Count stashed errors again
Stashed diagnostics are such a pain. Their "might be emitted, might not" semantics messes with lots of things.
#120828 and #121206 made some big changes to how they work, improving some things, but still leaving some problems, as seen by the issues caused by #121206. This PR aims to fix all of them by restricting them in a way that eliminates the "might be emitted, might not" semantics while still allowing 98% of their benefit. Details in the individual commit logs.
r? `@oli-obk`
Skip unnecessary comparison with half-open range patterns
This is the last remaining detail in the implementation of half-open range patterns. Until now, a half-open range pattern like `10..` was converted to `10..T::MAX` before lowering to MIR, which generated an extra pointless comparison. With this PR we don't generate it.
Stashed errors used to be counted as errors, but could then be
cancelled, leading to `ErrorGuaranteed` soundness holes. #120828 changed
that, closing the soundness hole. But it introduced other difficulties
because you sometimes have to account for pending stashed errors when
making decisions about whether errors have occured/will occur and it's
easy to overlook these.
This commit aims for a middle ground.
- Stashed errors (not warnings) are counted immediately as emitted
errors, avoiding the possibility of forgetting to consider them.
- The ability to cancel (or downgrade) stashed errors is eliminated, by
disallowing the use of `steal_diagnostic` with errors, and introducing
the more restrictive methods `try_steal_{modify,replace}_and_emit_err`
that can be used instead.
Other things:
- `DiagnosticBuilder::stash` and `DiagCtxt::stash_diagnostic` now both
return `Option<ErrorGuaranteed>`, which enables the removal of two
`delayed_bug` calls and one `Ty::new_error_with_message` call. This is
possible because we store error guarantees in
`DiagCtxt::stashed_diagnostics`.
- Storing the guarantees also saves us having to maintain a counter.
- Calls to the `stashed_err_count` method are no longer necessary
alongside calls to `has_errors`, which is a nice simplification, and
eliminates two more `span_delayed_bug` calls and one FIXME comment.
- Tests are added for three of the four fixed PRs mentioned below.
- `issue-121108.rs`'s output improved slightly, omitting a non-useful
error message.
Fixes#121451.
Fixes#121477.
Fixes#121504.
Fixes#121508.
This gives one extra error message on one test, but is necessary to fix
bigger problems caused by the cancellation of stashed errors.
(Note: why not just avoid stashing altogether? Because that resulted in
additional output changes.)
Diagnostic renaming
Renaming various diagnostic types from `Diagnostic*` to `Diag*`. Part of https://github.com/rust-lang/compiler-team/issues/722. There are more to do but this is enough for one PR.
r? `@davidtwco`
Split rustc_type_ir to avoid rustc_ast from depending on it
unblocks #121576
and resolves a FIXME in `rustc_ast`'s `Cargo.toml`
The new crate is tiny, but it will get bigger in #121576
Delayed bug audit
I went through all the calls to `delayed_bug` and `span_delayed_bug` and found a few places where they could be avoided.
r? `@compiler-errors`
Add `StructurallyRelateAliases` to allow instantiating infer vars with rigid aliases.
Change `instantiate_query_response` to be infallible in the new solver. This requires canonicalization to not hide any information used by the query, so weaken
universe compression. It also modifies `term_is_fully_unconstrained` to allow
region inference variables in a higher universe.
mark `min_exhaustive_patterns` as complete
This is step 1 and 2 of my [proposal](https://github.com/rust-lang/rust/issues/119612#issuecomment-1918097361) to move `min_exhaustive_patterns` forward. The vast majority of in-tree use cases of `exhaustive_patterns` are covered by `min_exhaustive_patterns`. There are a few cases that still require `exhaustive_patterns` in tests and they're all behind references.
r? ``@ghost``
region unification: update universe of region vars
necessary for #119106. see inline comment for why this is necessary
r? `@compiler-errors` `@BoxyUwU`
Provide suggestions through `rustc_confusables` annotations
Help with common API confusion, like asking for `push` when the data structure really has `append`.
```
error[E0599]: no method named `size` found for struct `Vec<{integer}>` in the current scope
--> $DIR/rustc_confusables_std_cases.rs:17:7
|
LL | x.size();
| ^^^^
|
help: you might have meant to use `len`
|
LL | x.len();
| ~~~
help: there is a method with a similar name
|
LL | x.resize();
| ~~~~~~
```
Fix#59450 (we can open subsequent tickets for specific cases).
