Rollup of 8 pull requests

compiler/rustc_ast/src/ast.rs

@@ -1441,7 +1441,7 @@ pub enum ExprKind {
     /// `'label: loop { block }`
     Loop(P<Block>, Option<Label>, Span),
     /// A `match` block.
-    Match(P<Expr>, ThinVec<Arm>),
+    Match(P<Expr>, ThinVec<Arm>, MatchKind),
     /// A closure (e.g., `move |a, b, c| a + b + c`).
     Closure(Box<Closure>),
     /// A block (`'label: { ... }`).
@@ -1766,6 +1766,15 @@ pub enum StrStyle {
     Raw(u8),
 }
 
+/// The kind of match expression
+#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq)]
+pub enum MatchKind {
+    /// match expr { ... }
+    Prefix,
+    /// expr.match { ... }
+    Postfix,
+}
+
 /// A literal in a meta item.
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct MetaItemLit {

compiler/rustc_ast/src/mut_visit.rs

@@ -1425,7 +1425,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             visit_opt(label, |label| vis.visit_label(label));
             vis.visit_span(span);
         }
-        ExprKind::Match(expr, arms) => {
+        ExprKind::Match(expr, arms, _kind) => {
             vis.visit_expr(expr);
             arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
         }

compiler/rustc_ast/src/visit.rs

@@ -923,7 +923,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) -> V
             visit_opt!(visitor, visit_label, opt_label);
             try_visit!(visitor.visit_block(block));
         }
-        ExprKind::Match(subexpression, arms) => {
+        ExprKind::Match(subexpression, arms, _kind) => {
             try_visit!(visitor.visit_expr(subexpression));
             walk_list!(visitor, visit_arm, arms);
         }

compiler/rustc_ast_lowering/src/expr.rs

@@ -181,10 +181,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     )
                 }),
                 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
-                ExprKind::Match(expr, arms) => hir::ExprKind::Match(
+                ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
                     self.lower_expr(expr),
                     self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
-                    hir::MatchSource::Normal,
+                    match kind {
+                        MatchKind::Prefix => hir::MatchSource::Normal,
+                        MatchKind::Postfix => hir::MatchSource::Postfix,
+                    },
                 ),
                 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
                 ExprKind::Closure(box Closure {

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -564,6 +564,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(generic_const_items, "generic const items are experimental");
     gate_all!(unnamed_fields, "unnamed fields are not yet fully implemented");
     gate_all!(fn_delegation, "functions delegation is not yet fully implemented");
+    gate_all!(postfix_match, "postfix match is experimental");
 
     if !visitor.features.never_patterns {
         if let Some(spans) = spans.get(&sym::never_patterns) {

compiler/rustc_ast_pretty/src/pprust/state/expr.rs

@@ -1,6 +1,6 @@
 use crate::pp::Breaks::Inconsistent;
 use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
-use ast::ForLoopKind;
+use ast::{ForLoopKind, MatchKind};
 use itertools::{Itertools, Position};
 use rustc_ast::ptr::P;
 use rustc_ast::token;
@@ -589,12 +589,22 @@ impl<'a> State<'a> {
                 self.word_nbsp("loop");
                 self.print_block_with_attrs(blk, attrs);
             }
-            ast::ExprKind::Match(expr, arms) => {
+            ast::ExprKind::Match(expr, arms, match_kind) => {
                 self.cbox(0);
                 self.ibox(0);
-                self.word_nbsp("match");
-                self.print_expr_as_cond(expr);
-                self.space();
+
+                match match_kind {
+                    MatchKind::Prefix => {
+                        self.word_nbsp("match");
+                        self.print_expr_as_cond(expr);
+                        self.space();
+                    }
+                    MatchKind::Postfix => {
+                        self.print_expr_as_cond(expr);
+                        self.word_nbsp(".match");
+                    }
+                }
+
                 self.bopen();
                 self.print_inner_attributes_no_trailing_hardbreak(attrs);
                 for arm in arms {

compiler/rustc_borrowck/src/type_check/canonical.rs

@@ -82,7 +82,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     ) {
         self.prove_predicate(
             ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::Trait(
-                ty::TraitPredicate { trait_ref, polarity: ty::ImplPolarity::Positive },
+                ty::TraitPredicate { trait_ref, polarity: ty::PredicatePolarity::Positive },
             ))),
             locations,
             category,

