Auto merge of #94096 - cjgillot:ensure-stability, r=lcnr

Ensure stability directives are checked in all cases

Split off  #93017

Stability and deprecation were not checked in all cases, for instance if a type error happened.
This PR moves the check earlier in the pipeline to ensure the errors are emitted in all cases.

r? `@lcnr`

7 files changed, 72 insertions, 99 deletions

diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 6c44fb0df23..570ec45557d 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -420,6 +420,31 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 }
             }
         }
+
+        // Emit errors for non-staged-api crates.
+        if !self.features.staged_api {
+            if attr.has_name(sym::rustc_deprecated)
+                || attr.has_name(sym::unstable)
+                || attr.has_name(sym::stable)
+                || attr.has_name(sym::rustc_const_unstable)
+                || attr.has_name(sym::rustc_const_stable)
+            {
+                struct_span_err!(
+                    self.sess,
+                    attr.span,
+                    E0734,
+                    "stability attributes may not be used outside of the standard library",
+                )
+                .emit();
+            }
+        } else {
+            if attr.has_name(sym::deprecated) {
+                self.sess
+                    .struct_span_err(attr.span, "`#[deprecated]` cannot be used in staged API")
+                    .span_label(attr.span, "use `#[rustc_deprecated]` instead")
+                    .emit();
+            }
+        }
     }
 
     fn visit_item(&mut self, i: &'a ast::Item) {
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index d43c6fec7d5..762198887cf 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -167,6 +167,7 @@ fn get_features(
             if let Some(Feature { since, .. }) = ACCEPTED_FEATURES.iter().find(|f| name == f.name) {
                 let since = Some(Symbol::intern(since));
                 features.declared_lang_features.push((name, mi.span(), since));
+                features.active_features.insert(name);
                 continue;
             }
 
@@ -187,10 +188,12 @@ fn get_features(
             if let Some(f) = ACTIVE_FEATURES.iter().find(|f| name == f.name) {
                 f.set(&mut features, mi.span());
                 features.declared_lang_features.push((name, mi.span(), None));
+                features.active_features.insert(name);
                 continue;
             }
 
             features.declared_lib_features.push((name, mi.span()));
+            features.active_features.insert(name);
         }
     }
 
diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index 1d9d16e85cb..1f7dc769512 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -2,6 +2,7 @@
 
 use super::{to_nonzero, Feature, State};
 
+use rustc_data_structures::fx::FxHashSet;
 use rustc_span::edition::Edition;
 use rustc_span::symbol::{sym, Symbol};
 use rustc_span::Span;
@@ -47,6 +48,8 @@ macro_rules! declare_features {
             pub declared_lang_features: Vec<(Symbol, Span, Option<Symbol>)>,
             /// `#![feature]` attrs for non-language (library) features.
             pub declared_lib_features: Vec<(Symbol, Span)>,
+            /// Features enabled for this crate.
+            pub active_features: FxHashSet<Symbol>,
             $(
                 $(#[doc = $doc])*
                 pub $feature: bool
@@ -58,6 +61,11 @@ macro_rules! declare_features {
                 $(f(stringify!($feature), self.$feature);)+
             }
 
+            /// Is the given feature active?
+            pub fn active(&self, feature: Symbol) -> bool {
+                self.active_features.contains(&feature)
+            }
+
             /// Is the given feature enabled?
             ///
             /// Panics if the symbol doesn't correspond to a declared feature.
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 35688a65912..1aceb4e95e6 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -922,11 +922,17 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
                 });
             },
             {
+                sess.time("unused_lib_feature_checking", || {
+                    rustc_passes::stability::check_unused_or_stable_features(tcx)
+                });
+            },
+            {
                 // We force these querie to run,
                 // since they might not otherwise get called.
                 // This marks the corresponding crate-level attributes
                 // as used, and ensures that their values are valid.
                 tcx.ensure().limits(());
+                tcx.ensure().stability_index(());
             }
         );
     });
@@ -999,11 +1005,6 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
                             .par_for_each_module(|module| tcx.ensure().check_mod_deathness(module));
                     },
                     {
-                        sess.time("unused_lib_feature_checking", || {
-                            rustc_passes::stability::check_unused_or_stable_features(tcx)
-                        });
-                    },
-                    {
                         sess.time("lint_checking", || {
                             rustc_lint::check_crate(tcx, || {
                                 rustc_lint::BuiltinCombinedLateLintPass::new()
diff --git a/compiler/rustc_middle/src/middle/stability.rs b/compiler/rustc_middle/src/middle/stability.rs
index ff19c33d8e8..167a097d9f8 100644
--- a/compiler/rustc_middle/src/middle/stability.rs
+++ b/compiler/rustc_middle/src/middle/stability.rs
@@ -6,12 +6,12 @@ pub use self::StabilityLevel::*;
 use crate::ty::{self, DefIdTree, TyCtxt};
 use rustc_ast::NodeId;
 use rustc_attr::{self as attr, ConstStability, Deprecation, Stability};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_feature::GateIssue;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX};
+use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX};
 use rustc_hir::{self, HirId};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_session::lint::builtin::{DEPRECATED, DEPRECATED_IN_FUTURE, SOFT_UNSTABLE};
@@ -63,12 +63,6 @@ pub struct Index {
     pub stab_map: FxHashMap<LocalDefId, Stability>,
     pub const_stab_map: FxHashMap<LocalDefId, ConstStability>,
     pub depr_map: FxHashMap<LocalDefId, DeprecationEntry>,
-
-    /// Maps for each crate whether it is part of the staged API.
-    pub staged_api: FxHashMap<CrateNum, bool>,
-
-    /// Features enabled for this crate.
-    pub active_features: FxHashSet<Symbol>,
 }
 
