Move four fields from ParseSess to Session.

`ParseSess` is separate from, but sits within, `Session`. The separation
is because there are some places (e.g. `Parser` methods) where
`ParseSess` is available but `Session` is not.

However, `ParseSess` has four fields that are only accessed from places
where `Session` is also available. This commit moves those fields to
`Session`. This means that `ParseSess` only contains the fields it
genuinely needs, and various `sess.psess.foo` occurrences are reduced to
`sess.foo`.

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -222,7 +222,7 @@ pub(crate) fn parse_name_value<S: Stage>(
         }
     };
 
-    match cx.sess.psess.check_config.expecteds.get(&name) {
+    match cx.sess.check_config.expecteds.get(&name) {
         Some(ExpectedValues::Some(values)) if !values.contains(&value.map(|(v, _)| v)) => cx
             .emit_lint_with_sess(
                 UNEXPECTED_CFGS,
@@ -232,7 +232,7 @@ pub(crate) fn parse_name_value<S: Stage>(
                 },
                 span,
             ),
-        None if cx.sess.psess.check_config.exhaustive_names => cx.emit_lint_with_sess(
+        None if cx.sess.check_config.exhaustive_names => cx.emit_lint_with_sess(
             UNEXPECTED_CFGS,
             move |dcx, level, sess| {
                 check_cfg::unexpected_cfg_name(sess, (name, name_span), value).into_diag(dcx, level)
@@ -280,7 +280,7 @@ pub fn eval_config_entry(sess: &Session, cfg_entry: &CfgEntry) -> EvalConfigResu
             }
         }
         CfgEntry::NameValue { name, value, span } => {
-            if sess.psess.config.contains(&(*name, *value)) {
+            if sess.config.contains(&(*name, *value)) {
                 EvalConfigResult::True
             } else {
                 EvalConfigResult::False { reason: cfg_entry.clone(), reason_span: *span }

compiler/rustc_attr_parsing/src/attributes/diagnostic/check_cfg.rs

@@ -25,9 +25,8 @@ fn sort_and_truncate_possibilities(
     } else {
         match filter_well_known_names {
             FilterWellKnownNames::Yes => {
-                possibilities.retain(|cfg_name| {
-                    !sess.psess.check_config.well_known_names.contains(cfg_name)
-                });
+                possibilities
+                    .retain(|cfg_name| !sess.check_config.well_known_names.contains(cfg_name));
             }
             FilterWellKnownNames::No => {}
         };
@@ -105,13 +104,12 @@ pub(crate) fn unexpected_cfg_name(
     value: Option<(Symbol, Span)>,
 ) -> errors::UnexpectedCfgName {
     #[allow(rustc::potential_query_instability)]
-    let possibilities: Vec<Symbol> = sess.psess.check_config.expecteds.keys().copied().collect();
+    let possibilities: Vec<Symbol> = sess.check_config.expecteds.keys().copied().collect();
 
     let mut names_possibilities: Vec<_> = if value.is_none() {
         // We later sort and display all the possibilities, so the order here does not matter.
         #[allow(rustc::potential_query_instability)]
-        sess.psess
-            .check_config
+        sess.check_config
             .expecteds
             .iter()
             .filter_map(|(k, v)| match v {
@@ -167,7 +165,7 @@ pub(crate) fn unexpected_cfg_name(
         is_feature_cfg |= best_match == sym::feature;
 
         if let Some(ExpectedValues::Some(best_match_values)) =
-            sess.psess.check_config.expecteds.get(&best_match)
+            sess.check_config.expecteds.get(&best_match)
         {
             // We will soon sort, so the initial order does not matter.
             #[allow(rustc::potential_query_instability)]
@@ -285,7 +283,7 @@ pub(crate) fn unexpected_cfg_value(
     (name, name_span): (Symbol, Span),
     value: Option<(Symbol, Span)>,
 ) -> errors::UnexpectedCfgValue {
-    let Some(ExpectedValues::Some(values)) = &sess.psess.check_config.expecteds.get(&name) else {
+    let Some(ExpectedValues::Some(values)) = &sess.check_config.expecteds.get(&name) else {
         panic!(
             "it shouldn't be possible to have a diagnostic on a value whose name is not in values"
         );
@@ -305,7 +303,7 @@ pub(crate) fn unexpected_cfg_value(
     let is_from_external_macro = name_span.in_external_macro(sess.source_map());
 
