summaryrefslogtreecommitdiffstats
path: root/vendor/chalk-ir
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:18:21 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:18:21 +0000
commit4e8199b572f2035b7749cba276ece3a26630d23e (patch)
treef09feeed6a0fe39d027b1908aa63ea6b35e4b631 /vendor/chalk-ir
parentAdding upstream version 1.66.0+dfsg1. (diff)
downloadrustc-4e8199b572f2035b7749cba276ece3a26630d23e.tar.xz
rustc-4e8199b572f2035b7749cba276ece3a26630d23e.zip
Adding upstream version 1.67.1+dfsg1.upstream/1.67.1+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/chalk-ir')
-rw-r--r--vendor/chalk-ir/.cargo-checksum.json1
-rw-r--r--vendor/chalk-ir/Cargo.toml37
-rw-r--r--vendor/chalk-ir/README.md3
-rw-r--r--vendor/chalk-ir/src/cast.rs364
-rw-r--r--vendor/chalk-ir/src/could_match.rs213
-rw-r--r--vendor/chalk-ir/src/debug.rs1016
-rw-r--r--vendor/chalk-ir/src/fold.rs920
-rw-r--r--vendor/chalk-ir/src/fold/binder_impls.rs73
-rw-r--r--vendor/chalk-ir/src/fold/boring_impls.rs244
-rw-r--r--vendor/chalk-ir/src/fold/in_place.rs263
-rw-r--r--vendor/chalk-ir/src/fold/shift.rs177
-rw-r--r--vendor/chalk-ir/src/fold/subst.rs118
-rw-r--r--vendor/chalk-ir/src/interner.rs702
-rw-r--r--vendor/chalk-ir/src/lib.rs3055
-rw-r--r--vendor/chalk-ir/src/visit.rs422
-rw-r--r--vendor/chalk-ir/src/visit/binder_impls.rs47
-rw-r--r--vendor/chalk-ir/src/visit/boring_impls.rs261
-rw-r--r--vendor/chalk-ir/src/visit/visitors.rs41
-rw-r--r--vendor/chalk-ir/src/zip.rs543
19 files changed, 8500 insertions, 0 deletions
diff --git a/vendor/chalk-ir/.cargo-checksum.json b/vendor/chalk-ir/.cargo-checksum.json
new file mode 100644
index 000000000..7b2915873
--- /dev/null
+++ b/vendor/chalk-ir/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"ccde3a8b1652787636f0a34b43eb557bfce1e7e9a92b4634a6f666e512d8d491","README.md":"64cba0ddf3e9b5c168fbe069f1a84c401ce0b33e765ea49acb1345d0923afe8d","src/cast.rs":"b2a6dc2fe33d58df3021d1e83f3823d68a14afff2a484fe0a5c8514290112c17","src/could_match.rs":"a341b8b11615ca738498c722b61695307da170f14754c281fbf2b778d3e82348","src/debug.rs":"63c152c41ae1adcdd1cca725162bef1b42e19307d3b4dfc228d43743d6c6daf2","src/fold.rs":"aa00b9aed253895eb532ba0f89dfb5e971743ea258437cea492c2f90f01c9b23","src/fold/binder_impls.rs":"47ee10eac8081e15148a43e9a1dae32712b0b14d565c9ed5082985abda9302a4","src/fold/boring_impls.rs":"6958c7d0d8315d6864b4d2ec4638544567d6262e1f50fb28df02ac1d57804d90","src/fold/in_place.rs":"83bf2fb5d2b6d8fcd7a2389779329cfc72e83b223eb9dac899635e2deab5a9c9","src/fold/shift.rs":"4119c8e3bb40279ab416ace3bea2137fc917440bb50b37c870c56f9351d508db","src/fold/subst.rs":"6254d62b2bf92d8114384701734a53780119836b0aaf87392dda161ea7b93526","src/interner.rs":"41f5780894b29542db0f7a46386e60f321c527bfd02cbf5be89b45be14a4dc3c","src/lib.rs":"e7fd2eab6a8cae0b0e8bce4b2a0fcb7a67da991755b11d9e9351ba2ec0cf5f87","src/visit.rs":"c914621e2bb77290b3d064cd52d4703ad438daa0c167f8fe0c3fb696a2674b84","src/visit/binder_impls.rs":"9afc460830fd9de249c4120461624432edf715e8661cf28c36e9f2ff47e2a13e","src/visit/boring_impls.rs":"412cdfc9f78edf3a5f6d6ad2f60e21087263c74bca1236420115608333ae9704","src/visit/visitors.rs":"3af422b5179a364483575eec03d68cb277a308508b89a19915f4d76aed9dc696","src/zip.rs":"d86c20f0d44ecf6dae9dae02540d0beb04081a7721337a9dfa3c1b0a4b8cb4f7"},"package":"43aa55deff4e7fbdb09fa014543372f2c95a06835ac487b9ce57b5099b950838"} \ No newline at end of file
diff --git a/vendor/chalk-ir/Cargo.toml b/vendor/chalk-ir/Cargo.toml
new file mode 100644
index 000000000..16e1e83b2
--- /dev/null
+++ b/vendor/chalk-ir/Cargo.toml
@@ -0,0 +1,37 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2018"
+name = "chalk-ir"
+version = "0.87.0"
+authors = [
+ "Rust Compiler Team",
+ "Chalk developers",
+]
+description = "Chalk's internal representation of types, goals, and clauses"
+readme = "README.md"
+keywords = [
+ "compiler",
+ "traits",
+ "prolog",
+]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/rust-lang/chalk"
+
+[dependencies.bitflags]
+version = "1.2.1"
+
+[dependencies.chalk-derive]
+version = "=0.87.0"
+
+[dependencies.lazy_static]
+version = "1.4.0"
diff --git a/vendor/chalk-ir/README.md b/vendor/chalk-ir/README.md
new file mode 100644
index 000000000..968ad4937
--- /dev/null
+++ b/vendor/chalk-ir/README.md
@@ -0,0 +1,3 @@
+A rust type library for chalk.
+
+See [Github](https://github.com/rust-lang/chalk) for up-to-date information.
diff --git a/vendor/chalk-ir/src/cast.rs b/vendor/chalk-ir/src/cast.rs
new file mode 100644
index 000000000..0c6b682ca
--- /dev/null
+++ b/vendor/chalk-ir/src/cast.rs
@@ -0,0 +1,364 @@
+//! Upcasts, to avoid writing out wrapper types.
+
+use crate::*;
+use std::marker::PhantomData;
+
+/// The `Cast` trait is used to make annoying upcasts between
+/// logically equivalent types that imply wrappers. For example, one
+/// could convert a `DomainGoal` into a `Goal` by doing:
+///
+/// ```ignore
+/// let goal: Goal = domain_goal.cast();
+/// ```
+///
+/// This is equivalent to the more explicit:
+///
+/// ```ignore
+/// let goal: Goal = Goal::DomainGoal(domain_goal)
+/// ```
+///
+/// Another useful trick is the `casted()` iterator adapter, which
+/// casts each element in the iterator as it is produced (you must
+/// have the `Caster` trait in scope for that).
+///
+/// # Invariant
+///
+/// `Cast` imposes a key invariant. You can only implement `T:
+/// Cast<U>` if both `T` and `U` have the same semantic meaning. Also,
+/// as part of this, they should always use the same set of free
+/// variables (the `Canonical` implementation, for example, relies on
+/// that).
+///
+/// # Iterators
+///
+/// If you import the `Caster` trait, you can also write `.casted()` on an
+/// iterator chain to cast every instance within.
+///
+/// # Implementing Cast
+///
+/// Do not implement `Cast` directly. Instead, implement `CastTo`.
+/// This split setup allows us to write `foo.cast::<T>()` to mean
+/// "cast to T".
+pub trait Cast: Sized {
+ /// Cast a value to type `U` using `CastTo`.
+ fn cast<U>(self, interner: U::Interner) -> U
+ where
+ Self: CastTo<U>,
+ U: HasInterner,
+ {
+ self.cast_to(interner)
+ }
+}
+
+impl<T> Cast for T {}
+
+/// The "helper" trait for `cast` that actually implements the
+/// transformations. You can also use this if you want to have
+/// functions that take (e.g.) an `impl CastTo<Goal<_>>` or something
+/// like that.
+pub trait CastTo<T: HasInterner>: Sized {
+ /// Cast a value to type `T`.
