Count stashed errors again by nnethercote · Pull Request #121669

Count stashed errors again by nnethercote · Pull Request #121669 · rust-lang/rust

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Feb 27, 2024

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Feb 28, 2024

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.)

This gives one extra error message on two tests, 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.)

Stashed errors used to be counted as errors, but could then be
cancelled, leading to `ErrorGuaranteed` soundness holes. rust-lang#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 rust-lang#121451.
Fixes rust-lang#121477.
Fixes rust-lang#121504.
Fixes rust-lang#121508.

Seems wise, since it shouldn't proceed in that case.

I removed it in rust-lang#121206 because I thought thought it wasn't necessary.
But then I had to add an `emit_stashed_diagnostics` call elsewhere in
rustfmt to avoid the assertion failure (which took two attempts to get
right, rust-lang#121487 and rust-lang#121615), and now there's an assertion failure in
clippy as well (rust-lang/rust-clippy#12364).

So this commit just reinstates the call in `DiagCtxtInner::drop`. It
also reverts the rustfmt changes from rust-lang#121487 and rust-lang#121615, though it
keeps the tests added for those PRs.

bors added S-waiting-on-bors

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Feb 29, 2024

bors added a commit to rust-lang-ci/rust that referenced this pull request

Feb 29, 2024

…iaskrgr

Rollup of 5 pull requests

Successful merges:

 - rust-lang#110543 (Make `ReentrantLock` public)
 - rust-lang#121689 ([rustdoc] Prevent inclusion of whitespace character after macro_rules ident)
 - rust-lang#121724 (Use `LitKind::Err` for malformed floats)
 - rust-lang#121735 (pattern analysis: Don't panic when encountering unexpected constructor)
 - rust-lang#121743 (Opportunistically resolve regions when processing region outlives obligations)

Failed merges:

 - rust-lang#121326 (Detect empty leading where clauses on type aliases)
 - rust-lang#121416 (Improve error messages for generics with default parameters)
 - rust-lang#121669 (Count stashed errors again)
 - rust-lang#121723 (Two diagnostic things)

r? `@ghost`
`@rustbot` modify labels: rollup

bors added a commit to rust-lang-ci/rust that referenced this pull request

Feb 29, 2024

…llaumeGomez

Rollup of 7 pull requests

Successful merges:

 - rust-lang#119748 (Increase visibility of `join_path` and `split_paths`)
 - rust-lang#120820 (Enable CMPXCHG16B, SSE3, SAHF/LAHF and 128-bit Atomics (in nightly) in Windows x64)
 - rust-lang#121000 (pattern_analysis: rework how we hide empty private fields)
 - rust-lang#121376 (Skip unnecessary comparison with half-open range patterns)
 - rust-lang#121596 (Use volatile access instead of `#[used]` for `on_tls_callback`)
 - rust-lang#121669 (Count stashed errors again)
 - rust-lang#121783 (Emitter cleanups)

r? `@ghost`
`@rustbot` modify labels: rollup

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

Feb 29, 2024

Rollup merge of rust-lang#121669 - nnethercote:count-stashed-errs-again, r=estebank

Count stashed errors again

Stashed diagnostics are such a pain. Their "might be emitted, might not" semantics messes with lots of things.

rust-lang#120828 and rust-lang#121206 made some big changes to how they work, improving some things, but still leaving some problems, as seen by the issues caused by rust-lang#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`

flip1995 pushed a commit to flip1995/rust that referenced this pull request

Mar 7, 2024

…in, r=estebank

Count stashed errors again

Stashed diagnostics are such a pain. Their "might be emitted, might not" semantics messes with lots of things.

rust-lang#120828 and rust-lang#121206 made some big changes to how they work, improving some things, but still leaving some problems, as seen by the issues caused by rust-lang#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`

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Jan 12, 2025

…ng, r=chenyukang

Remove a bunch of diagnostic stashing that doesn't do anything

rust-lang#121669 removed a bunch of conditional diagnostic stashing/canceling, but left around the `steal` calls which just emitted the error eagerly instead of canceling the diagnostic. I think that these no-op `steal` calls don't do much and are confusing to encounter, so let's remove them.

The net effect is:
1. We emit more duplicated errors, since stashing has the side effect of duplicating diagnostics. This is not a big deal, since outside of `-Zdeduplicate-diagnostics=no`, the errors are already being deduplicated by the compiler.
2. It changes the order of diagnostics, since we're no longer stashing and then later stealing the errors. I don't think this matters much for the changes that the UI test suite manifests, and it makes these errors less order dependent.

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

Jan 12, 2025

Rollup merge of rust-lang#135378 - compiler-errors:unnecessary-stashing, r=chenyukang

Remove a bunch of diagnostic stashing that doesn't do anything

rust-lang#121669 removed a bunch of conditional diagnostic stashing/canceling, but left around the `steal` calls which just emitted the error eagerly instead of canceling the diagnostic. I think that these no-op `steal` calls don't do much and are confusing to encounter, so let's remove them.

The net effect is:
1. We emit more duplicated errors, since stashing has the side effect of duplicating diagnostics. This is not a big deal, since outside of `-Zdeduplicate-diagnostics=no`, the errors are already being deduplicated by the compiler.
2. It changes the order of diagnostics, since we're no longer stashing and then later stealing the errors. I don't think this matters much for the changes that the UI test suite manifests, and it makes these errors less order dependent.