     let code_sugg = if let Some((value, _)) = value
-        && sess.psess.check_config.well_known_names.contains(&name)
+        && sess.check_config.well_known_names.contains(&name)
         && let valid_names = possible_well_known_names_for_cfg_value(sess, value)
         && !valid_names.is_empty()
     {
@@ -378,12 +376,12 @@ pub(crate) fn unexpected_cfg_value(
     // We don't want to encourage people to add values to a well-known names, as these are
     // defined by rustc/Rust itself. Users can still do this if they wish, but should not be
     // encouraged to do so.
-    let can_suggest_adding_value = !sess.psess.check_config.well_known_names.contains(&name)
+    let can_suggest_adding_value = !sess.check_config.well_known_names.contains(&name)
         // Except when working on rustc or the standard library itself, in which case we want to
         // suggest adding these cfgs to the "normal" place because of bootstrapping reasons. As a
         // basic heuristic, we use the "cheat" unstable feature enable method and the
         // non-ui-testing enabled option.
-        || (matches!(sess.psess.unstable_features, rustc_feature::UnstableFeatures::Cheat)
+        || (matches!(sess.unstable_features, rustc_feature::UnstableFeatures::Cheat)
             && !sess.opts.unstable_opts.ui_testing);
 
     let inst = |escape_quotes| {
@@ -429,13 +427,11 @@ pub(crate) fn unexpected_cfg_value(
 fn possible_well_known_names_for_cfg_value(sess: &Session, value: Symbol) -> Vec<Symbol> {
     #[allow(rustc::potential_query_instability)]
     let mut names = sess
-        .psess
         .check_config
         .well_known_names
         .iter()
         .filter(|name| {
-            sess.psess
-                .check_config
+            sess.check_config
                 .expecteds
                 .get(*name)
                 .map(|expected_values| expected_values.contains(&Some(value)))

compiler/rustc_codegen_ssa/src/assert_module_sources.rs

@@ -171,7 +171,7 @@ impl<'tcx> AssertModuleSource<'tcx> {
     /// Scan for a `cfg="foo"` attribute and check whether we have a
     /// cfg flag called `foo`.
     fn check_config(&self, value: Symbol) -> bool {
-        let config = &self.tcx.sess.psess.config;
+        let config = &self.tcx.sess.config;
         debug!("check_config(config={:?}, value={:?})", config, value);
         if config.iter().any(|&(name, _)| name == value) {
             debug!("check_config: matched");

compiler/rustc_driver_impl/src/lib.rs

@@ -734,7 +734,6 @@ fn print_crate_info(
             }
             Cfg => {
                 let mut cfgs = sess
-                    .psess
                     .config
                     .iter()
                     .filter_map(|&(name, value)| {
@@ -763,7 +762,7 @@ fn print_crate_info(
 
                 // INSTABILITY: We are sorting the output below.
                 #[allow(rustc::potential_query_instability)]
-                for (name, expected_values) in &sess.psess.check_config.expecteds {
+                for (name, expected_values) in &sess.check_config.expecteds {
                     use crate::config::ExpectedValues;
                     match expected_values {
                         ExpectedValues::Any => {
@@ -791,9 +790,7 @@ fn print_crate_info(
                 }
 
                 check_cfgs.sort_unstable();
-                if !sess.psess.check_config.exhaustive_names
-                    && sess.psess.check_config.exhaustive_values
-                {
+                if !sess.check_config.exhaustive_names && sess.check_config.exhaustive_values {
                     println_info!("cfg(any())");
                 }
                 for check_cfg in check_cfgs {

compiler/rustc_expand/src/proc_macro_server.rs

@@ -15,6 +15,7 @@ use rustc_proc_macro::bridge::{
     DelimSpan, Diagnostic, ExpnGlobals, Group, Ident, LitKind, Literal, Punct, TokenTree, server,
 };
 use rustc_proc_macro::{Delimiter, Level};
+use rustc_session::Session;
 use rustc_session::parse::ParseSess;
 use rustc_span::def_id::CrateNum;
 use rustc_span::{BytePos, FileName, Pos, Span, Symbol, sym};
@@ -440,6 +441,10 @@ impl<'a, 'b> Rustc<'a, 'b> {
         }
     }
 
