Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 101 insertions, 124 deletions

diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 6baf8c7d7..304870274 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -157,7 +157,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     /// [ 0. Pre-match ]
     ///        |
     /// [ 1. Evaluate Scrutinee (expression being matched on) ]
-    /// [ (fake read of scrutinee) ]
+    /// [ (PlaceMention of scrutinee) ]
     ///        |
     /// [ 2. Decision tree -- check discriminants ] <--------+
     ///        |                                             |
@@ -184,7 +184,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
     ///
     /// We generate MIR in the following steps:
     ///
-    /// 1. Evaluate the scrutinee and add the fake read of it ([Builder::lower_scrutinee]).
+    /// 1. Evaluate the scrutinee and add the PlaceMention of it ([Builder::lower_scrutinee]).
     /// 2. Create the decision tree ([Builder::lower_match_tree]).
     /// 3. Determine the fake borrows that are needed from the places that were
     ///    matched against and create the required temporaries for them
@@ -223,6 +223,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let fake_borrow_temps = self.lower_match_tree(
             block,
             scrutinee_span,
+            &scrutinee_place,
             match_start_span,
             match_has_guard,
             &mut candidates,
@@ -238,7 +239,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         )
     }
 
-    /// Evaluate the scrutinee and add the fake read of it.
+    /// Evaluate the scrutinee and add the PlaceMention for it.
     fn lower_scrutinee(
         &mut self,
         mut block: BasicBlock,
@@ -246,26 +247,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         scrutinee_span: Span,
     ) -> BlockAnd<PlaceBuilder<'tcx>> {
         let scrutinee_place_builder = unpack!(block = self.as_place_builder(block, scrutinee));
-        // Matching on a `scrutinee_place` with an uninhabited type doesn't
-        // generate any memory reads by itself, and so if the place "expression"
-        // contains unsafe operations like raw pointer dereferences or union
-        // field projections, we wouldn't know to require an `unsafe` block
-        // around a `match` equivalent to `std::intrinsics::unreachable()`.
-        // See issue #47412 for this hole being discovered in the wild.
-        //
-        // HACK(eddyb) Work around the above issue by adding a dummy inspection
-        // of `scrutinee_place`, specifically by applying `ReadForMatch`.
-        //
-        // NOTE: ReadForMatch also checks that the scrutinee is initialized.
-        // This is currently needed to not allow matching on an uninitialized,
-        // uninhabited value. If we get never patterns, those will check that
-        // the place is initialized, and so this read would only be used to
-        // check safety.
-        let cause_matched_place = FakeReadCause::ForMatchedPlace(None);
-        let source_info = self.source_info(scrutinee_span);
-
         if let Some(scrutinee_place) = scrutinee_place_builder.try_to_place(self) {
-            self.cfg.push_fake_read(block, source_info, cause_matched_place, scrutinee_place);
+            let source_info = self.source_info(scrutinee_span);
+            self.cfg.push_place_mention(block, source_info, scrutinee_place);
         }
 
         block.and(scrutinee_place_builder)
@@ -304,6 +288,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         block: BasicBlock,
         scrutinee_span: Span,
+        scrutinee_place_builder: &PlaceBuilder<'tcx>,
         match_start_span: Span,
         match_has_guard: bool,
         candidates: &mut [&mut Candidate<'pat, 'tcx>],
@@ -331,6 +316,33 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             // otherwise block. Match checking will ensure this is actually
             // unreachable.
             let source_info = self.source_info(scrutinee_span);
+
+            // Matching on a `scrutinee_place` with an uninhabited type doesn't
+            // generate any memory reads by itself, and so if the place "expression"
+            // contains unsafe operations like raw pointer dereferences or union
+            // field projections, we wouldn't know to require an `unsafe` block
+            // around a `match` equivalent to `std::intrinsics::unreachable()`.
+            // See issue #47412 for this hole being discovered in the wild.
+            //
+            // HACK(eddyb) Work around the above issue by adding a dummy inspection
+            // of `scrutinee_place`, specifically by applying `ReadForMatch`.
+            //
+            // NOTE: ReadForMatch also checks that the scrutinee is initialized.
+            // This is currently needed to not allow matching on an uninitialized,
+            // uninhabited value. If we get never patterns, those will check that
+            // the place is initialized, and so this read would only be used to
+            // check safety.
+            let cause_matched_place = FakeReadCause::ForMatchedPlace(None);
+
+            if let Some(scrutinee_place) = scrutinee_place_builder.try_to_place(self) {
+                self.cfg.push_fake_read(
+                    otherwise_block,
+                    source_info,
+                    cause_matched_place,
+                    scrutinee_place,
+                );
+            }
+
             self.cfg.terminate(otherwise_block, source_info, TerminatorKind::Unreachable);
         }
 
