Count stashed errors again #121669

nnethercote · 2024-02-27T06:17:05Z

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

rustbot · 2024-02-27T06:17:13Z

r? @estebank

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rustbot · 2024-02-27T06:17:15Z

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

compiler/rustc_middle/src/ty/mod.rs

src/tools/clippy/tests/ui/unreachable-array-or-slice.rs

estebank

The code and output changes look reasonable to me. Left some nitpicks, but r=me on the approach.

estebank · 2024-02-27T18:18:31Z

compiler/rustc_privacy/src/lib.rs

-                self.tcx.dcx().span_delayed_bug(expr.span, "no adt_def for expression");
-                return;
-            };
+            let adt = self.typeck_results().expr_ty(expr).ty_adt_def().unwrap();


Slightly concerned that this will lead to an ICE that used not to happen (span_delayed_bug has been the go-to solution for "this is invalid state but other errors will likely have been emitted so an ICE isn't necessary).

It's just reverting to what was there before #121482.

estebank · 2024-02-27T18:20:05Z

compiler/rustc_middle/src/ty/mod.rs

+        // We used to cancel here for slightly better error messages, but
+        // cancelling stashed diagnostics is no longer allowed because it
+        // causes problems when tracking whether errors have actually
+        // occurred.
+        tcx.sess.dcx().try_steal_modify_and_emit_err(
+            tcx.def_span(opaque_def_id),
+            StashKey::OpaqueHiddenTypeMismatch,
+            |_err| {},
+        );


This change is fine.

estebank · 2024-02-27T18:21:20Z

compiler/rustc_lint/src/array_into_iter.rs

-            {
-                return;
-            }
+            let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();


I'm very weary of .unwrap() in the compiler. I've had cases where I leaned on it and later changes caused my expectations to not be met.

And this is just reverting to what was there before #121586.

I understand the purpose of span_delayed_bug, but it shouldn't be used on genuinely unreachable code paths, right? I don't know if you saw #121208 where I deliberately changed a bunch of definitely/probably/possibly unreachable span_delayed_bug calls to span_bug... some of them were found with subsequent fuzzing to be reachable, which means we got test cases for those paths.

nnethercote · 2024-02-27T21:28:33Z

I have updated to move the clippy test. I haven't made any other changes, not sure if my responses to the other comments will satisfy the reviewers.

(And apologies for messing up the syntax on the review request in the original description, it was meant to be for @oli-obk, but luck would have it that @estebank is a good reviewer for this PR as well.)

rustbot · 2024-02-28T02:09:23Z

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

nnethercote · 2024-02-28T02:10:46Z

I added one more commit, reinstating the emit_stashed_diagnostics call in DiagCtxtInner::drop, to fix all the assertion failures that we were getting (details in the commit message). That should fix all the problems that #121206 caused, I hope.

oli-obk · 2024-02-28T06:47:39Z

@bors r=estebank

fmease · 2024-02-28T19:35:01Z

@bors r=estebank

bors · 2024-02-28T19:35:04Z

📌 Commit 1c5d1c7 has been approved by estebank

It is now in the queue for this repository.

bors · 2024-02-28T23:59:16Z

☔ The latest upstream changes (presumably #121489) made this pull request unmergeable. Please resolve the merge conflicts.

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.

This undoes the changes from rust-lang#121482 and rust-lang#121586, now that stashed errors will trigger more early aborts.

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.

nnethercote · 2024-02-29T00:17:15Z

I rebased.

@bors r=estebank

bors · 2024-02-29T00:17:17Z

📌 Commit 82961c0 has been approved by estebank

It is now in the queue for this repository.

…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

…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

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`

…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`

rustbot assigned estebank Feb 27, 2024

oli-obk reviewed Feb 27, 2024

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nnethercote force-pushed the count-stashed-errs-again branch from 7addae0 to 21ce4d1 Compare February 27, 2024 21:27

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nnethercote force-pushed the count-stashed-errs-again branch from 21ce4d1 to 759785b Compare February 27, 2024 23:21

fmease closed this Feb 28, 2024

fmease reopened this Feb 28, 2024

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 28, 2024

nnethercote mentioned this pull request Feb 28, 2024

ICE: assertion failed: self.stashed_diagnostics.is_empty() rust-lang/rust-clippy#12364

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matthiaskrgr mentioned this pull request Feb 28, 2024

Rollup of 5 pull requests #121770

Merged

nnethercote mentioned this pull request Feb 28, 2024

ICE: sty: range end index 18446744073709551615 out of range for slice of length 0 #121769

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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Feb 28, 2024

nnethercote added 6 commits February 29, 2024 11:05

Don't cancel stashed TraitMissingMethod errors.

ec25d6d

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.)

Mark some once-again-unreachable paths as unreachable.

b4e9f93

This undoes the changes from rust-lang#121482 and rust-lang#121586, now that stashed errors will trigger more early aborts.

Stop miri if delayed bugs are present.

9aff357

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

nnethercote force-pushed the count-stashed-errs-again branch from 1c5d1c7 to 82961c0 Compare February 29, 2024 00:16

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Feb 29, 2024

GuillaumeGomez mentioned this pull request Feb 29, 2024

Rollup of 7 pull requests #121804

Merged

bors merged commit a5945b5 into rust-lang:master Feb 29, 2024
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rustbot added this to the 1.78.0 milestone Feb 29, 2024

nnethercote deleted the count-stashed-errs-again branch February 29, 2024 20:54

matthiaskrgr mentioned this pull request Mar 19, 2024

ICE: rustc_privacy None #122736

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Count stashed errors again #121669

Count stashed errors again #121669

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Count stashed errors again #121669

Count stashed errors again #121669

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