+ fn cast_to(self, interner: T::Interner) -> T;
+}
+
+macro_rules! reflexive_impl {
+ (for($($t:tt)*) $u:ty) => {
+ impl<$($t)*> CastTo<$u> for $u {
+ fn cast_to(self, _interner: <$u as HasInterner>::Interner) -> $u {
+ self
+ }
+ }
+ };
+ ($u:ty) => {
+ impl CastTo<$u> for $u {
+ fn cast_to(self, interner: <$u as HasInterner>::Interner) -> $u {
+ self
+ }
+ }
+ };
+}
+
+reflexive_impl!(for(I: Interner) TyKind<I>);
+reflexive_impl!(for(I: Interner) LifetimeData<I>);
+reflexive_impl!(for(I: Interner) ConstData<I>);
+reflexive_impl!(for(I: Interner) TraitRef<I>);
+reflexive_impl!(for(I: Interner) DomainGoal<I>);
+reflexive_impl!(for(I: Interner) Goal<I>);
+reflexive_impl!(for(I: Interner) WhereClause<I>);
+reflexive_impl!(for(I: Interner) ProgramClause<I>);
+reflexive_impl!(for(I: Interner) QuantifiedWhereClause<I>);
+reflexive_impl!(for(I: Interner) VariableKind<I>);
+reflexive_impl!(for(I: Interner) VariableKinds<I>);
+reflexive_impl!(for(I: Interner) CanonicalVarKind<I>);
+reflexive_impl!(for(I: Interner) CanonicalVarKinds<I>);
+reflexive_impl!(for(I: Interner) Constraint<I>);
+
+impl<I: Interner> CastTo<WhereClause<I>> for TraitRef<I> {
+ fn cast_to(self, _interner: I) -> WhereClause<I> {
+ WhereClause::Implemented(self)
+ }
+}
+
+impl<I: Interner> CastTo<WhereClause<I>> for AliasEq<I> {
+ fn cast_to(self, _interner: I) -> WhereClause<I> {
+ WhereClause::AliasEq(self)
+ }
+}
+
+impl<I: Interner> CastTo<WhereClause<I>> for LifetimeOutlives<I> {
+ fn cast_to(self, _interner: I) -> WhereClause<I> {
+ WhereClause::LifetimeOutlives(self)
+ }
+}
+
+impl<I: Interner> CastTo<WhereClause<I>> for TypeOutlives<I> {
+ fn cast_to(self, _interner: I) -> WhereClause<I> {
+ WhereClause::TypeOutlives(self)
+ }
+}
+
+impl<T, I> CastTo<DomainGoal<I>> for T
+where
+ T: CastTo<WhereClause<I>>,
+ I: Interner,
+{
+ fn cast_to(self, interner: I) -> DomainGoal<I> {
+ DomainGoal::Holds(self.cast(interner))
+ }
+}
+
+impl<T, I: Interner> CastTo<Goal<I>> for T
+where
+ T: CastTo<DomainGoal<I>>,
+{
+ fn cast_to(self, interner: I) -> Goal<I> {
+ GoalData::DomainGoal(self.cast(interner)).intern(interner)
+ }
+}
+
+impl<I: Interner> CastTo<DomainGoal<I>> for Normalize<I> {
+ fn cast_to(self, _interner: I) -> DomainGoal<I> {
+ DomainGoal::Normalize(self)
+ }
+}
+
+impl<I: Interner> CastTo<DomainGoal<I>> for WellFormed<I> {
+ fn cast_to(self, _interner: I) -> DomainGoal<I> {
+ DomainGoal::WellFormed(self)
+ }
+}
+
+impl<I: Interner> CastTo<DomainGoal<I>> for FromEnv<I> {
+ fn cast_to(self, _interner: I) -> DomainGoal<I> {
+ DomainGoal::FromEnv(self)
+ }
+}
+
+impl<I: Interner> CastTo<Goal<I>> for EqGoal<I> {
+ fn cast_to(self, interner: I) -> Goal<I> {
+ GoalData::EqGoal(self).intern(interner)
+ }
+}
+
+impl<I: Interner> CastTo<Goal<I>> for SubtypeGoal<I> {
+ fn cast_to(self, interner: I) -> Goal<I> {
+ GoalData::SubtypeGoal(self).intern(interner)
+ }
+}
+
+impl<I: Interner, T: HasInterner<Interner = I> + CastTo<Goal<I>>> CastTo<Goal<I>> for Binders<T> {
+ fn cast_to(self, interner: I) -> Goal<I> {
+ GoalData::Quantified(
+ QuantifierKind::ForAll,
+ self.map(|bound| bound.cast(interner)),
+ )
+ .intern(interner)
+ }
+}
+
+impl<I: Interner> CastTo<TyKind<I>> for AliasTy<I> {
+ fn cast_to(self, _interner: I) -> TyKind<I> {
+ TyKind::Alias(self)
+ }
+}
+
+impl<I: Interner> CastTo<GenericArg<I>> for Ty<I> {
+ fn cast_to(self, interner: I) -> GenericArg<I> {
+ GenericArg::new(interner, GenericArgData::Ty(self))
+ }
+}
+
+impl<I: Interner> CastTo<GenericArg<I>> for Lifetime<I> {
+ fn cast_to(self, interner: I) -> GenericArg<I> {
+ GenericArg::new(interner, GenericArgData::Lifetime(self))
+ }
+}
+
+impl<I: Interner> CastTo<GenericArg<I>> for Const<I> {
+ fn cast_to(self, interner: I) -> GenericArg<I> {
+ GenericArg::new(interner, GenericArgData::Const(self))
+ }
+}
+
+impl<I: Interner> CastTo<GenericArg<I>> for GenericArg<I> {
+ fn cast_to(self, _interner: I) -> GenericArg<I> {
+ self
+ }
+}
+
+impl<T, I> CastTo<ProgramClause<I>> for T
+where
+ T: CastTo<DomainGoal<I>>,
+ I: Interner,
+{
+ fn cast_to(self, interner: I) -> ProgramClause<I> {
+ let implication = ProgramClauseImplication {
+ consequence: self.cast(interner),
+ conditions: Goals::empty(interner),
+ constraints: Constraints::empty(interner),
+ priority: ClausePriority::High,
+ };
+
+ ProgramClauseData(Binders::empty(interner, implication.shifted_in(interner)))
+ .intern(interner)
+ }
+}
+
+impl<I, T> CastTo<ProgramClause<I>> for Binders<T>
+where
+ I: Interner,
+ T: HasInterner<Interner = I> + CastTo<DomainGoal<I>>,
+{
+ fn cast_to(self, interner: I) -> ProgramClause<I> {
+ ProgramClauseData(self.map(|bound| ProgramClauseImplication {
+ consequence: bound.cast(interner),
+ conditions: Goals::empty(interner),
+ constraints: Constraints::empty(interner),
+ priority: ClausePriority::High,
+ }))
+ .intern(interner)
+ }
+}
+
+impl<T, U> CastTo<Option<U>> for Option<T>
+where
+ T: CastTo<U>,
+ U: HasInterner,
+{
+ fn cast_to(self, interner: U::Interner) -> Option<U> {
+ self.map(|v| v.cast(interner))
+ }
+}
+
+impl<T, U, I> CastTo<InEnvironment<U>> for InEnvironment<T>
+where
+ T: HasInterner<Interner = I> + CastTo<U>,
+ U: HasInterner<Interner = I>,
+ I: Interner,
+{
+ fn cast_to(self, interner: U::Interner) -> InEnvironment<U> {
+ self.map(|v| v.cast(interner))
+ }
+}
+
+impl<T, U, E> CastTo<Result<U, E>> for Result<T, E>
+where
+ T: CastTo<U>,
+ U: HasInterner,
+{
+ fn cast_to(self, interner: U::Interner) -> Result<U, E> {
+ self.map(|v| v.cast(interner))
+ }
+}
+
+impl<T> HasInterner for Option<T>
+where
+ T: HasInterner,
+{
+ type Interner = T::Interner;
+}
+
+impl<T, E> HasInterner for Result<T, E>
+where
+ T: HasInterner,
+{
+ type Interner = T::Interner;
+}
+
+impl<T, U> CastTo<Canonical<U>> for Canonical<T>
+where
+ T: CastTo<U> + HasInterner,
+ U: HasInterner<Interner = T::Interner>,
+{
+ fn cast_to(self, interner: T::Interner) -> Canonical<U> {
+ // Subtle point: It should be ok to re-use the binders here,
+ // because `cast()` never introduces new inference variables,
+ // nor changes the "substance" of the type we are working
+ // with. It just introduces new wrapper types.
+ Canonical {
+ value: self.value.cast(interner),
+ binders: self.binders.cast(interner),
+ }
+ }
+}
+
+impl<T, U> CastTo<Vec<U>> for Vec<T>
+where
+ T: CastTo<U> + HasInterner,
+ U: HasInterner,
+{
+ fn cast_to(self, interner: U::Interner) -> Vec<U> {
+ self.into_iter().casted(interner).collect()
+ }
+}
+
+impl<T> CastTo<T> for &T
+where
+ T: Clone + HasInterner,
+{
+ fn cast_to(self, _interner: T::Interner) -> T {
+ self.clone()
+ }
+}
+
+/// An iterator that casts each element to some other type.
+pub struct Casted<IT, U: HasInterner> {
+ interner: U::Interner,
+ iterator: IT,
+ _cast: PhantomData<U>,
+}
+
+impl<IT: Iterator, U> Iterator for Casted<IT, U>
+where
+ IT::Item: CastTo<U>,
+ U: HasInterner,
+{
+ type Item = U;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iterator.next().map(|item| item.cast_to(self.interner))
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iterator.size_hint()
+ }
+}
+
+/// An iterator adapter that casts each element we are iterating over
+/// to some other type.
+pub trait Caster: Iterator + Sized {
+ /// Cast each element in this iterator.
+ fn casted<U>(self, interner: U::Interner) -> Casted<Self, U>
+ where
+ Self::Item: CastTo<U>,
+ U: HasInterner,
+ {
+ Casted {
+ interner,
+ iterator: self,
+ _cast: PhantomData,
+ }
+ }
+}
+
+impl<I> Caster for I where I: Iterator {}
diff --git a/vendor/chalk-ir/src/could_match.rs b/vendor/chalk-ir/src/could_match.rs
new file mode 100644
index 000000000..9f94ff47a
--- /dev/null
+++ b/vendor/chalk-ir/src/could_match.rs
@@ -0,0 +1,213 @@
+//! Fast matching check for zippable values.
+
+use crate::interner::HasInterner;
+use crate::zip::{Zip, Zipper};
+use crate::*;
+
+/// A fast check to see whether two things could ever possibly match.
+pub trait CouldMatch<T: ?Sized + HasInterner> {
+ /// Checks whether `self` and `other` could possibly match.
