference in the errors output by NLLs and Polonius.
This is test specific to the NLL migrate mode which is irrelevant to -Z polonius.
It can't currently be encoded depending on migrate-mode and NLL/Polonius mode, so the NLL compare-mode also ignores it.
Exit arm scopes
Due to a bug in the HIR CFG construction, borrows for arm scopes were incorrectly leaking into other arms.
This PR also includes some drive-by improvements to `-Zunpretty=hir,identified` that would have been helpful while investigating this.
Closes#62107
As per issue #54985 removes the not useful suggestion to remove asterisk in
move errors. Includes minor changes to tests in the `ui` suite to account
for the removed suggestion.
Warn when ignore-tidy-linelength is present, but no lines are too long
It's easy for a `// ignore-tidy-linelength` to be added when there is a genuine need to ignore a file's line length, but then after refactoring the need is gone, but the tidy directive is not removed. This means that in the future, further editing may accidentally add unnecessarily long lines. This change forces `// ignore-tidy-linelength` to be used exactly when necessary, to make sure such changes are intentional.
Don't stop evaluating due to errors before borrow checking
r? @oli-obk
Fix#60005. Follow up to #59903. Blocked on #53708, fixing the ICE in `src/test/ui/consts/match_ice.rs`.
More restrictive 2 phase borrows - take 2
Signal lint diagnostic `mutable_borrow_reservation_conflict` when borrow-check finds a 2-phase borrow's reservation overlapping with a shared borrow.
(pnkfelix updated description)
cc #56254 , #59159
blocks PR #59114
r? @pnkfelix
cc @RalfJung @nikomatsakis