@@ -599,13 +611,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
 
             _ => {
-                let place_builder = unpack!(block = self.as_place_builder(block, initializer));
-
-                if let Some(place) = place_builder.try_to_place(self) {
-                    let source_info = self.source_info(initializer.span);
-                    self.cfg.push_place_mention(block, source_info, place);
-                }
-
+                let place_builder =
+                    unpack!(block = self.lower_scrutinee(block, initializer, initializer.span));
                 self.place_into_pattern(block, &irrefutable_pat, place_builder, true)
             }
         }
@@ -622,6 +629,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let fake_borrow_temps = self.lower_match_tree(
             block,
             irrefutable_pat.span,
+            &initializer,
             irrefutable_pat.span,
             false,
             &mut [&mut candidate],
@@ -736,7 +744,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         self.cfg.push(block, Statement { source_info, kind: StatementKind::StorageLive(local_id) });
         // Although there is almost always scope for given variable in corner cases
         // like #92893 we might get variable with no scope.
-        if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id) && schedule_drop {
+        if let Some(region_scope) = self.region_scope_tree.var_scope(var.0.local_id)
+            && schedule_drop
+        {
             self.schedule_drop(span, region_scope, local_id, DropKind::Storage);
         }
         Place::from(local_id)
@@ -814,7 +824,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            PatKind::Constant { .. } | PatKind::Range { .. } | PatKind::Wild => {}
+            PatKind::Constant { .. }
+            | PatKind::Range { .. }
+            | PatKind::Wild
+            | PatKind::Error(_) => {}
 
             PatKind::Deref { ref subpattern } => {
                 self.visit_primary_bindings(subpattern, pattern_user_ty.deref(), f);
@@ -842,6 +855,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 self.visit_primary_bindings(subpattern, subpattern_user_ty, f)
             }
 
+            PatKind::InlineConstant { ref subpattern, .. } => {
+                self.visit_primary_bindings(subpattern, pattern_user_ty, f)
+            }
+
             PatKind::Leaf { ref subpatterns } => {
                 for subpattern in subpatterns {
                     let subpattern_user_ty = pattern_user_ty.clone().leaf(subpattern.field);
@@ -1018,7 +1035,7 @@ enum TestKind<'tcx> {
         ty: Ty<'tcx>,
     },
 
-    /// Test whether the value falls within an inclusive or exclusive range
+    /// Test whether the value falls within an inclusive or exclusive range.
     Range(Box<PatRange<'tcx>>),
 
     /// Test that the length of the slice is equal to `len`.
@@ -1798,7 +1815,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let fake_borrow_ty =
                     Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, fake_borrow_deref_ty);
                 let mut fake_borrow_temp = LocalDecl::new(fake_borrow_ty, temp_span);
-                fake_borrow_temp.internal = self.local_decls[matched_place.local].internal;
                 fake_borrow_temp.local_info = ClearCrossCrate::Set(Box::new(LocalInfo::FakeBorrow));
                 let fake_borrow_temp = self.local_decls.push(fake_borrow_temp);
 
