rustc: Move features from Session to GlobalCtxt

Removes two pieces of mutable state.
Follow up to rust-lang#114622.

Cargo.lock

@@ -3805,6 +3805,7 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_expand",
+ "rustc_feature",
  "rustc_fluent_macro",
  "rustc_fs_util",
  "rustc_hir",

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -13,6 +13,7 @@ use rustc_ast::*;
 use rustc_ast::{walk_list, StaticItem};
 use rustc_ast_pretty::pprust::{self, State};
 use rustc_data_structures::fx::FxIndexMap;
+use rustc_feature::Features;
 use rustc_macros::Subdiagnostic;
 use rustc_parse::validate_attr;
 use rustc_session::lint::builtin::{
@@ -45,6 +46,7 @@ enum DisallowTildeConstContext<'a> {
 
 struct AstValidator<'a> {
     session: &'a Session,
+    features: &'a Features,
 
     /// The span of the `extern` in an `extern { ... }` block, if any.
     extern_mod: Option<&'a Item>,
@@ -1023,7 +1025,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 }
                 self.check_type_no_bounds(bounds, "this context");
 
-                if self.session.features_untracked().lazy_type_alias {
+                if self.features.lazy_type_alias {
                     if let Err(err) = self.check_type_alias_where_clause_location(ty_alias) {
                         self.err_handler().emit_err(err);
                     }
@@ -1500,9 +1502,15 @@ fn deny_equality_constraints(
     this.err_handler().emit_err(err);
 }
 
-pub fn check_crate(session: &Session, krate: &Crate, lints: &mut LintBuffer) -> bool {
+pub fn check_crate(
+    session: &Session,
+    features: &Features,
+    krate: &Crate,
+    lints: &mut LintBuffer,
+) -> bool {
     let mut validator = AstValidator {
         session,
+        features,
         extern_mod: None,
         in_trait_impl: false,
         in_const_trait_impl: false,

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -514,10 +514,10 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     }
 }
 
-pub fn check_crate(krate: &ast::Crate, sess: &Session) {
-    maybe_stage_features(sess, krate);
-    check_incompatible_features(sess);
-    let mut visitor = PostExpansionVisitor { sess, features: &sess.features_untracked() };
+pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
+    maybe_stage_features(sess, features, krate);
+    check_incompatible_features(sess, features);
+    let mut visitor = PostExpansionVisitor { sess, features };
 
     let spans = sess.parse_sess.gated_spans.spans.borrow();
     macro_rules! gate_all {
@@ -600,12 +600,12 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
     visit::walk_crate(&mut visitor, krate);
 }
 
-fn maybe_stage_features(sess: &Session, krate: &ast::Crate) {
+fn maybe_stage_features(sess: &Session, features: &Features, krate: &ast::Crate) {
     // checks if `#![feature]` has been used to enable any lang feature
     // does not check the same for lib features unless there's at least one
     // declared lang feature
     if !sess.opts.unstable_features.is_nightly_build() {
-        let lang_features = &sess.features_untracked().declared_lang_features;
+        let lang_features = &features.declared_lang_features;
         if lang_features.len() == 0 {
             return;
         }
@@ -640,9 +640,7 @@ fn maybe_stage_features(sess: &Session, krate: &ast::Crate) {
     }
 }
 
-fn check_incompatible_features(sess: &Session) {
-    let features = sess.features_untracked();
-
+fn check_incompatible_features(sess: &Session, features: &Features) {
     let declared_features = features
         .declared_lang_features
         .iter()

compiler/rustc_attr/src/builtin.rs

@@ -800,18 +800,15 @@ pub struct Deprecation {
 }
 
 /// Finds the deprecation attribute. `None` if none exists.
-pub fn find_deprecation(sess: &Session, attrs: &[Attribute]) -> Option<(Deprecation, Span)> {
-    find_deprecation_generic(sess, attrs.iter())
-}
-
-fn find_deprecation_generic<'a, I>(sess: &Session, attrs_iter: I) -> Option<(Deprecation, Span)>
-where
-    I: Iterator<Item = &'a Attribute>,
-{
+pub fn find_deprecation(
+    sess: &Session,
+    features: &Features,
+    attrs: &[Attribute],
+) -> Option<(Deprecation, Span)> {
     let mut depr: Option<(Deprecation, Span)> = None;
-    let is_rustc = sess.features_untracked().staged_api;
+    let is_rustc = features.staged_api;
 
