Auto merge of #95542 - xFrednet:rfc-2383-expect-query, r=wesleywiser

Support tool lints with the `#[expect]` attribute (RFC 2383)

This PR fixes the ICE https://github.com/rust-lang/rust/issues/94953 by making the assert for converted expectation IDs conditional.

Additionally, it moves the lint expectation check into a separate query to support rustdoc and other tools. On the way, I've also added some tests to ensure that the attribute works for Clippy and rustdoc lints.

The number of changes comes from the long test file. This may look like a monster PR, this may smell like a monster PR and this may be a monster PR, but it's a harmless monster. :sauropod:

---

Closes: https://github.com/rust-lang/rust/issues/94953

cc: https://github.com/rust-lang/rust/issues/85549

r? `@wesleywiser`

cc: `@rust-lang/rustdoc`

1 files changed, 17 insertions, 6 deletions

diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index f83fa68ced0..29643eaad99 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -426,6 +426,13 @@ struct HandlerInner {
 
     future_breakage_diagnostics: Vec<Diagnostic>,
 
+    /// The [`Self::unstable_expect_diagnostics`] should be empty when this struct is
+    /// dropped. However, it can have values if the compilation is stopped early
+    /// or is only partially executed. To avoid ICEs, like in rust#94953 we only
+    /// check if [`Self::unstable_expect_diagnostics`] is empty, if the expectation ids
+    /// have been converted.
+    check_unstable_expect_diagnostics: bool,
+
     /// Expected [`Diagnostic`]s store a [`LintExpectationId`] as part of
     /// the lint level. [`LintExpectationId`]s created early during the compilation
     /// (before `HirId`s have been defined) are not stable and can therefore not be
@@ -497,10 +504,12 @@ impl Drop for HandlerInner {
             );
         }
 
-        assert!(
-            self.unstable_expect_diagnostics.is_empty(),
-            "all diagnostics with unstable expectations should have been converted",
-        );
+        if self.check_unstable_expect_diagnostics {
+            assert!(
+                self.unstable_expect_diagnostics.is_empty(),
+                "all diagnostics with unstable expectations should have been converted",
+            );
+        }
     }
 }
 
@@ -574,6 +583,7 @@ impl Handler {
                 emitted_diagnostics: Default::default(),
                 stashed_diagnostics: Default::default(),
                 future_breakage_diagnostics: Vec::new(),
+                check_unstable_expect_diagnostics: false,
                 unstable_expect_diagnostics: Vec::new(),
                 fulfilled_expectations: Default::default(),
             }),
@@ -988,12 +998,13 @@ impl Handler {
         &self,
         unstable_to_stable: &FxHashMap<LintExpectationId, LintExpectationId>,
     ) {
-        let diags = std::mem::take(&mut self.inner.borrow_mut().unstable_expect_diagnostics);
+        let mut inner = self.inner.borrow_mut();
+        let diags = std::mem::take(&mut inner.unstable_expect_diagnostics);
+        inner.check_unstable_expect_diagnostics = true;
         if diags.is_empty() {
             return;
         }
 
-        let mut inner = self.inner.borrow_mut();
         for mut diag in diags.into_iter() {
             diag.update_unstable_expectation_id(unstable_to_stable);