@@ -1833,6 +1849,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         let fake_borrow_temps = self.lower_match_tree(
             block,
             pat.span,
+            &expr_place_builder,
             pat.span,
             false,
             &mut [&mut guard_candidate, &mut otherwise_candidate],
@@ -2268,7 +2285,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ty: var_ty,
             user_ty: if user_ty.is_empty() { None } else { Some(Box::new(user_ty)) },
             source_info,
-            internal: false,
             local_info: ClearCrossCrate::Set(Box::new(LocalInfo::User(BindingForm::Var(
                 VarBindingForm {
                     binding_mode,
@@ -2298,7 +2314,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 ty: Ty::new_imm_ref(tcx, tcx.lifetimes.re_erased, var_ty),
                 user_ty: None,
                 source_info,
-                internal: false,
                 local_info: ClearCrossCrate::Set(Box::new(LocalInfo::User(
                     BindingForm::RefForGuard,
                 ))),
@@ -2336,6 +2351,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             let fake_borrow_temps = this.lower_match_tree(
                 block,
                 initializer_span,
+                &scrutinee,
                 pattern.span,
                 false,
                 &mut [&mut candidate, &mut wildcard],
diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs
index 17ac1f4e0..6a40c8d84 100644
--- a/compiler/rustc_mir_build/src/build/matches/simplify.rs
+++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs
@@ -15,11 +15,7 @@
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::matches::{Ascription, Binding, Candidate, MatchPair};
 use crate::build::Builder;
-use rustc_hir::RangeEnd;
 use rustc_middle::thir::{self, *};
-use rustc_middle::ty;
-use rustc_middle::ty::layout::IntegerExt;
-use rustc_target::abi::{Integer, Size};
 
 use std::mem;
 
@@ -148,7 +144,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         match_pair: MatchPair<'pat, 'tcx>,
         candidate: &mut Candidate<'pat, 'tcx>,
     ) -> Result<(), MatchPair<'pat, 'tcx>> {
-        let tcx = self.tcx;
         match match_pair.pattern.kind {
             PatKind::AscribeUserType {
                 ref subpattern,
@@ -168,7 +163,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Ok(())
             }
 
-            PatKind::Wild => {
+            PatKind::Wild | PatKind::Error(_) => {
                 // nothing left to do
                 Ok(())
             }
@@ -204,41 +199,16 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Err(match_pair)
             }
 
-            PatKind::Range(box PatRange { lo, hi, end }) => {
-                let (range, bias) = match *lo.ty().kind() {
-                    ty::Char => {
-                        (Some(('\u{0000}' as u128, '\u{10FFFF}' as u128, Size::from_bits(32))), 0)
-                    }
-                    ty::Int(ity) => {
-                        let size = Integer::from_int_ty(&tcx, ity).size();
-                        let max = size.truncate(u128::MAX);
-                        let bias = 1u128 << (size.bits() - 1);
-                        (Some((0, max, size)), bias)
-                    }
-                    ty::Uint(uty) => {
-                        let size = Integer::from_uint_ty(&tcx, uty).size();
-                        let max = size.truncate(u128::MAX);
-                        (Some((0, max, size)), 0)
-                    }
-                    _ => (None, 0),
-                };
-                if let Some((min, max, sz)) = range {
-                    // We want to compare ranges numerically, but the order of the bitwise
-                    // representation of signed integers does not match their numeric order. Thus,
-                    // to correct the ordering, we need to shift the range of signed integers to
-                    // correct the comparison. This is achieved by XORing with a bias (see
-                    // pattern/_match.rs for another pertinent example of this pattern).
-                    //
-                    // Also, for performance, it's important to only do the second `try_to_bits` if
-                    // necessary.
-                    let lo = lo.try_to_bits(sz).unwrap() ^ bias;
-                    if lo <= min {
-                        let hi = hi.try_to_bits(sz).unwrap() ^ bias;
-                        if hi > max || hi == max && end == RangeEnd::Included {
-                            // Irrefutable pattern match.
-                            return Ok(());
-                        }
-                    }
+            PatKind::InlineConstant { subpattern: ref pattern, def: _ } => {
+                candidate.match_pairs.push(MatchPair::new(match_pair.place, pattern, self));
+
+                Ok(())
+            }
+
+            PatKind::Range(ref range) => {
+                if let Some(true) = range.is_full_range(self.tcx) {
+                    // Irrefutable pattern match.
+                    return Ok(());
                 }
                 Err(match_pair)
             }
diff --git a/compiler/rustc_mir_build/src/build/matches/test.rs b/compiler/rustc_mir_build/src/build/matches/test.rs
index 795d1db8e..bdd4f2011 100644
--- a/compiler/rustc_mir_build/src/build/matches/test.rs
+++ b/compiler/rustc_mir_build/src/build/matches/test.rs
@@ -8,7 +8,6 @@
 use crate::build::expr::as_place::PlaceBuilder;
 use crate::build::matches::{Candidate, MatchPair, Test, TestKind};
 use crate::build::Builder;
-use crate::thir::pattern::compare_const_vals;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_hir::{LangItem, RangeEnd};
 use rustc_index::bit_set::BitSet;
@@ -59,8 +58,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             },
 
