Rollup of 18 pull requests

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -338,15 +338,11 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_expr(&mut self, e: &'a ast::Expr) {
         match e.kind {
             ast::ExprKind::TryBlock(_, None) => {
+                // `try { ... }` is old and is only gated post-expansion here.
                 gate!(&self, try_blocks, e.span, "`try` expression is experimental");
             }
             ast::ExprKind::TryBlock(_, Some(_)) => {
-                gate!(
-                    &self,
-                    try_blocks_heterogeneous,
-                    e.span,
-                    "`try bikeshed` expression is experimental"
-                );
+                // `try_blocks_heterogeneous` is new, and gated pre-expansion instead.
             }
             ast::ExprKind::Lit(token::Lit {
                 kind: token::LitKind::Float | token::LitKind::Integer,
@@ -522,6 +518,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         half_open_range_patterns_in_slices,
         "half-open range patterns in slices are unstable"
     );
+    gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
     gate_all!(yeet_expr, "`do yeet` expression is experimental");
     gate_all!(const_closures, "const closures are experimental");
     gate_all!(builtin_syntax, "`builtin #` syntax is unstable");

compiler/rustc_attr_parsing/src/attributes/rustc_internal.rs

@@ -1211,3 +1211,12 @@ impl<S: Stage> SingleAttributeParser<S> for RustcReservationImplParser {
         Some(AttributeKind::RustcReservationImpl(cx.attr_span, value_str))
     }
 }
+
+pub(crate) struct PreludeImportParser;
+
+impl<S: Stage> NoArgsAttributeParser<S> for PreludeImportParser {
+    const PATH: &[Symbol] = &[sym::prelude_import];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Use)]);
+    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::PreludeImport;
+}

compiler/rustc_attr_parsing/src/context.rs

@@ -258,6 +258,7 @@ attribute_parsers!(
         Single<WithoutArgs<PassByValueParser>>,
         Single<WithoutArgs<PinV2Parser>>,
         Single<WithoutArgs<PointeeParser>>,
+        Single<WithoutArgs<PreludeImportParser>>,
         Single<WithoutArgs<ProcMacroAttributeParser>>,
         Single<WithoutArgs<ProcMacroParser>>,
         Single<WithoutArgs<ProfilerRuntimeParser>>,

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -649,8 +649,8 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
         // We want to focus on relevant live locals in diagnostics, so when polonius is enabled, we
         // ensure that we don't emit live boring locals as explanations.
         let is_local_boring = |local| {
-            if let Some(polonius_diagnostics) = self.polonius_diagnostics {
-                polonius_diagnostics.boring_nll_locals.contains(&local)
+            if let Some(polonius_context) = self.polonius_context {
+                polonius_context.boring_nll_locals.contains(&local)
             } else {
                 assert!(!tcx.sess.opts.unstable_opts.polonius.is_next_enabled());
 

compiler/rustc_borrowck/src/lib.rs

@@ -63,10 +63,10 @@ use crate::diagnostics::{
 use crate::path_utils::*;
 use crate::place_ext::PlaceExt;
 use crate::places_conflict::{PlaceConflictBias, places_conflict};
+use crate::polonius::PoloniusContext;
 use crate::polonius::legacy::{
     PoloniusFacts, PoloniusFactsExt, PoloniusLocationTable, PoloniusOutput,
 };
-use crate::polonius::{PoloniusContext, PoloniusDiagnosticsContext};
 use crate::prefixes::PrefixSet;
 use crate::region_infer::RegionInferenceContext;
 use crate::region_infer::opaque_types::DeferredOpaqueTypeError;
@@ -424,7 +424,7 @@ fn borrowck_check_region_constraints<'tcx>(
         polonius_output,
         opt_closure_req,
         nll_errors,
-        polonius_diagnostics,
+        polonius_context,
     } = nll::compute_regions(
         root_cx,
         &infcx,
@@ -448,7 +448,7 @@ fn borrowck_check_region_constraints<'tcx>(
         &regioncx,
         &opt_closure_req,
         &borrow_set,
-        polonius_diagnostics.as_ref(),
+        polonius_context.as_ref(),
     );
 