+ fn could_match(
+ &self,
+ interner: T::Interner,
+ db: &dyn UnificationDatabase<T::Interner>,
+ other: &T,
+ ) -> bool;
+}
+
+#[allow(unreachable_code, unused_variables)]
+impl<T, I> CouldMatch<T> for T
+where
+ T: Zip<I> + ?Sized + HasInterner<Interner = I>,
+ I: Interner,
+{
+ fn could_match(&self, interner: I, db: &dyn UnificationDatabase<I>, other: &T) -> bool {
+ return Zip::zip_with(
+ &mut MatchZipper { interner, db },
+ Variance::Invariant,
+ self,
+ other,
+ )
+ .is_ok();
+
+ struct MatchZipper<'i, I> {
+ interner: I,
+ db: &'i dyn UnificationDatabase<I>,
+ }
+
+ impl<'i, I: Interner> Zipper<I> for MatchZipper<'i, I> {
+ fn zip_tys(&mut self, variance: Variance, a: &Ty<I>, b: &Ty<I>) -> Fallible<()> {
+ let interner = self.interner;
+ let matches = |a: &Substitution<I>, b: &Substitution<I>| {
+ a.iter(interner)
+ .zip(b.iter(interner))
+ .all(|(p_a, p_b)| p_a.could_match(interner, self.db, p_b))
+ };
+ let could_match = match (a.kind(interner), b.kind(interner)) {
+ (TyKind::Adt(id_a, substitution_a), TyKind::Adt(id_b, substitution_b)) => {
+ id_a == id_b
+ && self
+ .zip_substs(
+ variance,
+ Some(self.unification_database().adt_variance(*id_a)),
+ substitution_a.as_slice(interner),
+ substitution_b.as_slice(interner),
+ )
+ .is_ok()
+ }
+ (
+ TyKind::AssociatedType(assoc_ty_a, substitution_a),
+ TyKind::AssociatedType(assoc_ty_b, substitution_b),
+ ) => assoc_ty_a == assoc_ty_b && matches(substitution_a, substitution_b),
+ (TyKind::Scalar(scalar_a), TyKind::Scalar(scalar_b)) => scalar_a == scalar_b,
+ (TyKind::Str, TyKind::Str) => true,
+ (
+ TyKind::Tuple(arity_a, substitution_a),
+ TyKind::Tuple(arity_b, substitution_b),
+ ) => arity_a == arity_b && matches(substitution_a, substitution_b),
+ (
+ TyKind::OpaqueType(opaque_ty_a, substitution_a),
+ TyKind::OpaqueType(opaque_ty_b, substitution_b),
+ ) => opaque_ty_a == opaque_ty_b && matches(substitution_a, substitution_b),
+ (TyKind::Slice(ty_a), TyKind::Slice(ty_b)) => {
+ ty_a.could_match(interner, self.db, ty_b)
+ }
+ (
+ TyKind::FnDef(fn_def_a, substitution_a),
+ TyKind::FnDef(fn_def_b, substitution_b),
+ ) => {
+ fn_def_a == fn_def_b
+ && self
+ .zip_substs(
+ variance,
+ Some(self.unification_database().fn_def_variance(*fn_def_a)),
+ substitution_a.as_slice(interner),
+ substitution_b.as_slice(interner),
+ )
+ .is_ok()
+ }
+ (
+ TyKind::Ref(mutability_a, lifetime_a, ty_a),
+ TyKind::Ref(mutability_b, lifetime_b, ty_b),
+ ) => {
+ mutability_a == mutability_b
+ && lifetime_a.could_match(interner, self.db, lifetime_b)
+ && ty_a.could_match(interner, self.db, ty_b)
+ }
+ (TyKind::Raw(mutability_a, ty_a), TyKind::Raw(mutability_b, ty_b)) => {
+ mutability_a == mutability_b && ty_a.could_match(interner, self.db, ty_b)
+ }
+ (TyKind::Never, TyKind::Never) => true,
+ (TyKind::Array(ty_a, const_a), TyKind::Array(ty_b, const_b)) => {
+ ty_a.could_match(interner, self.db, ty_b)
+ && const_a.could_match(interner, self.db, const_b)
+ }
+ (
+ TyKind::Closure(id_a, substitution_a),
+ TyKind::Closure(id_b, substitution_b),
+ ) => id_a == id_b && matches(substitution_a, substitution_b),
+ (
+ TyKind::Generator(generator_a, substitution_a),
+ TyKind::Generator(generator_b, substitution_b),
+ ) => {
+ generator_a == generator_b
+ && self
+ .zip_substs(
+ variance,
+ None,
+ substitution_a.as_slice(interner),
+ substitution_b.as_slice(interner),
+ )
+ .is_ok()
+ }
+ (
+ TyKind::GeneratorWitness(generator_a, substitution_a),
+ TyKind::GeneratorWitness(generator_b, substitution_b),
+ ) => {
+ generator_a == generator_b
+ && self
+ .zip_substs(
+ variance,
+ None,
+ substitution_a.as_slice(interner),
+ substitution_b.as_slice(interner),
+ )
+ .is_ok()
+ }
+ (TyKind::Foreign(foreign_ty_a), TyKind::Foreign(foreign_ty_b)) => {
+ foreign_ty_a == foreign_ty_b
+ }
+ (TyKind::Error, TyKind::Error) => true,
+
+ _ => true,
+ };
+
+ if could_match {
+ Ok(())
+ } else {
+ Err(NoSolution)
+ }
+ }
+
+ fn zip_lifetimes(
+ &mut self,
+ variance: Variance,
+ _: &Lifetime<I>,
+ _: &Lifetime<I>,
+ ) -> Fallible<()> {
+ Ok(())
+ }
+
+ fn zip_consts(
+ &mut self,
+ variance: Variance,
+ _: &Const<I>,
+ _: &Const<I>,
+ ) -> Fallible<()> {
+ Ok(())
+ }
+
+ fn zip_binders<T>(
+ &mut self,
+ variance: Variance,
+ a: &Binders<T>,
+ b: &Binders<T>,
+ ) -> Fallible<()>
+ where
+ T: HasInterner + Zip<I>,
+ {
+ Zip::zip_with(self, variance, &a.value, &b.value)
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+
+ fn unification_database(&self) -> &dyn UnificationDatabase<I> {
+ self.db
+ }
+ }
+ }
+}
+
+impl<I: Interner> CouldMatch<DomainGoal<I>> for ProgramClauseData<I> {
+ fn could_match(
+ &self,
+ interner: I,
+ db: &dyn UnificationDatabase<I>,
+ other: &DomainGoal<I>,
+ ) -> bool {
+ self.0.value.consequence.could_match(interner, db, other)
+ }
+}
+
+impl<I: Interner> CouldMatch<DomainGoal<I>> for ProgramClause<I> {
+ fn could_match(
+ &self,
+ interner: I,
+ db: &dyn UnificationDatabase<I>,
+ other: &DomainGoal<I>,
+ ) -> bool {
+ self.data(interner).could_match(interner, db, other)
+ }
+}
diff --git a/vendor/chalk-ir/src/debug.rs b/vendor/chalk-ir/src/debug.rs
new file mode 100644
index 000000000..76d66edf5
--- /dev/null
+++ b/vendor/chalk-ir/src/debug.rs
@@ -0,0 +1,1016 @@
+//! Debug impls for types.
+
+use std::fmt::{self, Debug, Display, Error, Formatter};
+
+use super::*;
+
+/// Wrapper to allow forwarding to `Display::fmt`, `Debug::fmt`, etc.
+pub struct Fmt<F>(pub F)
+where
+ F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result;
+
+impl<F> fmt::Display for Fmt<F>
+where
+ F: Fn(&mut fmt::Formatter<'_>) -> fmt::Result,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ (self.0)(f)
+ }
+}
+
+impl<I: Interner> Debug for TraitId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_trait_id(*self, fmt).unwrap_or_else(|| write!(fmt, "TraitId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for AdtId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_adt_id(*self, fmt).unwrap_or_else(|| write!(fmt, "AdtId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for AssocTypeId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_assoc_type_id(*self, fmt)
+ .unwrap_or_else(|| write!(fmt, "AssocTypeId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for FnDefId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> std::fmt::Result {
+ I::debug_fn_def_id(*self, fmt).unwrap_or_else(|| write!(fmt, "FnDefId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for ClosureId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> std::fmt::Result {
+ I::debug_closure_id(*self, fmt).unwrap_or_else(|| write!(fmt, "ClosureId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for GeneratorId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> std::fmt::Result {
+ I::debug_generator_id(*self, fmt)
+ .unwrap_or_else(|| write!(fmt, "GeneratorId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for ForeignDefId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> std::fmt::Result {
+ I::debug_foreign_def_id(*self, fmt)
+ .unwrap_or_else(|| write!(fmt, "ForeignDefId({:?})", self.0))
+ }
+}
+
+impl<I: Interner> Debug for Ty<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_ty(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for Lifetime<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_lifetime(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for Const<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_const(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for ConcreteConst<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "{:?}", self.interned)
+ }
+}
+
+impl<I: Interner> Debug for GenericArg<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_generic_arg(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for Goal<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_goal(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for Goals<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_goals(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for ProgramClauseImplication<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_program_clause_implication(self, fmt)
+ .unwrap_or_else(|| write!(fmt, "ProgramClauseImplication(?)"))
+ }
+}
+
+impl<I: Interner> Debug for ProgramClause<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_program_clause(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for ProgramClauses<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_program_clauses(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for Constraints<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_constraints(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for SeparatorTraitRef<'_, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_separator_trait_ref(self, fmt)
+ .unwrap_or_else(|| write!(fmt, "SeparatorTraitRef(?)"))
+ }
+}
+
+impl<I: Interner> Debug for AliasTy<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_alias(self, fmt).unwrap_or_else(|| write!(fmt, "AliasTy(?)"))
