Merging upstream version 1.69.0+dfsg1.

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

2 files changed, 111 insertions, 54 deletions

diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index 43583b572..7f8fc1774 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -25,10 +25,8 @@ use crate::infer::MemberConstraint;
 use crate::mir::ConstraintCategory;
 use crate::ty::subst::GenericArg;
 use crate::ty::{self, BoundVar, List, Region, Ty, TyCtxt};
-use rustc_index::vec::IndexVec;
 use rustc_macros::HashStable;
 use smallvec::SmallVec;
-use std::iter;
 use std::ops::Index;
 
 /// A "canonicalized" type `V` is one where all free inference
@@ -44,12 +42,12 @@ pub struct Canonical<'tcx, V> {
 
 pub type CanonicalVarInfos<'tcx> = &'tcx List<CanonicalVarInfo<'tcx>>;
 
-impl<'tcx> ty::TypeFoldable<'tcx> for CanonicalVarInfos<'tcx> {
-    fn try_fold_with<F: ty::FallibleTypeFolder<'tcx>>(
+impl<'tcx> ty::TypeFoldable<TyCtxt<'tcx>> for CanonicalVarInfos<'tcx> {
+    fn try_fold_with<F: ty::FallibleTypeFolder<TyCtxt<'tcx>>>(
         self,
         folder: &mut F,
     ) -> Result<Self, F::Error> {
-        ty::util::fold_list(self, folder, |tcx, v| tcx.intern_canonical_var_infos(v))
+        ty::util::fold_list(self, folder, |tcx, v| tcx.mk_canonical_var_infos(v))
     }
 }
 
@@ -62,23 +60,23 @@ impl<'tcx> ty::TypeFoldable<'tcx> for CanonicalVarInfos<'tcx> {
 /// vectors with the original values that were replaced by canonical
 /// variables. You will need to supply it later to instantiate the
 /// canonicalized query response.
-#[derive(Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TyDecodable, TyEncodable)]
 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct CanonicalVarValues<'tcx> {
-    pub var_values: IndexVec<BoundVar, GenericArg<'tcx>>,
+    pub var_values: ty::SubstsRef<'tcx>,
 }
 
 impl CanonicalVarValues<'_> {
     pub fn is_identity(&self) -> bool {
-        self.var_values.iter_enumerated().all(|(bv, arg)| match arg.unpack() {
+        self.var_values.iter().enumerate().all(|(bv, arg)| match arg.unpack() {
             ty::GenericArgKind::Lifetime(r) => {
-                matches!(*r, ty::ReLateBound(ty::INNERMOST, br) if br.var == bv)
+                matches!(*r, ty::ReLateBound(ty::INNERMOST, br) if br.var.as_usize() == bv)
             }
             ty::GenericArgKind::Type(ty) => {
-                matches!(*ty.kind(), ty::Bound(ty::INNERMOST, bt) if bt.var == bv)
+                matches!(*ty.kind(), ty::Bound(ty::INNERMOST, bt) if bt.var.as_usize() == bv)
             }
             ty::GenericArgKind::Const(ct) => {
-                matches!(ct.kind(), ty::ConstKind::Bound(ty::INNERMOST, bc) if bc == bv)
+                matches!(ct.kind(), ty::ConstKind::Bound(ty::INNERMOST, bc) if bc.as_usize() == bv)
             }
         })
     }
@@ -125,6 +123,11 @@ impl<'tcx> CanonicalVarInfo<'tcx> {
         self.kind.universe()
     }
 
