Rollup merge of #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.

#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`

2 files changed, 0 insertions, 16 deletions

diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs
index cc09a094688..a086d89b933 100644
--- a/compiler/rustc_infer/src/infer/at.rs
+++ b/compiler/rustc_infer/src/infer/at.rs
@@ -87,7 +87,6 @@ impl<'tcx> InferCtxt<'tcx> {
             reported_signature_mismatch: self.reported_signature_mismatch.clone(),
             tainted_by_errors: self.tainted_by_errors.clone(),
             err_count_on_creation: self.err_count_on_creation,
-            stashed_err_count_on_creation: self.stashed_err_count_on_creation,
             universe: self.universe.clone(),
             intercrate,
             next_trait_solver: self.next_trait_solver,
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index d7e16488508..6f52ded3551 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -306,12 +306,6 @@ pub struct InferCtxt<'tcx> {
     // FIXME(matthewjasper) Merge into `tainted_by_errors`
     err_count_on_creation: usize,
 
-    /// Track how many errors were stashed when this infcx is created.
-    /// Used for the same purpose as `err_count_on_creation`, even
-    /// though it's weaker because the count can go up and down.
-    // FIXME(matthewjasper) Merge into `tainted_by_errors`
-    stashed_err_count_on_creation: usize,
-
     /// What is the innermost universe we have created? Starts out as
     /// `UniverseIndex::root()` but grows from there as we enter
     /// universal quantifiers.
@@ -717,7 +711,6 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
             reported_signature_mismatch: Default::default(),
             tainted_by_errors: Cell::new(None),
             err_count_on_creation: tcx.dcx().err_count_excluding_lint_errs(),
-            stashed_err_count_on_creation: tcx.dcx().stashed_err_count(),
             universe: Cell::new(ty::UniverseIndex::ROOT),
             intercrate,
             next_trait_solver,
@@ -1274,14 +1267,6 @@ impl<'tcx> InferCtxt<'tcx> {
             let guar = self.dcx().has_errors().unwrap();
             self.set_tainted_by_errors(guar);
             Some(guar)
-        } else if self.dcx().stashed_err_count() > self.stashed_err_count_on_creation {
-            // Errors stashed since this infcx was made. Not entirely reliable
-            // because the count of stashed errors can go down. But without
-            // this case we get a moderate number of uninteresting and
-            // extraneous "type annotations needed" errors.
-            let guar = self.dcx().delayed_bug("tainted_by_errors: stashed bug awaiting emission");
-            self.set_tainted_by_errors(guar);
-            Some(guar)
         } else {
             None
         }