-    'outer: for attr in attrs_iter {
+    'outer: for attr in attrs {
         if !attr.has_name(sym::deprecated) {
             continue;
         }
@@ -872,7 +869,7 @@ where
                                 }
                             }
                             sym::suggestion => {
-                                if !sess.features_untracked().deprecated_suggestion {
+                                if !features.deprecated_suggestion {
                                     sess.emit_err(session_diagnostics::DeprecatedItemSuggestion {
                                         span: mi.span,
                                         is_nightly: sess.is_nightly_build().then_some(()),
@@ -890,7 +887,7 @@ where
                                     meta.span(),
                                     AttrError::UnknownMetaItem(
                                         pprust::path_to_string(&mi.path),
-                                        if sess.features_untracked().deprecated_suggestion {
+                                        if features.deprecated_suggestion {
                                             &["since", "note", "suggestion"]
                                         } else {
                                             &["since", "note"]

compiler/rustc_builtin_macros/src/assert.rs

@@ -69,7 +69,7 @@ pub fn expand_assert<'cx>(
     // If `generic_assert` is enabled, generates rich captured outputs
     //
     // FIXME(c410-f3r) See https://github.com/rust-lang/rust/issues/96949
-    else if let Some(features) = cx.ecfg.features && features.generic_assert {
+    else if cx.ecfg.features.generic_assert {
         context::Context::new(cx, call_site_span).build(cond_expr, panic_path())
     }
     // If `generic_assert` is not enabled, only outputs a literal "assertion failed: ..."

compiler/rustc_builtin_macros/src/cfg.rs

@@ -24,7 +24,7 @@ pub fn expand_cfg(
                 &cfg,
                 &cx.sess.parse_sess,
                 cx.current_expansion.lint_node_id,
-                cx.ecfg.features,
+                Some(cx.ecfg.features),
             );
             MacEager::expr(cx.expr_bool(sp, matches_cfg))
         }

compiler/rustc_builtin_macros/src/cfg_eval.rs

@@ -31,10 +31,11 @@ pub(crate) fn expand(
 
 pub(crate) fn cfg_eval(
     sess: &Session,
-    features: Option<&Features>,
+    features: &Features,
     annotatable: Annotatable,
     lint_node_id: NodeId,
 ) -> Annotatable {
+    let features = Some(features);
     CfgEval { cfg: &mut StripUnconfigured { sess, features, config_tokens: true, lint_node_id } }
         .configure_annotatable(annotatable)
         // Since the item itself has already been configured by the `InvocationCollector`,

compiler/rustc_builtin_macros/src/proc_macro_harness.rs

@@ -5,6 +5,7 @@ use rustc_ast::{self as ast, attr, NodeId};
 use rustc_ast_pretty::pprust;
 use rustc_expand::base::{parse_macro_name_and_helper_attrs, ExtCtxt, ResolverExpand};
 use rustc_expand::expand::{AstFragment, ExpansionConfig};
+use rustc_feature::Features;
 use rustc_session::Session;
 use rustc_span::hygiene::AstPass;
 use rustc_span::source_map::SourceMap;
@@ -46,13 +47,14 @@ struct CollectProcMacros<'a> {
 pub fn inject(
     krate: &mut ast::Crate,
     sess: &Session,
+    features: &Features,
     resolver: &mut dyn ResolverExpand,
     is_proc_macro_crate: bool,
     has_proc_macro_decls: bool,
     is_test_crate: bool,
     handler: &rustc_errors::Handler,
 ) {
-    let ecfg = ExpansionConfig::default("proc_macro".to_string());
+    let ecfg = ExpansionConfig::default("proc_macro".to_string(), features);
     let mut cx = ExtCtxt::new(sess, ecfg, resolver, None);
 
     let mut collect = CollectProcMacros {

compiler/rustc_builtin_macros/src/standard_library_imports.rs

@@ -1,6 +1,7 @@
 use rustc_ast::{self as ast, attr};
 use rustc_expand::base::{ExtCtxt, ResolverExpand};
 use rustc_expand::expand::ExpansionConfig;
+use rustc_feature::Features;
 use rustc_session::Session;
 use rustc_span::edition::Edition::*;
 use rustc_span::hygiene::AstPass;
@@ -13,6 +14,7 @@ pub fn inject(
     pre_configured_attrs: &[ast::Attribute],
     resolver: &mut dyn ResolverExpand,
     sess: &Session,
+    features: &Features,
 ) -> usize {
     let orig_num_items = krate.items.len();
     let edition = sess.parse_sess.edition;
@@ -39,7 +41,7 @@ pub fn inject(
     let span = DUMMY_SP.with_def_site_ctxt(expn_id.to_expn_id());
     let call_site = DUMMY_SP.with_call_site_ctxt(expn_id.to_expn_id());
 
-    let ecfg = ExpansionConfig::default("std_lib_injection".to_string());
+    let ecfg = ExpansionConfig::default("std_lib_injection".to_string(), features);
     let cx = ExtCtxt::new(sess, ecfg, resolver, None);
 
     // .rev() to preserve ordering above in combination with insert(0, ...)