+ }
+}
+
+impl<I: Interner> Debug for QuantifiedWhereClauses<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_quantified_where_clauses(self, fmt)
+ .unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for ProjectionTy<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_projection_ty(self, fmt).unwrap_or_else(|| {
+ unimplemented!("cannot format ProjectionTy without setting Program in tls")
+ })
+ }
+}
+
+impl<I: Interner> Debug for OpaqueTy<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_opaque_ty(self, fmt).unwrap_or_else(|| {
+ unimplemented!("cannot format OpaqueTy without setting Program in tls")
+ })
+ }
+}
+
+impl<I: Interner> Display for Substitution<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_substitution(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<I: Interner> Debug for OpaqueTyId<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_opaque_ty_id(*self, fmt).unwrap_or_else(|| write!(fmt, "OpaqueTyId({:?})", self.0))
+ }
+}
+
+impl Display for UniverseIndex {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "U{}", self.counter)
+ }
+}
+
+impl Debug for UniverseIndex {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "U{}", self.counter)
+ }
+}
+
+impl<I: Interner> Debug for TyData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ self.kind.fmt(fmt)
+ }
+}
+
+impl<I: Interner> Debug for TyKind<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ TyKind::BoundVar(db) => write!(fmt, "{:?}", db),
+ TyKind::Dyn(clauses) => write!(fmt, "{:?}", clauses),
+ TyKind::InferenceVar(var, TyVariableKind::General) => write!(fmt, "{:?}", var),
+ TyKind::InferenceVar(var, TyVariableKind::Integer) => write!(fmt, "{:?}i", var),
+ TyKind::InferenceVar(var, TyVariableKind::Float) => write!(fmt, "{:?}f", var),
+ TyKind::Alias(alias) => write!(fmt, "{:?}", alias),
+ TyKind::Placeholder(index) => write!(fmt, "{:?}", index),
+ TyKind::Function(function) => write!(fmt, "{:?}", function),
+ TyKind::Adt(id, substitution) => write!(fmt, "{:?}<{:?}>", id, substitution),
+ TyKind::AssociatedType(assoc_ty, substitution) => {
+ write!(fmt, "{:?}<{:?}>", assoc_ty, substitution)
+ }
+ TyKind::Scalar(scalar) => write!(fmt, "{:?}", scalar),
+ TyKind::Str => write!(fmt, "Str"),
+ TyKind::Tuple(arity, substitution) => write!(fmt, "{:?}<{:?}>", arity, substitution),
+ TyKind::OpaqueType(opaque_ty, substitution) => {
+ write!(fmt, "!{:?}<{:?}>", opaque_ty, substitution)
+ }
+ TyKind::Slice(substitution) => write!(fmt, "{{slice}}<{:?}>", substitution),
+ TyKind::FnDef(fn_def, substitution) => write!(fmt, "{:?}<{:?}>", fn_def, substitution),
+ TyKind::Ref(mutability, lifetime, ty) => match mutability {
+ Mutability::Mut => write!(fmt, "(&{:?} mut {:?})", lifetime, ty),
+ Mutability::Not => write!(fmt, "(&{:?} {:?})", lifetime, ty),
+ },
+ TyKind::Raw(mutability, ty) => match mutability {
+ Mutability::Mut => write!(fmt, "(*mut {:?})", ty),
+ Mutability::Not => write!(fmt, "(*const {:?})", ty),
+ },
+ TyKind::Never => write!(fmt, "Never"),
+ TyKind::Array(ty, const_) => write!(fmt, "[{:?}; {:?}]", ty, const_),
+ TyKind::Closure(id, substitution) => {
+ write!(fmt, "{{closure:{:?}}}<{:?}>", id, substitution)
+ }
+ TyKind::Generator(generator, substitution) => {
+ write!(fmt, "{:?}<{:?}>", generator, substitution)
+ }
+ TyKind::GeneratorWitness(witness, substitution) => {
+ write!(fmt, "{:?}<{:?}>", witness, substitution)
+ }
+ TyKind::Foreign(foreign_ty) => write!(fmt, "{:?}", foreign_ty),
+ TyKind::Error => write!(fmt, "{{error}}"),
+ }
+ }
+}
+
+impl Debug for BoundVar {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let BoundVar { debruijn, index } = self;
+ write!(fmt, "{:?}.{:?}", debruijn, index)
+ }
+}
+
+impl Debug for DebruijnIndex {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let DebruijnIndex { depth } = self;
+ write!(fmt, "^{}", depth)
+ }
+}
+
+impl<I: Interner> Debug for DynTy<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let DynTy { bounds, lifetime } = self;
+ write!(fmt, "dyn {:?} + {:?}", bounds, lifetime)
+ }
+}
+
+impl Debug for InferenceVar {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "?{}", self.index)
+ }
+}
+
+impl<I: Interner> Debug for FnSubst<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "{:?}", self.0)
+ }
+}
+
+impl<I: Interner> Debug for FnPointer<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ // FIXME -- we should introduce some names or something here
+ let FnPointer {
+ num_binders,
+ substitution,
+ sig,
+ } = self;
+ write!(
+ fmt,
+ "{}{:?} for<{}> {:?}",
+ match sig.safety {
+ Safety::Unsafe => "unsafe ",
+ Safety::Safe => "",
+ },
+ sig.abi,
+ num_binders,
+ substitution
+ )
+ }
+}
+
+impl<I: Interner> Debug for LifetimeData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ LifetimeData::BoundVar(db) => write!(fmt, "'{:?}", db),
+ LifetimeData::InferenceVar(var) => write!(fmt, "'{:?}", var),
+ LifetimeData::Placeholder(index) => write!(fmt, "'{:?}", index),
+ LifetimeData::Static => write!(fmt, "'static"),
+ LifetimeData::Erased => write!(fmt, "'<erased>"),
+ LifetimeData::Phantom(..) => unreachable!(),
+ }
+ }
+}
+
+impl<I: Interner> VariableKinds<I> {
+ fn debug(&self) -> VariableKindsDebug<'_, I> {
+ VariableKindsDebug(self)
+ }
+
+ /// Helper method for debugging variable kinds.
+ pub fn inner_debug(&self, interner: I) -> VariableKindsInnerDebug<'_, I> {
+ VariableKindsInnerDebug {
+ variable_kinds: self,
+ interner,
+ }
+ }
+}
+
+struct VariableKindsDebug<'a, I: Interner>(&'a VariableKinds<I>);
+
+impl<'a, I: Interner> Debug for VariableKindsDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_variable_kinds_with_angles(self.0, fmt)
+ .unwrap_or_else(|| write!(fmt, "{:?}", self.0.interned))
+ }
+}
+
+/// Helper struct for showing debug output for `VariableKinds`.
+pub struct VariableKindsInnerDebug<'a, I: Interner> {
+ variable_kinds: &'a VariableKinds<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for VariableKindsInnerDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ // NB: We print variable kinds as a list delimited by `<>`,
+ // like `<K1, K2, ..>`. This is because variable kind lists
+ // are always associated with binders like `forall<type> {
+ // ... }`.
+ write!(fmt, "<")?;
+ for (index, binder) in self.variable_kinds.iter(self.interner).enumerate() {
+ if index > 0 {
+ write!(fmt, ", ")?;
+ }
+ match binder {
+ VariableKind::Ty(TyVariableKind::General) => write!(fmt, "type")?,
+ VariableKind::Ty(TyVariableKind::Integer) => write!(fmt, "integer type")?,
+ VariableKind::Ty(TyVariableKind::Float) => write!(fmt, "float type")?,
+ VariableKind::Lifetime => write!(fmt, "lifetime")?,
+ VariableKind::Const(ty) => write!(fmt, "const: {:?}", ty)?,
+ }
+ }
+ write!(fmt, ">")
+ }
+}
+
+impl<I: Interner> Debug for ConstData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match &self.value {
+ ConstValue::BoundVar(db) => write!(fmt, "{:?}", db),
+ ConstValue::InferenceVar(var) => write!(fmt, "{:?}", var),
+ ConstValue::Placeholder(index) => write!(fmt, "{:?}", index),
+ ConstValue::Concrete(evaluated) => write!(fmt, "{:?}", evaluated),
+ }
+ }
+}
+
+impl<I: Interner> Debug for GoalData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ GoalData::Quantified(qkind, ref subgoal) => write!(
+ fmt,
+ "{:?}{:?} {{ {:?} }}",
+ qkind,
+ subgoal.binders.debug(),
+ subgoal.value
+ ),
+ GoalData::Implies(ref wc, ref g) => write!(fmt, "if ({:?}) {{ {:?} }}", wc, g),
+ GoalData::All(ref goals) => write!(fmt, "all{:?}", goals),
+ GoalData::Not(ref g) => write!(fmt, "not {{ {:?} }}", g),
+ GoalData::EqGoal(ref wc) => write!(fmt, "{:?}", wc),
+ GoalData::SubtypeGoal(ref wc) => write!(fmt, "{:?}", wc),
+ GoalData::DomainGoal(ref wc) => write!(fmt, "{:?}", wc),
+ GoalData::CannotProve => write!(fmt, r"¯\_(ツ)_/¯"),
+ }
+ }
+}
+
+/// Helper struct for showing debug output for `Goals`.
+pub struct GoalsDebug<'a, I: Interner> {
+ goals: &'a Goals<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for GoalsDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "(")?;
+ for (goal, index) in self.goals.iter(self.interner).zip(0..) {
+ if index > 0 {
+ write!(fmt, ", ")?;
+ }
+ write!(fmt, "{:?}", goal)?;
+ }
+ write!(fmt, ")")?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Goals<I> {
+ /// Show debug output for `Goals`.
+ pub fn debug(&self, interner: I) -> GoalsDebug<'_, I> {
+ GoalsDebug {
+ goals: self,
+ interner,
+ }
+ }
+}
+
+/// Helper struct for showing debug output for `GenericArgData`.
+pub struct GenericArgDataInnerDebug<'a, I: Interner>(&'a GenericArgData<I>);
+
+impl<'a, I: Interner> Debug for GenericArgDataInnerDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self.0 {
+ GenericArgData::Ty(n) => write!(fmt, "{:?}", n),
+ GenericArgData::Lifetime(n) => write!(fmt, "{:?}", n),
+ GenericArgData::Const(n) => write!(fmt, "{:?}", n),
+ }
+ }
+}
+
+impl<I: Interner> GenericArgData<I> {
+ /// Helper method for debugging `GenericArgData`.
+ pub fn inner_debug(&self) -> GenericArgDataInnerDebug<'_, I> {
+ GenericArgDataInnerDebug(self)
+ }
+}
+
+/// Helper struct for showing debug output for program clause implications.