             PatKind::Range(ref range) => {
-                assert_eq!(range.lo.ty(), match_pair.pattern.ty);
-                assert_eq!(range.hi.ty(), match_pair.pattern.ty);
+                assert_eq!(range.ty, match_pair.pattern.ty);
                 Test { span: match_pair.pattern.span, kind: TestKind::Range(range.clone()) }
             }
 
@@ -73,11 +71,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             PatKind::Or { .. } => bug!("or-patterns should have already been handled"),
 
             PatKind::AscribeUserType { .. }
+            | PatKind::InlineConstant { .. }
             | PatKind::Array { .. }
             | PatKind::Wild
             | PatKind::Binding { .. }
             | PatKind::Leaf { .. }
-            | PatKind::Deref { .. } => self.error_simplifiable(match_pair),
+            | PatKind::Deref { .. }
+            | PatKind::Error(_) => self.error_simplifiable(match_pair),
         }
     }
 
@@ -110,8 +110,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             | PatKind::Or { .. }
             | PatKind::Binding { .. }
             | PatKind::AscribeUserType { .. }
+            | PatKind::InlineConstant { .. }
             | PatKind::Leaf { .. }
-            | PatKind::Deref { .. } => {
+            | PatKind::Deref { .. }
+            | PatKind::Error(_) => {
                 // don't know how to add these patterns to a switch
                 false
             }
@@ -236,18 +238,27 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
 
             TestKind::Eq { value, ty } => {
                 let tcx = self.tcx;
-                if let ty::Adt(def, _) = ty.kind() && Some(def.did()) == tcx.lang_items().string() {
+                if let ty::Adt(def, _) = ty.kind()
+                    && Some(def.did()) == tcx.lang_items().string()
+                {
                     if !tcx.features().string_deref_patterns {
-                        bug!("matching on `String` went through without enabling string_deref_patterns");
+                        bug!(
+                            "matching on `String` went through without enabling string_deref_patterns"
+                        );
                     }
                     let re_erased = tcx.lifetimes.re_erased;
-                    let ref_string = self.temp(Ty::new_imm_ref(tcx,re_erased, ty), test.span);
-                    let ref_str_ty = Ty::new_imm_ref(tcx,re_erased, tcx.types.str_);
+                    let ref_string = self.temp(Ty::new_imm_ref(tcx, re_erased, ty), test.span);
+                    let ref_str_ty = Ty::new_imm_ref(tcx, re_erased, tcx.types.str_);
                     let ref_str = self.temp(ref_str_ty, test.span);
                     let deref = tcx.require_lang_item(LangItem::Deref, None);
                     let method = trait_method(tcx, deref, sym::deref, [ty]);
                     let eq_block = self.cfg.start_new_block();
-                    self.cfg.push_assign(block, source_info, ref_string, Rvalue::Ref(re_erased, BorrowKind::Shared, place));
+                    self.cfg.push_assign(
+                        block,
+                        source_info,
+                        ref_string,
+                        Rvalue::Ref(re_erased, BorrowKind::Shared, place),
+                    );
                     self.cfg.terminate(
                         block,
                         source_info,
@@ -262,10 +273,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             target: Some(eq_block),
                             unwind: UnwindAction::Continue,
                             call_source: CallSource::Misc,
-                            fn_span: source_info.span
-                        }
+                            fn_span: source_info.span,
+                        },
+                    );
+                    self.non_scalar_compare(
+                        eq_block,
+                        make_target_blocks,
+                        source_info,
+                        value,
+                        ref_str,
+                        ref_str_ty,
                     );
-                    self.non_scalar_compare(eq_block, make_target_blocks, source_info, value, ref_str, ref_str_ty);
                     return;
                 }
                 if !ty.is_scalar() {
@@ -289,11 +307,14 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 }
             }
 