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -41,7 +41,12 @@ struct TestCtxt<'a> {
 
 /// Traverse the crate, collecting all the test functions, eliding any
 /// existing main functions, and synthesizing a main test harness
-pub fn inject(krate: &mut ast::Crate, sess: &Session, resolver: &mut dyn ResolverExpand) {
+pub fn inject(
+    krate: &mut ast::Crate,
+    sess: &Session,
+    features: &Features,
+    resolver: &mut dyn ResolverExpand,
+) {
     let span_diagnostic = sess.diagnostic();
     let panic_strategy = sess.panic_strategy();
     let platform_panic_strategy = sess.target.panic_strategy;
@@ -76,7 +81,7 @@ pub fn inject(krate: &mut ast::Crate, sess: &Session, resolver: &mut dyn Resolve
             resolver,
             reexport_test_harness_main,
             krate,
-            &sess.features_untracked(),
+            features,
             panic_strategy,
             test_runner,
         )
@@ -243,9 +248,7 @@ fn generate_test_harness(
     panic_strategy: PanicStrategy,
     test_runner: Option<ast::Path>,
 ) {
-    let mut econfig = ExpansionConfig::default("test".to_string());
-    econfig.features = Some(features);
-
+    let econfig = ExpansionConfig::default("test".to_string(), features);
     let ext_cx = ExtCtxt::new(sess, econfig, resolver, None);
 
     let expn_id = ext_cx.resolver.expansion_for_ast_pass(

compiler/rustc_expand/src/base.rs

@@ -18,6 +18,7 @@ use rustc_errors::{
     Applicability, DiagnosticBuilder, DiagnosticMessage, ErrorGuaranteed, IntoDiagnostic,
     MultiSpan, PResult,
 };
+use rustc_feature::Features;
 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
 use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics, RegisteredTools};
 use rustc_parse::{self, parser, MACRO_ARGUMENTS};
@@ -767,6 +768,7 @@ impl SyntaxExtension {
     /// and other properties converted from attributes.
     pub fn new(
         sess: &Session,
+        features: &Features,
         kind: SyntaxExtensionKind,
         span: Span,
         helper_attrs: Vec<Symbol>,
@@ -816,7 +818,7 @@ impl SyntaxExtension {
             allow_internal_unstable: (!allow_internal_unstable.is_empty())
                 .then(|| allow_internal_unstable.into()),
             stability: stability.map(|(s, _)| s),
-            deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
+            deprecation: attr::find_deprecation(&sess, features, attrs).map(|(d, _)| d),
             helper_attrs,
             edition,
             builtin_name,
@@ -957,6 +959,7 @@ pub trait LintStoreExpand {
     fn pre_expansion_lint(
         &self,
         sess: &Session,
+        features: &Features,
         registered_tools: &RegisteredTools,
         node_id: NodeId,
         attrs: &[Attribute],

compiler/rustc_expand/src/expand.rs

@@ -796,7 +796,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             | Annotatable::FieldDef(..)
             | Annotatable::Variant(..) => panic!("unexpected annotatable"),
         };
-        if self.cx.ecfg.proc_macro_hygiene() {
+        if self.cx.ecfg.features.proc_macro_hygiene {
             return;
         }
         feature_err(
@@ -834,7 +834,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             }
         }
 
-        if !self.cx.ecfg.proc_macro_hygiene() {
+        if !self.cx.ecfg.features.proc_macro_hygiene {
             annotatable
                 .visit_with(&mut GateProcMacroInput { parse_sess: &self.cx.sess.parse_sess });
         }
@@ -1122,6 +1122,7 @@ impl InvocationCollectorNode for P<ast::Item> {
                 if let Some(lint_store) = ecx.lint_store {
                     lint_store.pre_expansion_lint(
                         ecx.sess,
+                        ecx.ecfg.features,
                         ecx.resolver.registered_tools(),
                         ecx.current_expansion.lint_node_id,
                         &attrs,
@@ -1580,7 +1581,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     fn cfg(&self) -> StripUnconfigured<'_> {
         StripUnconfigured {
             sess: &self.cx.sess,
-            features: self.cx.ecfg.features,
+            features: Some(self.cx.ecfg.features),
             config_tokens: false,
             lint_node_id: self.cx.current_expansion.lint_node_id,
         }
@@ -1676,7 +1677,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     // Detect use of feature-gated or invalid attributes on macro invocations
     // since they will not be detected after macro expansion.
     fn check_attributes(&self, attrs: &[ast::Attribute], call: &ast::MacCall) {
-        let features = self.cx.ecfg.features.unwrap();
+        let features = self.cx.ecfg.features;
         let mut attrs = attrs.iter().peekable();
         let mut span: Option<Span> = None;
         while let Some(attr) = attrs.next() {
@@ -1976,7 +1977,7 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
 
 pub struct ExpansionConfig<'feat> {
     pub crate_name: String,
-    pub features: Option<&'feat Features>,
+    pub features: &'feat Features,
     pub recursion_limit: Limit,
     pub trace_mac: bool,
     /// If false, strip `#[test]` nodes
@@ -1987,20 +1988,16 @@ pub struct ExpansionConfig<'feat> {
     pub proc_macro_backtrace: bool,
 }
 
-impl<'feat> ExpansionConfig<'feat> {
-    pub fn default(crate_name: String) -> ExpansionConfig<'static> {
+impl ExpansionConfig<'_> {
+    pub fn default(crate_name: String, features: &Features) -> ExpansionConfig<'_> {
         ExpansionConfig {
             crate_name,
-            features: None,
+            features,
             recursion_limit: Limit::new(1024),
             trace_mac: false,
             should_test: false,
             span_debug: false,
             proc_macro_backtrace: false,
         }
     }
-
-    fn proc_macro_hygiene(&self) -> bool {
-        self.features.is_some_and(|features| features.proc_macro_hygiene)
-    }
 }