+    fn sess(&self) -> &Session {
+        &self.ecx.sess
+    }
+
     fn psess(&self) -> &ParseSess {
         self.ecx.psess()
     }
@@ -825,7 +830,7 @@ impl server::Server for Rustc<'_, '_> {
     /// since we've loaded `my_proc_macro` from disk in order to execute it).
     /// In this way, we have obtained a span pointing into `my_proc_macro`
     fn span_save_span(&mut self, span: Self::Span) -> usize {
-        self.psess().save_proc_macro_span(span)
+        self.sess().save_proc_macro_span(span)
     }
 
     fn span_recover_proc_macro_span(&mut self, id: usize) -> Self::Span {

compiler/rustc_incremental/src/persist/clean.rs

@@ -183,12 +183,7 @@ impl<'tcx> CleanVisitor<'tcx> {
         item_id: LocalDefId,
         attr: &RustcCleanAttribute,
     ) -> Option<Assertion> {
-        self.tcx
-            .sess
-            .psess
-            .config
-            .contains(&(attr.cfg, None))
-            .then(|| self.assertion_auto(item_id, attr))
+        self.tcx.sess.config.contains(&(attr.cfg, None)).then(|| self.assertion_auto(item_id, attr))
     }
 
     /// Gets the "auto" assertion on pre-validated attr, along with the `except` labels.
@@ -406,7 +401,7 @@ struct FindAllAttrs<'tcx> {
 
 impl<'tcx> FindAllAttrs<'tcx> {
     fn is_active_attr(&self, attr: &RustcCleanAttribute) -> bool {
-        self.tcx.sess.psess.config.contains(&(attr.cfg, None))
+        self.tcx.sess.config.contains(&(attr.cfg, None))
     }
 
     fn report_unchecked_attrs(&self, mut checked_attrs: FxHashSet<Span>) {

compiler/rustc_interface/src/interface.rs

@@ -452,11 +452,11 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
             let cfg = parse_cfg(sess.dcx(), config.crate_cfg);
             let mut cfg = config::build_configuration(&sess, cfg);
             util::add_configuration(&mut cfg, &mut sess, &*codegen_backend);
-            sess.psess.config = cfg;
+            sess.config = cfg;
 
             let mut check_cfg = parse_check_cfg(sess.dcx(), config.crate_check_cfg);
             check_cfg.fill_well_known(&sess.target);
-            sess.psess.check_config = check_cfg;
+            sess.check_config = check_cfg;
 
             if let Some(psess_created) = config.psess_created {
                 psess_created(&mut sess.psess);

compiler/rustc_metadata/src/dependency_format.rs

@@ -309,7 +309,7 @@ fn add_library(
             // This error is probably a little obscure, but I imagine that it
             // can be refined over time.
             if link2 != link || link == RequireStatic {
-                let linking_to_rustc_driver = tcx.sess.psess.unstable_features.is_nightly_build()
+                let linking_to_rustc_driver = tcx.sess.unstable_features.is_nightly_build()
                     && tcx.crates(()).iter().any(|&cnum| tcx.crate_name(cnum) == sym::rustc_driver);
                 tcx.dcx().emit_err(CrateDepMultiple {
                     crate_name: tcx.crate_name(cnum),