-            TestKind::Range(box PatRange { lo, hi, ref end }) => {
+            TestKind::Range(ref range) => {
                 let lower_bound_success = self.cfg.start_new_block();
                 let target_blocks = make_target_blocks(self);
 
                 // Test `val` by computing `lo <= val && val <= hi`, using primitive comparisons.
+                // FIXME: skip useless comparison when the range is half-open.
+                let lo = range.lo.to_const(range.ty, self.tcx);
+                let hi = range.hi.to_const(range.ty, self.tcx);
                 let lo = self.literal_operand(test.span, lo);
                 let hi = self.literal_operand(test.span, hi);
                 let val = Operand::Copy(place);
@@ -310,7 +331,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     lo,
                     val.clone(),
                 );
-                let op = match *end {
+                let op = match range.end {
                     RangeEnd::Included => BinOp::Le,
                     RangeEnd::Excluded => BinOp::Lt,
                 };
@@ -678,34 +699,18 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
 
             (TestKind::Range(test), PatKind::Range(pat)) => {
-                use std::cmp::Ordering::*;
-
                 if test == pat {
                     self.candidate_without_match_pair(match_pair_index, candidate);
                     return Some(0);
                 }
 
-                // For performance, it's important to only do the second
-                // `compare_const_vals` if necessary.
-                let no_overlap = if matches!(
-                    (compare_const_vals(self.tcx, test.hi, pat.lo, self.param_env)?, test.end),
-                    (Less, _) | (Equal, RangeEnd::Excluded) // test < pat
-                ) || matches!(
-                    (compare_const_vals(self.tcx, test.lo, pat.hi, self.param_env)?, pat.end),
-                    (Greater, _) | (Equal, RangeEnd::Excluded) // test > pat
-                ) {
-                    Some(1)
-                } else {
-                    None
-                };
-
                 // If the testing range does not overlap with pattern range,
                 // the pattern can be matched only if this test fails.
-                no_overlap
+                if !test.overlaps(pat, self.tcx, self.param_env)? { Some(1) } else { None }
             }
 
             (TestKind::Range(range), &PatKind::Constant { value }) => {
-                if let Some(false) = self.const_range_contains(&*range, value) {
+                if !range.contains(value, self.tcx, self.param_env)? {
                     // `value` is not contained in the testing range,
                     // so `value` can be matched only if this test fails.
                     Some(1)
@@ -797,27 +802,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         span_bug!(match_pair.pattern.span, "simplifiable pattern found: {:?}", match_pair.pattern)
     }
 
-    fn const_range_contains(&self, range: &PatRange<'tcx>, value: Const<'tcx>) -> Option<bool> {
-        use std::cmp::Ordering::*;
-
-        // For performance, it's important to only do the second
-        // `compare_const_vals` if necessary.
-        Some(
-            matches!(compare_const_vals(self.tcx, range.lo, value, self.param_env)?, Less | Equal)
-                && matches!(
-                    (compare_const_vals(self.tcx, value, range.hi, self.param_env)?, range.end),
-                    (Less, _) | (Equal, RangeEnd::Included)
-                ),
-        )
-    }
-
     fn values_not_contained_in_range(
         &self,
         range: &PatRange<'tcx>,
         options: &FxIndexMap<Const<'tcx>, u128>,
     ) -> Option<bool> {
         for &val in options.keys() {
-            if self.const_range_contains(range, val)? {
+            if range.contains(val, self.tcx, self.param_env)? {
                 return Some(false);
             }
         }