 impl Index {
@@ -423,7 +417,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     debug!("stability: skipping span={:?} since it is internal", span);
                     return EvalResult::Allow;
                 }
-                if self.stability().active_features.contains(&feature) {
+                if self.features().active(feature) {
                     return EvalResult::Allow;
                 }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 8ce1b9d4425..36d93de9a33 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -2999,11 +2999,6 @@ pub fn provide(providers: &mut ty::query::Providers) {
         tcx.arena.alloc(tcx.resolutions(()).glob_map.get(&id).cloned().unwrap_or_default())
     };
 
-    providers.lookup_stability = |tcx, id| tcx.stability().local_stability(id.expect_local());
-    providers.lookup_const_stability =
-        |tcx, id| tcx.stability().local_const_stability(id.expect_local());
-    providers.lookup_deprecation_entry =
-        |tcx, id| tcx.stability().local_deprecation_entry(id.expect_local());
     providers.extern_mod_stmt_cnum =
         |tcx, id| tcx.resolutions(()).extern_crate_map.get(&id).cloned();
     providers.output_filenames = |tcx, ()| &tcx.output_filenames;
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index df3853d8744..37a9f0ecd8c 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -1,13 +1,12 @@
 //! A pass that annotates every item and method with its stability level,
 //! propagating default levels lexically from parent to children ast nodes.
 
-use rustc_ast::Attribute;
 use rustc_attr::{self as attr, ConstStability, Stability};
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, CRATE_DEF_INDEX};
 use rustc_hir::hir_id::CRATE_HIR_ID;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{FieldDef, Generics, HirId, Item, TraitRef, Ty, TyKind, Variant};
@@ -113,12 +112,8 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
     {
         let attrs = self.tcx.get_attrs(def_id.to_def_id());
         debug!("annotate(id = {:?}, attrs = {:?})", def_id, attrs);
-        let mut did_error = false;
-        if !self.tcx.features().staged_api {
-            did_error = self.forbid_staged_api_attrs(def_id, attrs, inherit_deprecation.clone());
-        }
 
-        let depr = if did_error { None } else { attr::find_deprecation(&self.tcx.sess, attrs) };
+        let depr = attr::find_deprecation(&self.tcx.sess, attrs);
         let mut is_deprecated = false;
         if let Some((depr, span)) = &depr {
             is_deprecated = true;
@@ -148,16 +143,15 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             }
         }
 