+    #[must_use]
+    pub fn with_updated_universe(self, ui: ty::UniverseIndex) -> CanonicalVarInfo<'tcx> {
+        CanonicalVarInfo { kind: self.kind.with_updated_universe(ui) }
+    }
+
     pub fn is_existential(&self) -> bool {
         match self.kind {
             CanonicalVarKind::Ty(_) => true,
@@ -135,6 +138,28 @@ impl<'tcx> CanonicalVarInfo<'tcx> {
             CanonicalVarKind::PlaceholderConst(_, _) => false,
         }
     }
+
+    pub fn is_region(&self) -> bool {
+        match self.kind {
+            CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => true,
+            CanonicalVarKind::Ty(_)
+            | CanonicalVarKind::PlaceholderTy(_)
+            | CanonicalVarKind::Const(_, _)
+            | CanonicalVarKind::PlaceholderConst(_, _) => false,
+        }
+    }
+
+    pub fn expect_anon_placeholder(self) -> u32 {
+        match self.kind {
+            CanonicalVarKind::Ty(_)
+            | CanonicalVarKind::Region(_)
+            | CanonicalVarKind::Const(_, _) => bug!("expected placeholder: {self:?}"),
+
+            CanonicalVarKind::PlaceholderRegion(placeholder) => placeholder.name.expect_anon(),
+            CanonicalVarKind::PlaceholderTy(placeholder) => placeholder.name.expect_anon(),
+            CanonicalVarKind::PlaceholderConst(placeholder, _) => placeholder.name.as_u32(),
+        }
+    }
 }
 
 /// Describes the "kind" of the canonical variable. This is a "kind"
@@ -179,6 +204,38 @@ impl<'tcx> CanonicalVarKind<'tcx> {
             CanonicalVarKind::PlaceholderConst(placeholder, _) => placeholder.universe,
         }
     }
+
+    /// Replaces the universe of this canonical variable with `ui`.
+    ///
+    /// In case this is a float or int variable, this causes an ICE if
+    /// the updated universe is not the root.
+    pub fn with_updated_universe(self, ui: ty::UniverseIndex) -> CanonicalVarKind<'tcx> {
+        match self {
+            CanonicalVarKind::Ty(kind) => match kind {
+                CanonicalTyVarKind::General(_) => {
+                    CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui))
+                }
+                CanonicalTyVarKind::Int | CanonicalTyVarKind::Float => {
+                    assert_eq!(ui, ty::UniverseIndex::ROOT);
+                    CanonicalVarKind::Ty(kind)
+                }
+            },
+            CanonicalVarKind::PlaceholderTy(placeholder) => {
+                CanonicalVarKind::PlaceholderTy(ty::Placeholder { universe: ui, ..placeholder })
+            }
+            CanonicalVarKind::Region(_) => CanonicalVarKind::Region(ui),
+            CanonicalVarKind::PlaceholderRegion(placeholder) => {
+                CanonicalVarKind::PlaceholderRegion(ty::Placeholder { universe: ui, ..placeholder })
+            }
+            CanonicalVarKind::Const(_, ty) => CanonicalVarKind::Const(ui, ty),
+            CanonicalVarKind::PlaceholderConst(placeholder, ty) => {
+                CanonicalVarKind::PlaceholderConst(
+                    ty::Placeholder { universe: ui, ..placeholder },
+                    ty,
+                )
+            }
+        }
+    }
 }
 
 /// Rust actually has more than one category of type variables;
@@ -215,7 +272,8 @@ pub struct QueryResponse<'tcx, R> {
     pub value: R,
 }
 
-#[derive(Clone, Debug, Default, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Clone, Debug, Default, PartialEq, Eq, Hash)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct QueryRegionConstraints<'tcx> {
     pub outlives: Vec<QueryOutlivesConstraint<'tcx>>,
     pub member_constraints: Vec<MemberConstraint<'tcx>>,
@@ -326,10 +384,8 @@ impl<'tcx, V> Canonical<'tcx, V> {
     }
 }
 
-pub type QueryOutlivesConstraint<'tcx> = (
-    ty::Binder<'tcx, ty::OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>>,
-    ConstraintCategory<'tcx>,
-);
+pub type QueryOutlivesConstraint<'tcx> =
+    (ty::OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>, ConstraintCategory<'tcx>);
 