+pub struct ProgramClauseImplicationDebug<'a, I: Interner> {
+ pci: &'a ProgramClauseImplication<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for ProgramClauseImplicationDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let ProgramClauseImplicationDebug { pci, interner } = self;
+ write!(fmt, "{:?}", pci.consequence)?;
+
+ let conditions = pci.conditions.as_slice(*interner);
+
+ let conds = conditions.len();
+ if conds == 0 {
+ return Ok(());
+ }
+
+ write!(fmt, " :- ")?;
+ for cond in &conditions[..conds - 1] {
+ write!(fmt, "{:?}, ", cond)?;
+ }
+ write!(fmt, "{:?}", conditions[conds - 1])
+ }
+}
+
+impl<I: Interner> ProgramClauseImplication<I> {
+ /// Show debug output for the program clause implication.
+ pub fn debug(&self, interner: I) -> ProgramClauseImplicationDebug<'_, I> {
+ ProgramClauseImplicationDebug {
+ pci: self,
+ interner,
+ }
+ }
+}
+
+/// Helper struct for showing debug output for application types.
+pub struct TyKindDebug<'a, I: Interner> {
+ ty: &'a TyKind<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for TyKindDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let interner = self.interner;
+ match self.ty {
+ TyKind::BoundVar(db) => write!(fmt, "{:?}", db),
+ TyKind::Dyn(clauses) => write!(fmt, "{:?}", clauses),
+ TyKind::InferenceVar(var, TyVariableKind::General) => write!(fmt, "{:?}", var),
+ TyKind::InferenceVar(var, TyVariableKind::Integer) => write!(fmt, "{:?}i", var),
+ TyKind::InferenceVar(var, TyVariableKind::Float) => write!(fmt, "{:?}f", var),
+ TyKind::Alias(alias) => write!(fmt, "{:?}", alias),
+ TyKind::Placeholder(index) => write!(fmt, "{:?}", index),
+ TyKind::Function(function) => write!(fmt, "{:?}", function),
+ TyKind::Adt(id, substitution) => {
+ write!(fmt, "{:?}{:?}", id, substitution.with_angle(interner))
+ }
+ TyKind::AssociatedType(assoc_ty, substitution) => {
+ write!(fmt, "{:?}{:?}", assoc_ty, substitution.with_angle(interner))
+ }
+ TyKind::Scalar(scalar) => write!(fmt, "{:?}", scalar),
+ TyKind::Str => write!(fmt, "Str"),
+ TyKind::Tuple(arity, substitution) => {
+ write!(fmt, "{:?}{:?}", arity, substitution.with_angle(interner))
+ }
+ TyKind::OpaqueType(opaque_ty, substitution) => write!(
+ fmt,
+ "!{:?}{:?}",
+ opaque_ty,
+ substitution.with_angle(interner)
+ ),
+ TyKind::Slice(ty) => write!(fmt, "[{:?}]", ty),
+ TyKind::FnDef(fn_def, substitution) => {
+ write!(fmt, "{:?}{:?}", fn_def, substitution.with_angle(interner))
+ }
+ TyKind::Ref(mutability, lifetime, ty) => match mutability {
+ Mutability::Mut => write!(fmt, "(&{:?} mut {:?})", lifetime, ty),
+ Mutability::Not => write!(fmt, "(&{:?} {:?})", lifetime, ty),
+ },
+ TyKind::Raw(mutability, ty) => match mutability {
+ Mutability::Mut => write!(fmt, "(*mut {:?})", ty),
+ Mutability::Not => write!(fmt, "(*const {:?})", ty),
+ },
+ TyKind::Never => write!(fmt, "Never"),
+ TyKind::Array(ty, const_) => write!(fmt, "[{:?}; {:?}]", ty, const_),
+ TyKind::Closure(id, substitution) => write!(
+ fmt,
+ "{{closure:{:?}}}{:?}",
+ id,
+ substitution.with_angle(interner)
+ ),
+ TyKind::Generator(generator, substitution) => write!(
+ fmt,
+ "{:?}{:?}",
+ generator,
+ substitution.with_angle(interner)
+ ),
+ TyKind::GeneratorWitness(witness, substitution) => {
+ write!(fmt, "{:?}{:?}", witness, substitution.with_angle(interner))
+ }
+ TyKind::Foreign(foreign_ty) => write!(fmt, "{:?}", foreign_ty,),
+ TyKind::Error => write!(fmt, "{{error}}"),
+ }
+ }
+}
+
+impl<I: Interner> TyKind<I> {
+ /// Show debug output for the application type.
+ pub fn debug(&self, interner: I) -> TyKindDebug<'_, I> {
+ TyKindDebug { ty: self, interner }
+ }
+}
+
+/// Helper struct for showing debug output for substitutions.
+pub struct SubstitutionDebug<'a, I: Interner> {
+ substitution: &'a Substitution<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for SubstitutionDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let SubstitutionDebug {
+ substitution,
+ interner,
+ } = self;
+ let mut first = true;
+
+ write!(fmt, "[")?;
+
+ for (index, value) in substitution.iter(*interner).enumerate() {
+ if first {
+ first = false;
+ } else {
+ write!(fmt, ", ")?;
+ }
+
+ write!(fmt, "?{} := {:?}", index, value)?;
+ }
+
+ write!(fmt, "]")?;
+
+ Ok(())
+ }
+}
+
+impl<I: Interner> Substitution<I> {
+ /// Show debug output for the substitution.
+ pub fn debug(&self, interner: I) -> SubstitutionDebug<'_, I> {
+ SubstitutionDebug {
+ substitution: self,
+ interner,
+ }
+ }
+}
+
+impl Debug for PlaceholderIndex {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let PlaceholderIndex { ui, idx } = self;
+ write!(fmt, "!{}_{}", ui.counter, idx)
+ }
+}
+
+impl<I: Interner> TraitRef<I> {
+ /// Returns a "Debuggable" type that prints like `P0 as Trait<P1..>`.
+ pub fn with_as(&self) -> impl std::fmt::Debug + '_ {
+ SeparatorTraitRef {
+ trait_ref: self,
+ separator: " as ",
+ }
+ }
+
+ /// Returns a "Debuggable" type that prints like `P0: Trait<P1..>`.
+ pub fn with_colon(&self) -> impl std::fmt::Debug + '_ {
+ SeparatorTraitRef {
+ trait_ref: self,
+ separator: ": ",
+ }
+ }
+}
+
+impl<I: Interner> Debug for TraitRef<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ Debug::fmt(&self.with_as(), fmt)
+ }
+}
+
+/// Trait ref with associated separator used for debug output.
+pub struct SeparatorTraitRef<'me, I: Interner> {
+ /// The `TraitRef` itself.
+ pub trait_ref: &'me TraitRef<I>,
+
+ /// The separator used for displaying the `TraitRef`.
+ pub separator: &'me str,
+}
+
+/// Helper struct for showing debug output for the `SeperatorTraitRef`.
+pub struct SeparatorTraitRefDebug<'a, 'me, I: Interner> {
+ separator_trait_ref: &'a SeparatorTraitRef<'me, I>,
+ interner: I,
+}
+
+impl<'a, 'me, I: Interner> Debug for SeparatorTraitRefDebug<'a, 'me, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let SeparatorTraitRefDebug {
+ separator_trait_ref,
+ interner,
+ } = self;
+ let parameters = separator_trait_ref
+ .trait_ref
+ .substitution
+ .as_slice(*interner);
+ write!(
+ fmt,
+ "{:?}{}{:?}{:?}",
+ parameters[0],
+ separator_trait_ref.separator,
+ separator_trait_ref.trait_ref.trait_id,
+ Angle(&parameters[1..])
+ )
+ }
+}
+
+impl<'me, I: Interner> SeparatorTraitRef<'me, I> {
+ /// Show debug output for the `SeperatorTraitRef`.
+ pub fn debug<'a>(&'a self, interner: I) -> SeparatorTraitRefDebug<'a, 'me, I> {
+ SeparatorTraitRefDebug {
+ separator_trait_ref: self,
+ interner,
+ }
+ }
+}
+
+impl<I: Interner> Debug for LifetimeOutlives<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "{:?}: {:?}", self.a, self.b)
+ }
+}
+
+impl<I: Interner> Debug for TypeOutlives<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "{:?}: {:?}", self.ty, self.lifetime)
+ }
+}
+
+/// Helper struct for showing debug output for projection types.
+pub struct ProjectionTyDebug<'a, I: Interner> {
+ projection_ty: &'a ProjectionTy<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for ProjectionTyDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let ProjectionTyDebug {
+ projection_ty,
+ interner,
+ } = self;
+ write!(
+ fmt,
+ "({:?}){:?}",
+ projection_ty.associated_ty_id,
+ projection_ty.substitution.with_angle(*interner)
+ )
+ }
+}
+
+impl<I: Interner> ProjectionTy<I> {
+ /// Show debug output for the projection type.
+ pub fn debug(&self, interner: I) -> ProjectionTyDebug<'_, I> {
+ ProjectionTyDebug {
+ projection_ty: self,
+ interner,
+ }
+ }
+}
+
+/// Helper struct for showing debug output for opaque types.
+pub struct OpaqueTyDebug<'a, I: Interner> {
+ opaque_ty: &'a OpaqueTy<I>,
+ interner: I,
+}
+
+impl<'a, I: Interner> Debug for OpaqueTyDebug<'a, I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let OpaqueTyDebug {
+ opaque_ty,
+ interner,
+ } = self;
+ write!(
+ fmt,
+ "{:?}{:?}",
+ opaque_ty.opaque_ty_id,
+ opaque_ty.substitution.with_angle(*interner)
+ )
+ }
+}
+
+impl<I: Interner> OpaqueTy<I> {
+ /// Show debug output for the opaque type.
+ pub fn debug(&self, interner: I) -> OpaqueTyDebug<'_, I> {
+ OpaqueTyDebug {
+ opaque_ty: self,
+ interner,
+ }
+ }
+}
+
+/// Wraps debug output in angle brackets (`<>`).