-        if self.tcx.features().staged_api {
-            if let Some(a) = attrs.iter().find(|a| a.has_name(sym::deprecated)) {
-                self.tcx
-                    .sess
-                    .struct_span_err(a.span, "`#[deprecated]` cannot be used in staged API")
-                    .span_label(a.span, "use `#[rustc_deprecated]` instead")
-                    .span_label(item_sp, "")
-                    .emit();
+        if !self.tcx.features().staged_api {
+            // Propagate unstability.  This can happen even for non-staged-api crates in case
+            // -Zforce-unstable-if-unmarked is set.
+            if let Some(stab) = self.parent_stab {
+                if inherit_deprecation.yes() && stab.level.is_unstable() {
+                    self.index.stab_map.insert(def_id, stab);
+                }
             }
-        } else {
+
             self.recurse_with_stability_attrs(
                 depr.map(|(d, _)| DeprecationEntry::local(d, def_id)),
                 None,
@@ -329,47 +323,6 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             self.parent_const_stab = orig_parent_const_stab;
         }
     }
-
-    // returns true if an error occurred, used to suppress some spurious errors
-    fn forbid_staged_api_attrs(
-        &mut self,
-        def_id: LocalDefId,
-        attrs: &[Attribute],
-        inherit_deprecation: InheritDeprecation,
-    ) -> bool {
-        // Emit errors for non-staged-api crates.
-        let unstable_attrs = [
-            sym::unstable,
-            sym::stable,
-            sym::rustc_deprecated,
-            sym::rustc_const_unstable,
-            sym::rustc_const_stable,
-        ];
-        let mut has_error = false;
-        for attr in attrs {
-            let name = attr.name_or_empty();
-            if unstable_attrs.contains(&name) {
-                struct_span_err!(
-                    self.tcx.sess,
-                    attr.span,
-                    E0734,
-                    "stability attributes may not be used outside of the standard library",
-                )
-                .emit();
-                has_error = true;
-            }
-        }
-
-        // Propagate unstability.  This can happen even for non-staged-api crates in case
-        // -Zforce-unstable-if-unmarked is set.
-        if let Some(stab) = self.parent_stab {
-            if inherit_deprecation.yes() && stab.level.is_unstable() {
-                self.index.stab_map.insert(def_id, stab);
-            }
-        }
-
-        has_error
-    }
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
@@ -654,28 +607,12 @@ impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> {
 }
 
 fn stability_index(tcx: TyCtxt<'_>, (): ()) -> Index {
-    let is_staged_api =
-        tcx.sess.opts.debugging_opts.force_unstable_if_unmarked || tcx.features().staged_api;
-    let mut staged_api = FxHashMap::default();
-    staged_api.insert(LOCAL_CRATE, is_staged_api);
     let mut index = Index {
-        staged_api,
         stab_map: Default::default(),
         const_stab_map: Default::default(),
         depr_map: Default::default(),
-        active_features: Default::default(),
     };
 
-    let active_lib_features = &tcx.features().declared_lib_features;
-    let active_lang_features = &tcx.features().declared_lang_features;
-
-    // Put the active features into a map for quick lookup.
-    index.active_features = active_lib_features
-        .iter()
-        .map(|&(s, ..)| s)
-        .chain(active_lang_features.iter().map(|&(s, ..)| s))
-        .collect();
-
     {
         let mut annotator = Annotator {
             tcx,
@@ -728,7 +665,16 @@ fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
 }
 
 pub(crate) fn provide(providers: &mut Providers) {
-    *providers = Providers { check_mod_unstable_api_usage, stability_index, ..*providers };
+    *providers = Providers {
+        check_mod_unstable_api_usage,
+        stability_index,
+        lookup_stability: |tcx, id| tcx.stability().local_stability(id.expect_local()),
+        lookup_const_stability: |tcx, id| tcx.stability().local_const_stability(id.expect_local()),
+        lookup_deprecation_entry: |tcx, id| {
+            tcx.stability().local_deprecation_entry(id.expect_local())
+        },
+        ..*providers
+    };
 }
 
 struct Checker<'tcx> {
@@ -884,9 +830,10 @@ impl<'tcx> Visitor<'tcx> for CheckTraitImplStable<'tcx> {
 /// were expected to be library features), and the list of features used from
 /// libraries, identify activated features that don't exist and error about them.
 pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
-    let access_levels = &tcx.privacy_access_levels(());
-
-    if tcx.stability().staged_api[&LOCAL_CRATE] {
+    let is_staged_api =
+        tcx.sess.opts.debugging_opts.force_unstable_if_unmarked || tcx.features().staged_api;
+    if is_staged_api {
+        let access_levels = &tcx.privacy_access_levels(());
         let mut missing = MissingStabilityAnnotations { tcx, access_levels };
         missing.check_missing_stability(CRATE_DEF_ID, tcx.hir().span(CRATE_HIR_ID));
         tcx.hir().walk_toplevel_module(&mut missing);
@@ -907,7 +854,7 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     }
 
     let declared_lib_features = &tcx.features().declared_lib_features;
-    let mut remaining_lib_features = FxHashMap::default();
+    let mut remaining_lib_features = FxIndexMap::default();
     for (feature, span) in declared_lib_features {
         if !tcx.sess.opts.unstable_features.is_nightly_build() {
             struct_span_err!(
@@ -934,7 +881,7 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
     remaining_lib_features.remove(&sym::libc);
     remaining_lib_features.remove(&sym::test);
 
-    let check_features = |remaining_lib_features: &mut FxHashMap<_, _>, defined_features: &[_]| {
+    let check_features = |remaining_lib_features: &mut FxIndexMap<_, _>, defined_features: &[_]| {
         for &(feature, since) in defined_features {
             if let Some(since) = since {
                 if let Some(span) = remaining_lib_features.get(&feature) {