compiler/rustc_builtin_macros/src/assert/context.rs

@@ -245,7 +245,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
             ExprKind::Let(_, local_expr, _, _) => {
                 self.manage_cond_expr(local_expr);
             }
-            ExprKind::Match(local_expr, _) => {
+            ExprKind::Match(local_expr, ..) => {
                 self.manage_cond_expr(local_expr);
             }
             ExprKind::MethodCall(call) => {

compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs

@@ -132,7 +132,7 @@ fn cs_partial_cmp(
                 // Reference: https://github.com/rust-lang/rust/pull/103659#issuecomment-1328126354
 
                 if !tag_then_data
-                    && let ExprKind::Match(_, arms) = &mut expr1.kind
+                    && let ExprKind::Match(_, arms, _) = &mut expr1.kind
                     && let Some(last) = arms.last_mut()
                     && let PatKind::Wild = last.pat.kind
                 {

compiler/rustc_builtin_macros/src/deriving/debug.rs

@@ -2,8 +2,7 @@ use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
 
-use ast::EnumDef;
-use rustc_ast::{self as ast, MetaItem};
+use rustc_ast::{self as ast, EnumDef, MetaItem};
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::Span;

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -85,14 +85,6 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
 
         let bx = self;
 
-        match coverage.kind {
-            // Marker statements have no effect during codegen,
-            // so return early and don't create `func_coverage`.
-            CoverageKind::SpanMarker | CoverageKind::BlockMarker { .. } => return,
-            // Match exhaustively to ensure that newly-added kinds are classified correctly.
-            CoverageKind::CounterIncrement { .. } | CoverageKind::ExpressionUsed { .. } => {}
-        }
-
         let Some(function_coverage_info) =
             bx.tcx.instance_mir(instance.def).function_coverage_info.as_deref()
         else {
@@ -109,7 +101,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
         let Coverage { kind } = coverage;
         match *kind {
             CoverageKind::SpanMarker | CoverageKind::BlockMarker { .. } => unreachable!(
-                "unexpected marker statement {kind:?} should have caused an early return"
+                "marker statement {kind:?} should have been removed by CleanupPostBorrowck"
             ),
             CoverageKind::CounterIncrement { id } => {
                 func_coverage.mark_counter_id_seen(id);

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -1159,11 +1159,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         };
 
         // Side-step AllocRef and directly access the underlying bytes more efficiently.
-        // (We are staying inside the bounds here so all is good.)
+        // (We are staying inside the bounds here and all bytes do get overwritten so all is good.)
         let alloc_id = alloc_ref.alloc_id;
         let bytes = alloc_ref
             .alloc
-            .get_bytes_mut(&alloc_ref.tcx, alloc_ref.range)
+            .get_bytes_unchecked_for_overwrite(&alloc_ref.tcx, alloc_ref.range)
             .map_err(move |e| e.to_interp_error(alloc_id))?;
         // `zip` would stop when the first iterator ends; we want to definitely
         // cover all of `bytes`.
@@ -1184,6 +1184,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.mem_copy_repeatedly(src, dest, size, 1, nonoverlapping)
     }
 
+    /// Performs `num_copies` many copies of `size` many bytes from `src` to `dest + i*size` (where
+    /// `i` is the index of the copy).
+    ///
+    /// Either `nonoverlapping` must be true or `num_copies` must be 1; doing repeated copies that
+    /// may overlap is not supported.
     pub fn mem_copy_repeatedly(
         &mut self,
         src: Pointer<Option<M::Provenance>>,
@@ -1245,8 +1250,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             (dest_alloc_id, dest_prov),
             dest_range,
         )?;
+        // Yes we do overwrite all bytes in `dest_bytes`.
         let dest_bytes = dest_alloc
-            .get_bytes_mut_ptr(&tcx, dest_range)
+            .get_bytes_unchecked_for_overwrite_ptr(&tcx, dest_range)
             .map_err(|e| e.to_interp_error(dest_alloc_id))?
             .as_mut_ptr();
 