+pub struct Angle<'a, T>(pub &'a [T]);
+
+impl<'a, T: Debug> Debug for Angle<'a, T> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ if !self.0.is_empty() {
+ write!(fmt, "<")?;
+ for (index, elem) in self.0.iter().enumerate() {
+ if index > 0 {
+ write!(fmt, ", {:?}", elem)?;
+ } else {
+ write!(fmt, "{:?}", elem)?;
+ }
+ }
+ write!(fmt, ">")?;
+ }
+ Ok(())
+ }
+}
+
+impl<I: Interner> Debug for Normalize<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "Normalize({:?} -> {:?})", self.alias, self.ty)
+ }
+}
+
+impl<I: Interner> Debug for AliasEq<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "AliasEq({:?} = {:?})", self.alias, self.ty)
+ }
+}
+
+impl<I: Interner> Debug for WhereClause<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ WhereClause::Implemented(tr) => write!(fmt, "Implemented({:?})", tr.with_colon()),
+ WhereClause::AliasEq(a) => write!(fmt, "{:?}", a),
+ WhereClause::LifetimeOutlives(l_o) => write!(fmt, "{:?}", l_o),
+ WhereClause::TypeOutlives(t_o) => write!(fmt, "{:?}", t_o),
+ }
+ }
+}
+
+impl<I: Interner> Debug for FromEnv<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ FromEnv::Trait(t) => write!(fmt, "FromEnv({:?})", t.with_colon()),
+ FromEnv::Ty(t) => write!(fmt, "FromEnv({:?})", t),
+ }
+ }
+}
+
+impl<I: Interner> Debug for WellFormed<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ WellFormed::Trait(t) => write!(fmt, "WellFormed({:?})", t.with_colon()),
+ WellFormed::Ty(t) => write!(fmt, "WellFormed({:?})", t),
+ }
+ }
+}
+
+impl<I: Interner> Debug for DomainGoal<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ DomainGoal::Holds(n) => write!(fmt, "{:?}", n),
+ DomainGoal::WellFormed(n) => write!(fmt, "{:?}", n),
+ DomainGoal::FromEnv(n) => write!(fmt, "{:?}", n),
+ DomainGoal::Normalize(n) => write!(fmt, "{:?}", n),
+ DomainGoal::IsLocal(n) => write!(fmt, "IsLocal({:?})", n),
+ DomainGoal::IsUpstream(n) => write!(fmt, "IsUpstream({:?})", n),
+ DomainGoal::IsFullyVisible(n) => write!(fmt, "IsFullyVisible({:?})", n),
+ DomainGoal::LocalImplAllowed(tr) => {
+ write!(fmt, "LocalImplAllowed({:?})", tr.with_colon(),)
+ }
+ DomainGoal::Compatible => write!(fmt, "Compatible"),
+ DomainGoal::DownstreamType(n) => write!(fmt, "DownstreamType({:?})", n),
+ DomainGoal::Reveal => write!(fmt, "Reveal"),
+ DomainGoal::ObjectSafe(n) => write!(fmt, "ObjectSafe({:?})", n),
+ }
+ }
+}
+
+impl<I: Interner> Debug for EqGoal<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "({:?} = {:?})", self.a, self.b)
+ }
+}
+
+impl<I: Interner> Debug for SubtypeGoal<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "({:?} <: {:?})", self.a, self.b)
+ }
+}
+
+impl<T: HasInterner + Debug> Debug for Binders<T> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let Binders {
+ ref binders,
+ ref value,
+ } = *self;
+ write!(fmt, "for{:?} ", binders.debug())?;
+ Debug::fmt(value, fmt)
+ }
+}
+
+impl<I: Interner> Debug for ProgramClauseData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "{:?}", self.0)
+ }
+}
+
+impl<I: Interner> Debug for Environment<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ write!(fmt, "Env({:?})", self.clauses)
+ }
+}
+
+impl<I: Interner> Debug for CanonicalVarKinds<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_canonical_var_kinds(self, fmt)
+ .unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
+
+impl<T: HasInterner + Display> Canonical<T> {
+ /// Display the canonicalized item.
+ pub fn display(&self, interner: T::Interner) -> CanonicalDisplay<'_, T> {
+ CanonicalDisplay {
+ canonical: self,
+ interner,
+ }
+ }
+}
+
+/// Helper struct for displaying canonicalized items.
+pub struct CanonicalDisplay<'a, T: HasInterner> {
+ canonical: &'a Canonical<T>,
+ interner: T::Interner,
+}
+
+impl<'a, T: HasInterner + Display> Display for CanonicalDisplay<'a, T> {
+ fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+ let Canonical { binders, value } = self.canonical;
+ let interner = self.interner;
+ let binders = binders.as_slice(interner);
+ if binders.is_empty() {
+ // Ordinarily, we try to print all binder levels, if they
+ // are empty, but we can skip in this *particular* case
+ // because we know that `Canonical` terms are never
+ // supposed to contain free variables. In other words,
+ // all "bound variables" that appear inside the canonical
+ // value must reference values that appear in `binders`.
+ write!(f, "{}", value)?;
+ } else {
+ write!(f, "for<")?;
+
+ for (i, pk) in binders.iter().enumerate() {
+ if i > 0 {
+ write!(f, ",")?;
+ }
+ write!(f, "?{}", pk.skip_kind())?;
+ }
+
+ write!(f, "> {{ {} }}", value)?;
+ }
+
+ Ok(())
+ }
+}
+
+impl<I: Interner> Debug for GenericArgData<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ GenericArgData::Ty(t) => write!(fmt, "Ty({:?})", t),
+ GenericArgData::Lifetime(l) => write!(fmt, "Lifetime({:?})", l),
+ GenericArgData::Const(c) => write!(fmt, "Const({:?})", c),
+ }
+ }
+}
+
+impl<I: Interner> Debug for VariableKind<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ VariableKind::Ty(TyVariableKind::General) => write!(fmt, "type"),
+ VariableKind::Ty(TyVariableKind::Integer) => write!(fmt, "integer type"),
+ VariableKind::Ty(TyVariableKind::Float) => write!(fmt, "float type"),
+ VariableKind::Lifetime => write!(fmt, "lifetime"),
+ VariableKind::Const(ty) => write!(fmt, "const: {:?}", ty),
+ }
+ }
+}
+
+impl<I: Interner, T: Debug> Debug for WithKind<I, T> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ let value = self.skip_kind();
+ match &self.kind {
+ VariableKind::Ty(TyVariableKind::General) => write!(fmt, "{:?} with kind type", value),
+ VariableKind::Ty(TyVariableKind::Integer) => {
+ write!(fmt, "{:?} with kind integer type", value)
+ }
+ VariableKind::Ty(TyVariableKind::Float) => {
+ write!(fmt, "{:?} with kind float type", value)
+ }
+ VariableKind::Lifetime => write!(fmt, "{:?} with kind lifetime", value),
+ VariableKind::Const(ty) => write!(fmt, "{:?} with kind {:?}", value, ty),
+ }
+ }
+}
+
+impl<I: Interner> Debug for Constraint<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ match self {
+ Constraint::LifetimeOutlives(a, b) => write!(fmt, "{:?}: {:?}", a, b),
+ Constraint::TypeOutlives(ty, lifetime) => write!(fmt, "{:?}: {:?}", ty, lifetime),
+ }
+ }
+}
+
+impl<I: Interner> Display for ConstrainedSubst<I> {
+ #[rustfmt::skip]
+ fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
+ let ConstrainedSubst { subst, constraints } = self;
+
+ let mut first = true;
+
+ let subst = format!("{}", Fmt(|f| Display::fmt(subst, f)));
+ if subst != "[]" {
+ write!(f, "substitution {}", subst)?;
+ first = false;
+ }
+
+ let constraints = format!("{}", Fmt(|f| Debug::fmt(constraints, f)));
+ if constraints != "[]" {
+ if !first { write!(f, ", ")?; }
+ write!(f, "lifetime constraints {}", constraints)?;
+ first = false;
+ }
+
+ let _ = first;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Substitution<I> {
+ /// Displays the substitution in the form `< P0, .. Pn >`, or (if
+ /// the substitution is empty) as an empty string.
+ pub fn with_angle(&self, interner: I) -> Angle<'_, GenericArg<I>> {
+ Angle(self.as_slice(interner))
+ }
+}
+
+impl<I: Interner> Debug for Substitution<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ Display::fmt(self, fmt)
+ }
+}
+
+impl<I: Interner> Debug for Variances<I> {
+ fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error> {
+ I::debug_variances(self, fmt).unwrap_or_else(|| write!(fmt, "{:?}", self.interned))
+ }
+}
diff --git a/vendor/chalk-ir/src/fold.rs b/vendor/chalk-ir/src/fold.rs
new file mode 100644
index 000000000..b15cbff7a
--- /dev/null
+++ b/vendor/chalk-ir/src/fold.rs
@@ -0,0 +1,920 @@
+//! Traits for transforming bits of IR.
+
+use crate::*;
+use std::convert::Infallible;
+use std::fmt::Debug;
+
+mod binder_impls;
+mod boring_impls;
+mod in_place;
+pub mod shift;
+mod subst;
+
+pub use self::shift::Shift;
+pub use self::subst::Subst;
+
+/// A "folder" is a transformer that can be used to make a copy of
+/// some term -- that is, some bit of IR, such as a `Goal` -- with
+/// certain changes applied. The idea is that it contains methods that
+/// let you swap types/lifetimes for new types/lifetimes; meanwhile,
+/// each bit of IR implements the `TypeFoldable` trait which, given a
+/// `FallibleTypeFolder`, will reconstruct itself, invoking the folder's
+/// methods to transform each of the types/lifetimes embedded within.
+///
+/// As the name suggests, folds performed by `FallibleTypeFolder` can
+/// fail (with type `Error`); if the folder cannot fail, consider
+/// implementing `TypeFolder` instead (which is an infallible, but
+/// otherwise equivalent, trait).
+///
+/// # Usage patterns
+///
+/// ## Substituting for free variables
+///
+/// Most of the time, though, we are not interested in adjust
+/// arbitrary types/lifetimes, but rather just free variables (even
+/// more often, just free existential variables) that appear within
+/// the term.