Fix#108437:
```
error[E0599]: `Option<{integer}>` is not an iterator
--> f101.rs:3:9
|
3 | opt.flat_map(|val| Some(val));
| ^^^^^^^^ `Option<{integer}>` is not an iterator
|
::: /home/gh-estebank/rust/library/core/src/option.rs:571:1
|
571 | pub enum Option<T> {
| ------------------ doesn't satisfy `Option<{integer}>: Iterator`
|
= note: the following trait bounds were not satisfied:
`Option<{integer}>: Iterator`
which is required by `&mut Option<{integer}>: Iterator`
help: you might have meant to use `and_then`
|
3 | opt.and_then(|val| Some(val));
| ~~~~~~~~
```
On type error of method call arguments, look at confusables for suggestion. Fix#87212:
```
error[E0308]: mismatched types
--> f101.rs:8:18
|
8 | stuff.append(Thing);
| ------ ^^^^^ expected `&mut Vec<Thing>`, found `Thing`
| |
| arguments to this method are incorrect
|
= note: expected mutable reference `&mut Vec<Thing>`
found struct `Thing`
note: method defined here
--> /home/gh-estebank/rust/library/alloc/src/vec/mod.rs:2025:12
|
2025 | pub fn append(&mut self, other: &mut Self) {
| ^^^^^^
help: you might have meant to use `push`
|
8 | stuff.push(Thing);
| ~~~~
```
Make --verbose imply -Z write-long-types-to-disk=no
When shortening the type it is necessary to take into account the `--verbose` flag, if it is activated, we must always show the entire type and not write it in a file.
Fixes: https://github.com/rust-lang/rust/issues/119130
Convert `delayed_bug`s to `bug`s.
I have a suspicion that quite a few delayed bug paths are impossible to reach, so I did an experiment.
I converted every `delayed_bug` to a `bug`, ran the full test suite, then converted back every `bug` that was hit. A surprising number were never hit.
This is too dangerous to merge. Increased coverage (fuzzing or a crater run) would likely hit more cases. But it might be useful for people to look at and think about which paths are genuinely unreachable.
r? `@ghost`
I have a suspicion that quite a few delayed bug paths are impossible to
reach, so I did an experiment.
I converted every `delayed_bug` to a `bug`, ran the full test suite,
then converted back every `bug` that was hit. A surprising number were
never hit.
The next commit will convert some more back, based on human judgment.
Overhaul `Diagnostic` and `DiagnosticBuilder`
Implements the first part of https://github.com/rust-lang/compiler-team/issues/722, which moves functionality and use away from `Diagnostic`, onto `DiagnosticBuilder`.
Likely follow-ups:
- Move things around, because this PR was written to minimize diff size, so some things end up in sub-optimal places. E.g. `DiagnosticBuilder` has impls in both `diagnostic.rs` and `diagnostic_builder.rs`.
- Rename `Diagnostic` as `DiagInner` and `DiagnosticBuilder` as `Diag`.
r? `@davidtwco`
When shortening the type it is necessary to take into account the
`--verbose` flag, if it is activated, we must always show the entire
type and not write it in a file.
Fixes: https://github.com/rust-lang/rust/issues/119130
Allow AST and HIR visitors to return `ControlFlow`
Alternative to #108598.
Since rust-lang/libs-team#187 was rejected, this implements our own version of the `Try` trait (`VisitorResult`) and the `try` macro (`try_visit`). Since this change still allows visitors to return `()`, no changes have been made to the existing ones. They can be done in a separate PR.
There are lots of functions that modify a diagnostic. This can be via a
`&mut Diagnostic` or a `&mut DiagnosticBuilder`, because the latter type
wraps the former and impls `DerefMut`.
This commit converts all the `&mut Diagnostic` occurrences to `&mut
DiagnosticBuilder`. This is a step towards greatly simplifying
`Diagnostic`. Some of the relevant function are made generic, because
they deal with both errors and warnings. No function bodies are changed,
because all the modifier methods are available on both `Diagnostic` and
`DiagnosticBuilder`.