@@ -1280,6 +1286,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     }
                 }
             }
+            if num_copies > 1 {
+                assert!(nonoverlapping, "multi-copy only supported in non-overlapping mode");
+            }
 
             let size_in_bytes = size.bytes_usize();
             // For particularly large arrays (where this is perf-sensitive) it's common that
@@ -1292,6 +1301,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             } else if src_alloc_id == dest_alloc_id {
                 let mut dest_ptr = dest_bytes;
                 for _ in 0..num_copies {
+                    // Here we rely on `src` and `dest` being non-overlapping if there is more than
+                    // one copy.
                     ptr::copy(src_bytes, dest_ptr, size_in_bytes);
                     dest_ptr = dest_ptr.add(size_in_bytes);
                 }

compiler/rustc_const_eval/src/transform/validate.rs

@@ -4,6 +4,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
 use rustc_infer::traits::Reveal;
+use rustc_middle::mir::coverage::CoverageKind;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
@@ -345,11 +346,21 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
                     self.fail(location, format!("explicit `{kind:?}` is forbidden"));
                 }
             }
+            StatementKind::Coverage(coverage) => {
+                let kind = &coverage.kind;
+                if self.mir_phase >= MirPhase::Analysis(AnalysisPhase::PostCleanup)
+                    && let CoverageKind::BlockMarker { .. } | CoverageKind::SpanMarker { .. } = kind
+                {
+                    self.fail(
+                        location,
+                        format!("{kind:?} should have been removed after analysis"),
+                    );
+                }
+            }
             StatementKind::Assign(..)
             | StatementKind::StorageLive(_)
             | StatementKind::StorageDead(_)
             | StatementKind::Intrinsic(_)
-            | StatementKind::Coverage(_)
             | StatementKind::ConstEvalCounter
             | StatementKind::PlaceMention(..)
             | StatementKind::Nop => {}

compiler/rustc_driver_impl/src/signal_handler.rs

@@ -1,6 +1,7 @@
 //! Signal handler for rustc
 //! Primarily used to extract a backtrace from stack overflow
 
+use rustc_interface::util::{DEFAULT_STACK_SIZE, STACK_SIZE};
 use std::alloc::{alloc, Layout};
 use std::{fmt, mem, ptr};
 
@@ -100,7 +101,10 @@ extern "C" fn print_stack_trace(_: libc::c_int) {
         written += 1;
     }
     raw_errln!("note: we would appreciate a report at https://github.com/rust-lang/rust");
-    written += 1;
+    // get the current stack size WITHOUT blocking and double it
+    let new_size = STACK_SIZE.get().copied().unwrap_or(DEFAULT_STACK_SIZE) * 2;
+    raw_errln!("help: you can increase rustc's stack size by setting RUST_MIN_STACK={new_size}");
+    written += 2;
     if written > 24 {
         // We probably just scrolled the earlier "we got SIGSEGV" message off the terminal
         raw_errln!("note: backtrace dumped due to SIGSEGV! resuming signal");

compiler/rustc_expand/src/build.rs

@@ -1,6 +1,6 @@
 use crate::base::ExtCtxt;
 use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, PatKind, UnOp};
+use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, MatchKind, PatKind, UnOp};
 use rustc_ast::{attr, token, util::literal};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
@@ -524,7 +524,7 @@ impl<'a> ExtCtxt<'a> {
     }
 
     pub fn expr_match(&self, span: Span, arg: P<ast::Expr>, arms: ThinVec<ast::Arm>) -> P<Expr> {
-        self.expr(span, ast::ExprKind::Match(arg, arms))
+        self.expr(span, ast::ExprKind::Match(arg, arms, MatchKind::Prefix))
     }
 
     pub fn expr_if(

compiler/rustc_feature/src/unstable.rs

@@ -559,6 +559,8 @@ declare_features! (
     (unstable, offset_of_nested, "1.77.0", Some(120140)),
     /// Allows using `#[optimize(X)]`.
     (unstable, optimize_attribute, "1.34.0", Some(54882)),
+    /// Allows postfix match `expr.match { ... }`
+    (unstable, postfix_match, "CURRENT_RUSTC_VERSION", Some(121618)),
     /// Allows macro attributes on expressions, statements and non-inline modules.
     (unstable, proc_macro_hygiene, "1.30.0", Some(54727)),
     /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.