     // We also have a `#[rustc_regions]` annotation that causes us to dump
@@ -490,7 +490,7 @@ fn borrowck_check_region_constraints<'tcx>(
             polonius_output: None,
             move_errors: Vec::new(),
             diags_buffer,
-            polonius_diagnostics: polonius_diagnostics.as_ref(),
+            polonius_context: polonius_context.as_ref(),
         };
         struct MoveVisitor<'a, 'b, 'infcx, 'tcx> {
             ctxt: &'a mut MirBorrowckCtxt<'b, 'infcx, 'tcx>,
@@ -529,7 +529,7 @@ fn borrowck_check_region_constraints<'tcx>(
         move_errors: Vec::new(),
         diags_buffer,
         polonius_output: polonius_output.as_deref(),
-        polonius_diagnostics: polonius_diagnostics.as_ref(),
+        polonius_context: polonius_context.as_ref(),
     };
 
     // Compute and report region errors, if any.
@@ -779,7 +779,7 @@ struct MirBorrowckCtxt<'a, 'infcx, 'tcx> {
     /// Results of Polonius analysis.
     polonius_output: Option<&'a PoloniusOutput>,
     /// When using `-Zpolonius=next`: the data used to compute errors and diagnostics.
-    polonius_diagnostics: Option<&'a PoloniusDiagnosticsContext>,
+    polonius_context: Option<&'a PoloniusContext>,
 }
 
 // Check that:

compiler/rustc_borrowck/src/nll.rs

@@ -23,10 +23,10 @@ use crate::borrow_set::BorrowSet;
 use crate::consumers::RustcFacts;
 use crate::diagnostics::RegionErrors;
 use crate::handle_placeholders::compute_sccs_applying_placeholder_outlives_constraints;
+use crate::polonius::PoloniusContext;
 use crate::polonius::legacy::{
     PoloniusFacts, PoloniusFactsExt, PoloniusLocationTable, PoloniusOutput,
 };
-use crate::polonius::{PoloniusContext, PoloniusDiagnosticsContext};
 use crate::region_infer::RegionInferenceContext;
 use crate::type_check::MirTypeckRegionConstraints;
 use crate::type_check::free_region_relations::UniversalRegionRelations;
@@ -47,7 +47,7 @@ pub(crate) struct NllOutput<'tcx> {
 
     /// When using `-Zpolonius=next`: the data used to compute errors and diagnostics, e.g.
     /// localized typeck and liveness constraints.
-    pub polonius_diagnostics: Option<PoloniusDiagnosticsContext>,
+    pub polonius_context: Option<PoloniusContext>,
 }
 
 /// Rewrites the regions in the MIR to use NLL variables, also scraping out the set of universal
@@ -122,7 +122,7 @@ pub(crate) fn compute_regions<'tcx>(
     universal_region_relations: Frozen<UniversalRegionRelations<'tcx>>,
     constraints: MirTypeckRegionConstraints<'tcx>,
     mut polonius_facts: Option<AllFacts<RustcFacts>>,
-    polonius_context: Option<PoloniusContext>,
+    mut polonius_context: Option<PoloniusContext>,
 ) -> NllOutput<'tcx> {
     let polonius_output = root_cx.consumer.as_ref().map_or(false, |c| c.polonius_output())
         || infcx.tcx.sess.opts.unstable_opts.polonius.is_legacy_enabled();
@@ -154,9 +154,9 @@ pub(crate) fn compute_regions<'tcx>(
 
     // If requested for `-Zpolonius=next`, convert NLL constraints to localized outlives constraints
     // and use them to compute loan liveness.
-    let polonius_diagnostics = polonius_context.map(|polonius_context| {
-        polonius_context.compute_loan_liveness(infcx.tcx, &mut regioncx, body, borrow_set)
-    });
+    if let Some(polonius_context) = polonius_context.as_mut() {
+        polonius_context.compute_loan_liveness(&mut regioncx, body, borrow_set)
+    }
 
     // If requested: dump NLL facts, and run legacy polonius analysis.
     let polonius_output = polonius_facts.as_ref().and_then(|polonius_facts| {
@@ -189,7 +189,7 @@ pub(crate) fn compute_regions<'tcx>(
         polonius_output,
         opt_closure_req: closure_region_requirements,
         nll_errors,
-        polonius_diagnostics,
+        polonius_context,
     }
 }