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1984,7 +1984,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             let stability = tcx.lookup_stability(CRATE_DEF_ID);
             let macros =
                 self.lazy_array(tcx.resolutions(()).proc_macros.iter().map(|p| p.local_def_index));
-            for (i, span) in self.tcx.sess.psess.proc_macro_quoted_spans() {
+            for (i, span) in self.tcx.sess.proc_macro_quoted_spans() {
                 let span = self.lazy(span);
                 self.tables.proc_macro_quoted_spans.set_some(i, span);
             }

compiler/rustc_session/src/parse.rs

@@ -14,14 +14,13 @@ use rustc_errors::{
     BufferedEarlyLint, ColorConfig, DecorateDiagCompat, Diag, DiagCtxt, DiagCtxtHandle,
     DiagMessage, EmissionGuarantee, Level, MultiSpan, StashKey,
 };
-use rustc_feature::{GateIssue, UnstableFeatures, find_feature_issue};
+use rustc_feature::{GateIssue, find_feature_issue};
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::ExpnId;
 use rustc_span::source_map::{FilePathMapping, SourceMap};
 use rustc_span::{Span, Symbol, sym};
 
 use crate::Session;
-use crate::config::{Cfg, CheckCfg};
 use crate::errors::{
     CliFeatureDiagnosticHelp, FeatureDiagnosticForIssue, FeatureDiagnosticHelp,
     FeatureDiagnosticSuggestion, FeatureGateError, SuggestUpgradeCompiler,
@@ -182,7 +181,7 @@ pub fn add_feature_diagnostics_for_issue<G: EmissionGuarantee>(
     }
 
     // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
-    if sess.psess.unstable_features.is_nightly_build() {
+    if sess.unstable_features.is_nightly_build() {
         if feature_from_cli {
             err.subdiagnostic(CliFeatureDiagnosticHelp { feature });
         } else if let Some(span) = inject_span {
@@ -226,7 +225,7 @@ pub fn feature_err_unstable_feature_bound(
     let mut err = sess.dcx().create_err(FeatureGateError { span, explain: explain.into() });
 
     // #23973: do not suggest `#![feature(...)]` if we are in beta/stable
-    if sess.psess.unstable_features.is_nightly_build() {
+    if sess.unstable_features.is_nightly_build() {
         err.subdiagnostic(FeatureDiagnosticHelp { feature });
 
         if feature == sym::rustc_attrs {
@@ -245,9 +244,6 @@ pub fn feature_err_unstable_feature_bound(
 /// Info about a parsing session.
 pub struct ParseSess {
     dcx: DiagCtxt,
-    pub unstable_features: UnstableFeatures,
-    pub config: Cfg,
-    pub check_config: CheckCfg,
     pub edition: Edition,
     /// Places where raw identifiers were used. This is used to avoid complaining about idents
     /// clashing with keywords in new editions.
@@ -264,9 +260,6 @@ pub struct ParseSess {
     pub ambiguous_block_expr_parse: Lock<FxIndexMap<Span, Span>>,
     pub gated_spans: GatedSpans,
     pub symbol_gallery: SymbolGallery,
-    /// Spans passed to `proc_macro::quote_span`. Each span has a numerical
-    /// identifier represented by its position in the vector.
-    proc_macro_quoted_spans: AppendOnlyVec<Span>,
     /// Used to generate new `AttrId`s. Every `AttrId` is unique.
     pub attr_id_generator: AttrIdGenerator,
 }
@@ -286,9 +279,6 @@ impl ParseSess {
     pub fn with_dcx(dcx: DiagCtxt, source_map: Arc<SourceMap>) -> Self {
         Self {
             dcx,
-            unstable_features: UnstableFeatures::from_environment(None),
-            config: Cfg::default(),
-            check_config: CheckCfg::default(),
             edition: ExpnId::root().expn_data().edition,
             raw_identifier_spans: Default::default(),
             bad_unicode_identifiers: Lock::new(Default::default()),
@@ -297,7 +287,6 @@ impl ParseSess {
             ambiguous_block_expr_parse: Lock::new(Default::default()),
             gated_spans: GatedSpans::default(),
             symbol_gallery: SymbolGallery::default(),
-            proc_macro_quoted_spans: Default::default(),
             attr_id_generator: AttrIdGenerator::new(),
         }
     }
@@ -385,16 +374,6 @@ impl ParseSess {
         });
     }
 
