Rollup merge of rust-lang#156596 - nnethercote:split-LintExpectation, r=GuillaumeGomez

Split `LintExpectationId`s

This PR makes clearer where stable and unstable `LintExpectationIds` can occur, plus a few other small cleanups. Details in individual commits.

r? @GuillaumeGomez

Author: JonathanBrouwer

compiler/rustc_codegen_ssa/src/lib.rs

@@ -27,7 +27,7 @@ use rustc_lint_defs::builtin::LINKER_INFO;
 use rustc_macros::{Decodable, Encodable};
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::WorkProduct;
-use rustc_middle::lint::LevelSpec;
+use rustc_middle::lint::StableLevelSpec;
 use rustc_middle::middle::debugger_visualizer::DebuggerVisualizerFile;
 use rustc_middle::middle::dependency_format::Dependencies;
 use rustc_middle::middle::exported_symbols::SymbolExportKind;
@@ -374,8 +374,8 @@ impl CompiledModules {
 /// Instead, encode exactly the information we need.
 #[derive(Copy, Clone, Debug, Encodable, Decodable)]
 pub struct CodegenLintLevelSpecs {
-    linker_messages: LevelSpec,
-    linker_info: LevelSpec,
+    linker_messages: StableLevelSpec,
+    linker_info: StableLevelSpec,
 }
 
 impl CodegenLintLevelSpecs {

compiler/rustc_lint/src/context.rs

@@ -20,14 +20,17 @@ use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use rustc_hir::{Pat, PatKind};
 use rustc_middle::bug;
-use rustc_middle::lint::LevelSpec;
+use rustc_middle::lint::{LevelSpec, StableLevelSpec, UnstableLevelSpec};
 use rustc_middle::middle::privacy::EffectiveVisibilities;
 use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::print::{PrintError, PrintTraitRefExt as _, Printer, with_no_trimmed_paths};
 use rustc_middle::ty::{
     self, GenericArg, RegisteredTools, Ty, TyCtxt, TypingEnv, TypingMode, Unnormalized,
 };
-use rustc_session::lint::{FutureIncompatibleInfo, Lint, LintExpectationId, LintId};
+use rustc_session::lint::{
+    FutureIncompatibleInfo, Lint, LintExpectationId, LintId, StableLintExpectationId,
+    UnstableLintExpectationId,
+};
 use rustc_session::{DynLintStore, Session};
 use rustc_span::edit_distance::find_best_match_for_names;
 use rustc_span::{Ident, Span, Symbol, sym};
@@ -510,6 +513,8 @@ pub struct EarlyContext<'a> {
 }
 
 pub trait LintContext {
+    type LintExpectationId: Copy + Into<LintExpectationId>;
+
     fn sess(&self) -> &Session;
 
     // FIXME: These methods should not take an Into<MultiSpan> -- instead, callers should need to
@@ -538,7 +543,7 @@ pub trait LintContext {
     }
 
     /// This returns the lint level spec for the given lint at the current location.
-    fn get_lint_level_spec(&self, lint: &'static Lint) -> LevelSpec;
+    fn get_lint_level_spec(&self, lint: &'static Lint) -> LevelSpec<Self::LintExpectationId>;
 
     /// This function can be used to manually fulfill an expectation. This can
     /// be used for lints which contain several spans, and should be suppressed,
@@ -547,7 +552,7 @@ pub trait LintContext {
     /// Note that this function should only be called for [`LintExpectationId`]s
     /// retrieved from the current lint pass. Buffered or manually created ids can
     /// cause ICEs.
-    fn fulfill_expectation(&self, expectation: LintExpectationId) {
+    fn fulfill_expectation(&self, expectation: Self::LintExpectationId) {
         // We need to make sure that submitted expectation ids are correctly fulfilled suppressed
         // and stored between compilation sessions. To not manually do these steps, we simply create
         // a dummy diagnostic and emit it as usual, which will be suppressed and stored like a
@@ -556,7 +561,7 @@ pub trait LintContext {
             .dcx()
             .struct_expect(
                 "this is a dummy diagnostic, to submit and store an expectation",
-                expectation,
+                expectation.into(),
             )
             .emit();
     }
@@ -585,6 +590,8 @@ impl<'a> EarlyContext<'a> {
 }
 
 impl<'tcx> LintContext for LateContext<'tcx> {
+    type LintExpectationId = StableLintExpectationId;
+
     /// Gets the overall compiler `Session` object.
     fn sess(&self) -> &Session {
         self.tcx.sess
@@ -604,12 +611,14 @@ impl<'tcx> LintContext for LateContext<'tcx> {
         }
     }
 
-    fn get_lint_level_spec(&self, lint: &'static Lint) -> LevelSpec {
+    fn get_lint_level_spec(&self, lint: &'static Lint) -> StableLevelSpec {
         self.tcx.lint_level_spec_at_node(lint, self.last_node_with_lint_attrs)
     }
 }
 
 impl LintContext for EarlyContext<'_> {
+    type LintExpectationId = UnstableLintExpectationId;
+
     /// Gets the overall compiler `Session` object.
     fn sess(&self) -> &Session {
         self.builder.sess()
@@ -624,7 +633,7 @@ impl LintContext for EarlyContext<'_> {
         self.builder.opt_span_lint(lint, span.map(|s| s.into()), decorator)
     }
 