+///
+/// For this reason, the `FallibleTypeFolder` trait extends two other
+/// traits that contain methods that are invoked when just those particular
+///
+/// In particular, folders can intercept references to free variables
+/// (either existentially or universally quantified) and replace them
+/// with other types/lifetimes as appropriate.
+///
+/// To create a folder `F`, one never implements `FallibleTypeFolder`
+/// directly, but instead implements one of each of these three sub-traits:
+///
+/// - `FreeVarFolder` -- folds `BoundVar` instances that appear free
+/// in the term being folded (use `DefaultFreeVarFolder` to
+/// ignore/forbid these altogether)
+/// - `InferenceFolder` -- folds existential `InferenceVar` instances
+/// that appear in the term being folded (use
+/// `DefaultInferenceFolder` to ignore/forbid these altogether)
+/// - `PlaceholderFolder` -- folds universal `Placeholder` instances
+/// that appear in the term being folded (use
+/// `DefaultPlaceholderFolder` to ignore/forbid these altogether)
+///
+/// To **apply** a folder, use the `TypeFoldable::try_fold_with` method,
+/// like so
+///
+/// ```rust,ignore
+/// let x = x.try_fold_with(&mut folder, 0);
+/// ```
+pub trait FallibleTypeFolder<I: Interner> {
+ /// The type this folder returns when folding fails. This is
+ /// commonly [`NoSolution`].
+ type Error;
+
+ /// Creates a `dyn` value from this folder. Unfortunately, this
+ /// must be added manually to each impl of FallibleTypeFolder; it
+ /// permits the default implements below to create a
+ /// `&mut dyn FallibleTypeFolder` from `Self` without knowing what
+ /// `Self` is (by invoking this method). Effectively, this limits
+ /// impls of `FallibleTypeFolder` to types for which we are able to
+ /// create a dyn value (i.e., not `[T]` types).
+ fn as_dyn(&mut self) -> &mut dyn FallibleTypeFolder<I, Error = Self::Error>;
+
+ /// Top-level callback: invoked for each `Ty<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `try_super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `try_fold_free_var_ty`.
+ fn try_fold_ty(
+ &mut self,
+ ty: Ty<I>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Ty<I>, Self::Error> {
+ ty.try_super_fold_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Lifetime<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `try_super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `try_fold_free_var_lifetime`.
+ fn try_fold_lifetime(
+ &mut self,
+ lifetime: Lifetime<I>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Lifetime<I>, Self::Error> {
+ lifetime.try_super_fold_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Const<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `try_super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `try_fold_free_var_const`.
+ fn try_fold_const(
+ &mut self,
+ constant: Const<I>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Const<I>, Self::Error> {
+ constant.try_super_fold_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Invoked for every program clause. By default, recursively folds the goals contents.
+ fn try_fold_program_clause(
+ &mut self,
+ clause: ProgramClause<I>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<ProgramClause<I>, Self::Error> {
+ clause.try_super_fold_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Invoked for every goal. By default, recursively folds the goals contents.
+ fn try_fold_goal(
+ &mut self,
+ goal: Goal<I>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Goal<I>, Self::Error> {
+ goal.try_super_fold_with(self.as_dyn(), outer_binder)
+ }
+
+ /// If overridden to return true, then folding will panic if a
+ /// free variable is encountered. This should be done if free
+ /// type/lifetime variables are not expected.
+ fn forbid_free_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for `TyKind::BoundVar` instances that are not bound
+ /// within the type being folded over:
+ ///
+ /// - `depth` is the depth of the `TyKind::BoundVar`; this has
+ /// been adjusted to account for binders in scope.
+ /// - `binders` is the number of binders in scope.
+ ///
+ /// This should return a type suitable for a context with
+ /// `binders` in scope.
+ fn try_fold_free_var_ty(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Ty<I>, Self::Error> {
+ if self.forbid_free_vars() {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ Ok(TyKind::<I>::BoundVar(bound_var).intern(self.interner()))
+ }
+ }
+
+ /// As `try_fold_free_var_ty`, but for lifetimes.
+ fn try_fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Lifetime<I>, Self::Error> {
+ if self.forbid_free_vars() {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ Ok(LifetimeData::<I>::BoundVar(bound_var).intern(self.interner()))
+ }
+ }
+
+ /// As `try_fold_free_var_ty`, but for constants.
+ fn try_fold_free_var_const(
+ &mut self,
+ ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Const<I>, Self::Error> {
+ if self.forbid_free_vars() {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ Ok(ConstData {
+ ty: ty.try_fold_with(self.as_dyn(), outer_binder)?,
+ value: ConstValue::<I>::BoundVar(bound_var),
+ }
+ .intern(self.interner()))
+ }
+ }
+
+ /// If overridden to return true, we will panic when a free
+ /// placeholder type/lifetime/const is encountered.
+ fn forbid_free_placeholders(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a placeholder type; these are
+ /// used when we instantiate binders universally. Returns a type
+ /// to use instead, which should be suitably shifted to account
+ /// for `binders`.
+ ///
+ /// - `universe` is the universe of the `TypeName::ForAll` that was found
+ /// - `binders` is the number of binders in scope
+ #[allow(unused_variables)]
+ fn try_fold_free_placeholder_ty(
+ &mut self,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Ty<I>, Self::Error> {
+ if self.forbid_free_placeholders() {
+ panic!("unexpected placeholder type `{:?}`", universe)
+ } else {
+ Ok(universe.to_ty::<I>(self.interner()))
+ }
+ }
+
+ /// As with `try_fold_free_placeholder_ty`, but for lifetimes.
+ #[allow(unused_variables)]
+ fn try_fold_free_placeholder_lifetime(
+ &mut self,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Lifetime<I>, Self::Error> {
+ if self.forbid_free_placeholders() {
+ panic!("unexpected placeholder lifetime `{:?}`", universe)
+ } else {
+ Ok(universe.to_lifetime(self.interner()))
+ }
+ }
+
+ /// As with `try_fold_free_placeholder_ty`, but for constants.
+ #[allow(unused_variables)]
+ fn try_fold_free_placeholder_const(
+ &mut self,
+ ty: Ty<I>,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Const<I>, Self::Error> {
+ if self.forbid_free_placeholders() {
+ panic!("unexpected placeholder const `{:?}`", universe)
+ } else {
+ Ok(universe.to_const(
+ self.interner(),
+ ty.try_fold_with(self.as_dyn(), outer_binder)?,
+ ))
+ }
+ }
+
+ /// If overridden to return true, inference variables will trigger
+ /// panics when folded. Used when inference variables are
+ /// unexpected.
+ fn forbid_inference_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a inference type; these are
+ /// used when we instantiate binders universally. Returns a type
+ /// to use instead, which should be suitably shifted to account
+ /// for `binders`.
+ ///
+ /// - `universe` is the universe of the `TypeName::ForAll` that was found
+ /// - `binders` is the number of binders in scope
+ #[allow(unused_variables)]
+ fn try_fold_inference_ty(
+ &mut self,
+ var: InferenceVar,
+ kind: TyVariableKind,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Ty<I>, Self::Error> {
+ if self.forbid_inference_vars() {
+ panic!("unexpected inference type `{:?}`", var)
+ } else {
+ Ok(var.to_ty(self.interner(), kind))
+ }
+ }
+
+ /// As with `try_fold_inference_ty`, but for lifetimes.
+ #[allow(unused_variables)]
+ fn try_fold_inference_lifetime(
+ &mut self,
+ var: InferenceVar,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Lifetime<I>, Self::Error> {
+ if self.forbid_inference_vars() {
+ panic!("unexpected inference lifetime `'{:?}`", var)
+ } else {
+ Ok(var.to_lifetime(self.interner()))
+ }
+ }
+
+ /// As with `try_fold_inference_ty`, but for constants.
+ #[allow(unused_variables)]
+ fn try_fold_inference_const(
+ &mut self,
+ ty: Ty<I>,
+ var: InferenceVar,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Const<I>, Self::Error> {
+ if self.forbid_inference_vars() {
+ panic!("unexpected inference const `{:?}`", var)
+ } else {
+ Ok(var.to_const(
+ self.interner(),
+ ty.try_fold_with(self.as_dyn(), outer_binder)?,
+ ))
+ }
+ }
+
+ /// Gets the interner that is being folded from.
+ fn interner(&self) -> I;
+}
+
+/// A "folder" is a transformer that can be used to make a copy of
+/// some term -- that is, some bit of IR, such as a `Goal` -- with
+/// certain changes applied. The idea is that it contains methods that
+/// let you swap types/lifetimes for new types/lifetimes; meanwhile,
+/// each bit of IR implements the `TypeFoldable` trait which, given a
+/// `TypeFolder`, will reconstruct itself, invoking the folder's methods
+/// to transform each of the types/lifetimes embedded within.
+///
+/// Folds performed by `TypeFolder` cannot fail. If folds might fail,
+/// consider implementing `FallibleTypeFolder` instead (which is a
+/// fallible, but otherwise equivalent, trait).
+///
+/// # Usage patterns
+///
+/// ## Substituting for free variables
+///
+/// Most of the time, though, we are not interested in adjust
+/// arbitrary types/lifetimes, but rather just free variables (even
+/// more often, just free existential variables) that appear within
+/// the term.
+///
+/// For this reason, the `TypeFolder` trait extends two other traits that
+/// contain methods that are invoked when just those particular
+///
+/// In particular, folders can intercept references to free variables
+/// (either existentially or universally quantified) and replace them
+/// with other types/lifetimes as appropriate.