-    pub fn save_proc_macro_span(&self, span: Span) -> usize {
-        self.proc_macro_quoted_spans.push(span)
-    }
-
-    pub fn proc_macro_quoted_spans(&self) -> impl Iterator<Item = (usize, Span)> {
-        // This is equivalent to `.iter().copied().enumerate()`, but that isn't possible for
-        // AppendOnlyVec, so we resort to this scheme.
-        self.proc_macro_quoted_spans.iter_enumerated()
-    }
-
     pub fn dcx(&self) -> DiagCtxtHandle<'_> {
         self.dcx.handle()
     }

compiler/rustc_session/src/session.rs

@@ -10,7 +10,9 @@ use rustc_data_structures::base_n::{CASE_INSENSITIVE, ToBaseN};
 use rustc_data_structures::flock;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_data_structures::profiling::{SelfProfiler, SelfProfilerRef};
-use rustc_data_structures::sync::{DynSend, DynSync, Lock, MappedReadGuard, ReadGuard, RwLock};
+use rustc_data_structures::sync::{
+    AppendOnlyVec, DynSend, DynSync, Lock, MappedReadGuard, ReadGuard, RwLock,
+};
 use rustc_errors::annotate_snippet_emitter_writer::AnnotateSnippetEmitter;
 use rustc_errors::codes::*;
 use rustc_errors::emitter::{DynEmitter, HumanReadableErrorType, OutputTheme, stderr_destination};
@@ -20,6 +22,7 @@ use rustc_errors::{
     Diag, DiagCtxt, DiagCtxtHandle, DiagMessage, Diagnostic, ErrorGuaranteed, FatalAbort,
     TerminalUrl,
 };
+use rustc_feature::UnstableFeatures;
 use rustc_hir::limit::Limit;
 use rustc_macros::HashStable_Generic;
 pub use rustc_span::def_id::StableCrateId;
@@ -36,8 +39,9 @@ use rustc_target::spec::{
 use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, FieldKind, SizeKind, VariantInfo};
 use crate::config::{
-    self, CoverageLevel, CoverageOptions, CrateType, DebugInfo, ErrorOutputType, FunctionReturn,
-    Input, InstrumentCoverage, OptLevel, OutFileName, OutputType, SwitchWithOptPath,
+    self, Cfg, CheckCfg, CoverageLevel, CoverageOptions, CrateType, DebugInfo, ErrorOutputType,
+    FunctionReturn, Input, InstrumentCoverage, OptLevel, OutFileName, OutputType,
+    SwitchWithOptPath,
 };
 use crate::filesearch::FileSearch;
 use crate::lint::LintId;
@@ -91,6 +95,13 @@ pub struct Session {
     pub opts: config::Options,
     pub target_tlib_path: Arc<SearchPath>,
     pub psess: ParseSess,
+    pub unstable_features: UnstableFeatures,
+    pub config: Cfg,
+    pub check_config: CheckCfg,
+    /// Spans passed to `proc_macro::quote_span`. Each span has a numerical
+    /// identifier represented by its position in the vector.
+    proc_macro_quoted_spans: AppendOnlyVec<Span>,
+
     /// Input, input file path and output file path to this compilation process.
     pub io: CompilerIO,
 
@@ -302,6 +313,16 @@ impl Session {
         self.psess.source_map()
     }
 
+    pub fn proc_macro_quoted_spans(&self) -> impl Iterator<Item = (usize, Span)> {
+        // This is equivalent to `.iter().copied().enumerate()`, but that isn't possible for
+        // AppendOnlyVec, so we resort to this scheme.
+        self.proc_macro_quoted_spans.iter_enumerated()
+    }
+
+    pub fn save_proc_macro_span(&self, span: Span) -> usize {
+        self.proc_macro_quoted_spans.push(span)
+    }
+
     /// Returns `true` if internal lints should be added to the lint store - i.e. if
     /// `-Zunstable-options` is provided and this isn't rustdoc (internal lints can trigger errors
     /// to be emitted under rustdoc).
@@ -1089,6 +1110,10 @@ pub fn build_session(
         opts: sopts,
         target_tlib_path,
         psess,
+        unstable_features: UnstableFeatures::from_environment(None),
+        config: Cfg::default(),
+        check_config: CheckCfg::default(),
+        proc_macro_quoted_spans: Default::default(),
         io,
         incr_comp_session: RwLock::new(IncrCompSession::NotInitialized),
         prof,