-    fn get_lint_level_spec(&self, lint: &'static Lint) -> LevelSpec {
+    fn get_lint_level_spec(&self, lint: &'static Lint) -> UnstableLevelSpec {
         self.builder.lint_level_spec(lint)
     }
 }

compiler/rustc_lint/src/early.rs

@@ -53,7 +53,7 @@ impl<'ecx, T: EarlyLintPass> EarlyContextAndPass<'ecx, T> {
     {
         let is_crate_node = id == ast::CRATE_NODE_ID;
         debug!(?id);
-        let push = self.context.builder.push(attrs, is_crate_node, None);
+        let push = self.context.builder.push(attrs, is_crate_node);
 
         debug!("early context: enter_attrs({:?})", attrs);
         lint_callback!(self, check_attributes, attrs);

compiler/rustc_lint/src/expect.rs

@@ -2,8 +2,8 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_middle::lint::LintExpectation;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::lint::LintExpectationId;
 use rustc_session::lint::builtin::UNFULFILLED_LINT_EXPECTATIONS;
+use rustc_session::lint::{LintExpectationId, StableLintExpectationId};
 use rustc_span::Symbol;
 
 use crate::lints::{Expectation, ExpectationNote};
@@ -12,7 +12,7 @@ pub(crate) fn provide(providers: &mut Providers) {
     *providers = Providers { lint_expectations, check_expectations, ..*providers };
 }
 
-fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(LintExpectationId, LintExpectation)> {
+fn lint_expectations(tcx: TyCtxt<'_>, (): ()) -> Vec<(StableLintExpectationId, LintExpectation)> {
     let krate = tcx.hir_crate_items(());
 
     let mut expectations = Vec::new();
@@ -31,30 +31,22 @@ fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
 
     // Turn a `LintExpectationId` into a `(AttrId, lint_index)` pair.
     let canonicalize_id = |expect_id: &LintExpectationId| {
-        match *expect_id {
-            LintExpectationId::Unstable { attr_id, lint_index: Some(lint_index) } => {
-                (attr_id, lint_index)
-            }
-            LintExpectationId::Stable { hir_id, attr_index, lint_index: Some(lint_index) } => {
+        let (attr_id, lint_index) = match *expect_id {
+            LintExpectationId::Unstable(id) => (id.attr_id, id.lint_index),
+            LintExpectationId::Stable(id) => {
                 // We are an `eval_always` query, so looking at the attribute's `AttrId` is ok.
-                let attr_id = tcx.hir_attrs(hir_id)[attr_index as usize].id();
-
-                (attr_id, lint_index)
+                (tcx.hir_attrs(id.hir_id)[id.attr_index as usize].id(), id.lint_index)
             }
-            _ => panic!("fulfilled expectations must have a lint index"),
-        }
+        };
+        (attr_id, lint_index.expect("fulfilled expectations must have a lint index"))
     };
 
     let fulfilled_expectations: FxHashSet<_> =
         fulfilled_expectations.iter().map(canonicalize_id).collect();
 
     for (expect_id, expectation) in lint_expectations {
-        // This check will always be true, since `lint_expectations` only holds stable ids
-        let LintExpectationId::Stable { hir_id, .. } = expect_id else {
-            unreachable!("at this stage all `LintExpectationId`s are stable");
-        };
-
-        let expect_id = canonicalize_id(expect_id);
+        let hir_id = expect_id.hir_id;
+        let expect_id = canonicalize_id(&LintExpectationId::Stable(*expect_id));
 
         if !fulfilled_expectations.contains(&expect_id)
             && tool_filter.is_none_or(|filter| expectation.lint_tool == Some(filter))
@@ -63,7 +55,7 @@ fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
             let note = expectation.is_unfulfilled_lint_expectations;
             tcx.emit_node_span_lint(
                 UNFULFILLED_LINT_EXPECTATIONS,
-                *hir_id,
+                hir_id,
                 expectation.emission_span,
                 Expectation { rationale, note },
             );

compiler/rustc_lint/src/late.rs

@@ -439,14 +439,6 @@ fn late_lint_crate<'tcx>(tcx: TyCtxt<'tcx>) {
 
     filtered_passes.push(Box::new(HardwiredLints));
     let pass = RuntimeCombinedLateLintPass { passes: &mut filtered_passes[..] };
-    late_lint_crate_inner(tcx, context, pass);
-}
-
-fn late_lint_crate_inner<'tcx, T: LateLintPass<'tcx>>(
-    tcx: TyCtxt<'tcx>,
-    context: LateContext<'tcx>,
-    pass: T,
-) {
     let mut cx = LateContextAndPass { context, pass };
 
     // Visit the whole crate.