compiler/rustc_hir/src/hir.rs

@@ -2019,6 +2019,8 @@ pub enum LocalSource {
 pub enum MatchSource {
     /// A `match _ { .. }`.
     Normal,
+    /// A `expr.match { .. }`.
+    Postfix,
     /// A desugared `for _ in _ { .. }` loop.
     ForLoopDesugar,
     /// A desugared `?` operator.
@@ -2035,6 +2037,7 @@ impl MatchSource {
         use MatchSource::*;
         match self {
             Normal => "match",
+            Postfix => ".match",
             ForLoopDesugar => "for",
             TryDesugar(_) => "?",
             AwaitDesugar => ".await",

compiler/rustc_hir_analysis/src/astconv/bounds.rs

@@ -132,16 +132,16 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
                 hir::GenericBound::Trait(poly_trait_ref, modifier) => {
                     let (constness, polarity) = match modifier {
                         hir::TraitBoundModifier::Const => {
-                            (ty::BoundConstness::Const, ty::ImplPolarity::Positive)
+                            (ty::BoundConstness::Const, ty::PredicatePolarity::Positive)
                         }
                         hir::TraitBoundModifier::MaybeConst => {
-                            (ty::BoundConstness::ConstIfConst, ty::ImplPolarity::Positive)
+                            (ty::BoundConstness::ConstIfConst, ty::PredicatePolarity::Positive)
                         }
                         hir::TraitBoundModifier::None => {
-                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Positive)
+                            (ty::BoundConstness::NotConst, ty::PredicatePolarity::Positive)
                         }
                         hir::TraitBoundModifier::Negative => {
-                            (ty::BoundConstness::NotConst, ty::ImplPolarity::Negative)
+                            (ty::BoundConstness::NotConst, ty::PredicatePolarity::Negative)
                         }
                         hir::TraitBoundModifier::Maybe => continue,
                     };

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -645,7 +645,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
         trait_ref: &hir::TraitRef<'tcx>,
         span: Span,
         constness: ty::BoundConstness,
-        polarity: ty::ImplPolarity,
+        polarity: ty::PredicatePolarity,
         self_ty: Ty<'tcx>,
         bounds: &mut Bounds<'tcx>,
         only_self_bounds: OnlySelfBounds,
@@ -682,7 +682,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             // Don't register additional associated type bounds for negative bounds,
             // since we should have emitten an error for them earlier, and they will
             // not be well-formed!
-            if polarity == ty::ImplPolarity::Negative {
+            if polarity != ty::PredicatePolarity::Positive {
                 assert!(
                     self.tcx().dcx().has_errors().is_some(),
                     "negative trait bounds should not have bindings",

compiler/rustc_hir_analysis/src/astconv/object_safety.rs

@@ -41,7 +41,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
                 &trait_bound.trait_ref,
                 trait_bound.span,
                 ty::BoundConstness::NotConst,
-                ty::ImplPolarity::Positive,
+                ty::PredicatePolarity::Positive,
                 dummy_self,
                 &mut bounds,
                 // True so we don't populate `bounds` with associated type bounds, even
@@ -58,7 +58,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             let bound_pred = pred.kind();
             match bound_pred.skip_binder() {
                 ty::ClauseKind::Trait(trait_pred) => {
-                    assert_eq!(trait_pred.polarity, ty::ImplPolarity::Positive);
+                    assert_eq!(trait_pred.polarity, ty::PredicatePolarity::Positive);
                     trait_bounds.push((bound_pred.rebind(trait_pred.trait_ref), span));
                 }
                 ty::ClauseKind::Projection(proj) => {

compiler/rustc_hir_analysis/src/bounds.rs

@@ -42,7 +42,7 @@ impl<'tcx> Bounds<'tcx> {
         tcx: TyCtxt<'tcx>,
         trait_ref: ty::PolyTraitRef<'tcx>,
         span: Span,
-        polarity: ty::ImplPolarity,
+        polarity: ty::PredicatePolarity,
     ) {
         self.push_trait_bound_inner(tcx, trait_ref, span, polarity);
     }
@@ -52,7 +52,7 @@ impl<'tcx> Bounds<'tcx> {
         tcx: TyCtxt<'tcx>,
         trait_ref: ty::PolyTraitRef<'tcx>,
         span: Span,
-        polarity: ty::ImplPolarity,
+        polarity: ty::PredicatePolarity,
     ) {
         self.clauses.push((
             trait_ref

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1322,7 +1322,7 @@ fn check_impl<'tcx>(
                     trait_ref,
                 );
                 let trait_pred =
-                    ty::TraitPredicate { trait_ref, polarity: ty::ImplPolarity::Positive };
+                    ty::TraitPredicate { trait_ref, polarity: ty::PredicatePolarity::Positive };
                 let mut obligations = traits::wf::trait_obligations(
                     wfcx.infcx,
                     wfcx.param_env,