 TrivialTypeTraversalAndLiftImpls! {
     for <'tcx> {
@@ -339,57 +395,57 @@ TrivialTypeTraversalAndLiftImpls! {
 }
 
 impl<'tcx> CanonicalVarValues<'tcx> {
+    // Given a list of canonical variables, construct a set of values which are
+    // the identity response.
+    pub fn make_identity(
+        tcx: TyCtxt<'tcx>,
+        infos: CanonicalVarInfos<'tcx>,
+    ) -> CanonicalVarValues<'tcx> {
+        CanonicalVarValues {
+            var_values: tcx.mk_substs_from_iter(infos.iter().enumerate().map(
+                |(i, info)| -> ty::GenericArg<'tcx> {
+                    match info.kind {
+                        CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
+                            tcx.mk_bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into()).into()
+                        }
+                        CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
+                            let br = ty::BoundRegion {
+                                var: ty::BoundVar::from_usize(i),
+                                kind: ty::BrAnon(i as u32, None),
+                            };
+                            tcx.mk_re_late_bound(ty::INNERMOST, br).into()
+                        }
+                        CanonicalVarKind::Const(_, ty)
+                        | CanonicalVarKind::PlaceholderConst(_, ty) => tcx
+                            .mk_const(
+                                ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i)),
+                                ty,
+                            )
+                            .into(),
+                    }
+                },
+            )),
+        }
+    }
+
     /// Creates dummy var values which should not be used in a
     /// canonical response.
     pub fn dummy() -> CanonicalVarValues<'tcx> {
-        CanonicalVarValues { var_values: Default::default() }
+        CanonicalVarValues { var_values: ty::List::empty() }
     }
 
     #[inline]
     pub fn len(&self) -> usize {
         self.var_values.len()
     }
-
-    /// Makes an identity substitution from this one: each bound var
-    /// is matched to the same bound var, preserving the original kinds.
-    /// For example, if we have:
-    /// `self.var_values == [Type(u32), Lifetime('a), Type(u64)]`
-    /// we'll return a substitution `subst` with:
-    /// `subst.var_values == [Type(^0), Lifetime(^1), Type(^2)]`.
-    pub fn make_identity(&self, tcx: TyCtxt<'tcx>) -> Self {
-        use crate::ty::subst::GenericArgKind;
-
-        CanonicalVarValues {
-            var_values: iter::zip(&self.var_values, 0..)
-                .map(|(kind, i)| match kind.unpack() {
-                    GenericArgKind::Type(..) => {
-                        tcx.mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_u32(i).into())).into()
-                    }
-                    GenericArgKind::Lifetime(..) => {
-                        let br = ty::BoundRegion {
-                            var: ty::BoundVar::from_u32(i),
-                            kind: ty::BrAnon(i, None),
-                        };
-                        tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)).into()
-                    }
-                    GenericArgKind::Const(ct) => tcx
-                        .mk_const(
-                            ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_u32(i)),
-                            ct.ty(),
-                        )
-                        .into(),
-                })
-                .collect(),
-        }
-    }
 }
 
 impl<'a, 'tcx> IntoIterator for &'a CanonicalVarValues<'tcx> {
     type Item = GenericArg<'tcx>;
-    type IntoIter = ::std::iter::Cloned<::std::slice::Iter<'a, GenericArg<'tcx>>>;
+    type IntoIter = ::std::iter::Copied<::std::slice::Iter<'a, GenericArg<'tcx>>>;
 
     fn into_iter(self) -> Self::IntoIter {
-        self.var_values.iter().cloned()
+        self.var_values.iter()
     }
 }
 
@@ -397,6 +453,6 @@ impl<'tcx> Index<BoundVar> for CanonicalVarValues<'tcx> {
     type Output = GenericArg<'tcx>;
 
     fn index(&self, value: BoundVar) -> &GenericArg<'tcx> {
-        &self.var_values[value]
+        &self.var_values[value.as_usize()]
     }
 }
diff --git a/compiler/rustc_middle/src/infer/mod.rs b/compiler/rustc_middle/src/infer/mod.rs
index 38868c210..2db59f37f 100644
--- a/compiler/rustc_middle/src/infer/mod.rs
+++ b/compiler/rustc_middle/src/infer/mod.rs
@@ -12,7 +12,8 @@ use rustc_span::Span;
 /// ```text
 /// R0 member of [O1..On]
 /// ```
-#[derive(Debug, Clone, HashStable, TypeFoldable, TypeVisitable, Lift)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct MemberConstraint<'tcx> {
     /// The `DefId` and substs of the opaque type causing this constraint.
     /// Used for error reporting.