+///
+/// To create a folder `F`, one never implements `TypeFolder` directly, but instead
+/// implements one of each of these three sub-traits:
+///
+/// - `FreeVarFolder` -- folds `BoundVar` instances that appear free
+/// in the term being folded (use `DefaultFreeVarFolder` to
+/// ignore/forbid these altogether)
+/// - `InferenceFolder` -- folds existential `InferenceVar` instances
+/// that appear in the term being folded (use
+/// `DefaultInferenceFolder` to ignore/forbid these altogether)
+/// - `PlaceholderFolder` -- folds universal `Placeholder` instances
+/// that appear in the term being folded (use
+/// `DefaultPlaceholderFolder` to ignore/forbid these altogether)
+///
+/// To **apply** a folder, use the `TypeFoldable::fold_with` method, like so
+///
+/// ```rust,ignore
+/// let x = x.fold_with(&mut folder, 0);
+/// ```
+pub trait TypeFolder<I: Interner>: FallibleTypeFolder<I, Error = Infallible> {
+ /// Creates a `dyn` value from this folder. Unfortunately, this
+ /// must be added manually to each impl of TypeFolder; it permits the
+ /// default implements below to create a `&mut dyn TypeFolder` from
+ /// `Self` without knowing what `Self` is (by invoking this
+ /// method). Effectively, this limits impls of `TypeFolder` to types
+ /// for which we are able to create a dyn value (i.e., not `[T]`
+ /// types).
+ fn as_dyn(&mut self) -> &mut dyn TypeFolder<I>;
+
+ /// Top-level callback: invoked for each `Ty<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `fold_free_var_ty`.
+ fn fold_ty(&mut self, ty: Ty<I>, outer_binder: DebruijnIndex) -> Ty<I> {
+ ty.super_fold_with(TypeFolder::as_dyn(self), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Lifetime<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `fold_free_var_lifetime`.
+ fn fold_lifetime(&mut self, lifetime: Lifetime<I>, outer_binder: DebruijnIndex) -> Lifetime<I> {
+ lifetime.super_fold_with(TypeFolder::as_dyn(self), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Const<I>` that is
+ /// encountered when folding. By default, invokes
+ /// `super_fold_with`, which will in turn invoke the more
+ /// specialized folding methods below, like `fold_free_var_const`.
+ fn fold_const(&mut self, constant: Const<I>, outer_binder: DebruijnIndex) -> Const<I> {
+ constant.super_fold_with(TypeFolder::as_dyn(self), outer_binder)
+ }
+
+ /// Invoked for every program clause. By default, recursively folds the goals contents.
+ fn fold_program_clause(
+ &mut self,
+ clause: ProgramClause<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ProgramClause<I> {
+ clause.super_fold_with(TypeFolder::as_dyn(self), outer_binder)
+ }
+
+ /// Invoked for every goal. By default, recursively folds the goals contents.
+ fn fold_goal(&mut self, goal: Goal<I>, outer_binder: DebruijnIndex) -> Goal<I> {
+ goal.super_fold_with(TypeFolder::as_dyn(self), outer_binder)
+ }
+
+ /// If overridden to return true, then folding will panic if a
+ /// free variable is encountered. This should be done if free
+ /// type/lifetime variables are not expected.
+ fn forbid_free_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for `TyKind::BoundVar` instances that are not bound
+ /// within the type being folded over:
+ ///
+ /// - `depth` is the depth of the `TyKind::BoundVar`; this has
+ /// been adjusted to account for binders in scope.
+ /// - `binders` is the number of binders in scope.
+ ///
+ /// This should return a type suitable for a context with
+ /// `binders` in scope.
+ fn fold_free_var_ty(&mut self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> Ty<I> {
+ if TypeFolder::forbid_free_vars(self) {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ TyKind::<I>::BoundVar(bound_var).intern(TypeFolder::interner(self))
+ }
+ }
+
+ /// As `fold_free_var_ty`, but for lifetimes.
+ fn fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ if TypeFolder::forbid_free_vars(self) {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ LifetimeData::<I>::BoundVar(bound_var).intern(TypeFolder::interner(self))
+ }
+ }
+
+ /// As `fold_free_var_ty`, but for constants.
+ fn fold_free_var_const(
+ &mut self,
+ ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ if TypeFolder::forbid_free_vars(self) {
+ panic!(
+ "unexpected free variable with depth `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ let bound_var = bound_var.shifted_in_from(outer_binder);
+ ConstData {
+ ty: ty.fold_with(TypeFolder::as_dyn(self), outer_binder),
+ value: ConstValue::<I>::BoundVar(bound_var),
+ }
+ .intern(TypeFolder::interner(self))
+ }
+ }
+
+ /// If overridden to return true, we will panic when a free
+ /// placeholder type/lifetime/const is encountered.
+ fn forbid_free_placeholders(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a placeholder type; these are
+ /// used when we instantiate binders universally. Returns a type
+ /// to use instead, which should be suitably shifted to account
+ /// for `binders`.
+ ///
+ /// - `universe` is the universe of the `TypeName::ForAll` that was found
+ /// - `binders` is the number of binders in scope
+ #[allow(unused_variables)]
+ fn fold_free_placeholder_ty(
+ &mut self,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Ty<I> {
+ if TypeFolder::forbid_free_placeholders(self) {
+ panic!("unexpected placeholder type `{:?}`", universe)
+ } else {
+ universe.to_ty::<I>(TypeFolder::interner(self))
+ }
+ }
+
+ /// As with `fold_free_placeholder_ty`, but for lifetimes.
+ #[allow(unused_variables)]
+ fn fold_free_placeholder_lifetime(
+ &mut self,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ if TypeFolder::forbid_free_placeholders(self) {
+ panic!("unexpected placeholder lifetime `{:?}`", universe)
+ } else {
+ universe.to_lifetime(TypeFolder::interner(self))
+ }
+ }
+
+ /// As with `fold_free_placeholder_ty`, but for constants.
+ #[allow(unused_variables)]
+ fn fold_free_placeholder_const(
+ &mut self,
+ ty: Ty<I>,
+ universe: PlaceholderIndex,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ if TypeFolder::forbid_free_placeholders(self) {
+ panic!("unexpected placeholder const `{:?}`", universe)
+ } else {
+ universe.to_const(
+ TypeFolder::interner(self),
+ ty.fold_with(TypeFolder::as_dyn(self), outer_binder),
+ )
+ }
+ }
+
+ /// If overridden to return true, inference variables will trigger
+ /// panics when folded. Used when inference variables are
+ /// unexpected.
+ fn forbid_inference_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a inference type; these are
+ /// used when we instantiate binders universally. Returns a type
+ /// to use instead, which should be suitably shifted to account
+ /// for `binders`.
+ ///
+ /// - `universe` is the universe of the `TypeName::ForAll` that was found
+ /// - `binders` is the number of binders in scope
+ #[allow(unused_variables)]
+ fn fold_inference_ty(
+ &mut self,
+ var: InferenceVar,
+ kind: TyVariableKind,
+ outer_binder: DebruijnIndex,
+ ) -> Ty<I> {
+ if TypeFolder::forbid_inference_vars(self) {
+ panic!("unexpected inference type `{:?}`", var)
+ } else {
+ var.to_ty(TypeFolder::interner(self), kind)
+ }
+ }
+
+ /// As with `fold_inference_ty`, but for lifetimes.
+ #[allow(unused_variables)]
+ fn fold_inference_lifetime(
+ &mut self,
+ var: InferenceVar,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ if TypeFolder::forbid_inference_vars(self) {
+ panic!("unexpected inference lifetime `'{:?}`", var)
+ } else {
+ var.to_lifetime(TypeFolder::interner(self))
+ }
+ }
+
+ /// As with `fold_inference_ty`, but for constants.
+ #[allow(unused_variables)]
+ fn fold_inference_const(
+ &mut self,
+ ty: Ty<I>,
+ var: InferenceVar,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ if TypeFolder::forbid_inference_vars(self) {
+ panic!("unexpected inference const `{:?}`", var)
+ } else {
+ var.to_const(
+ TypeFolder::interner(self),
+ ty.fold_with(TypeFolder::as_dyn(self), outer_binder),
+ )
+ }
+ }
+
+ /// Gets the interner that is being folded from.
+ fn interner(&self) -> I;
+}
+
+/// Applies the given `TypeFolder` to a value, producing a folded result
+/// of type `Self::Result`. The result type is typically the same as
+/// the source type, but in some cases we convert from borrowed
+/// to owned as well (e.g., the folder for `&T` will fold to a fresh
+/// `T`; well, actually `T::Result`).
+pub trait TypeFoldable<I: Interner>: Debug + Sized {
+ /// Apply the given folder `folder` to `self`; `binders` is the
+ /// number of binders that are in scope when beginning the
+ /// folder. Typically `binders` starts as 0, but is adjusted when
+ /// we encounter `Binders<T>` in the IR or other similar
+ /// constructs.
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E>;
+
+ /// A convenient alternative to `try_fold_with` for use with infallible
+ /// folders. Do not override this method, to ensure coherence with
+ /// `try_fold_with`.
+ fn fold_with(self, folder: &mut dyn TypeFolder<I>, outer_binder: DebruijnIndex) -> Self {
+ self.try_fold_with(FallibleTypeFolder::as_dyn(folder), outer_binder)
+ .unwrap()
+ }
+}
+
+/// For types where "fold" invokes a callback on the `TypeFolder`, the
+/// `TypeSuperFoldable` trait captures the recursive behavior that folds all
+/// the contents of the type.
+pub trait TypeSuperFoldable<I: Interner>: TypeFoldable<I> {
+ /// Recursively folds the value.
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E>;
+
+ /// A convenient alternative to `try_super_fold_with` for use with
+ /// infallible folders. Do not override this method, to ensure coherence
+ /// with `try_super_fold_with`.
+ fn super_fold_with(self, folder: &mut dyn TypeFolder<I>, outer_binder: DebruijnIndex) -> Self {
+ self.try_super_fold_with(FallibleTypeFolder::as_dyn(folder), outer_binder)
+ .unwrap()
+ }
+}
+
+/// "Folding" a type invokes the `try_fold_ty` method on the folder; this
+/// usually (in turn) invokes `try_super_fold_ty` to fold the individual
+/// parts.
+impl<I: Interner> TypeFoldable<I> for Ty<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ folder.try_fold_ty(self, outer_binder)
+ }
+}
+
+/// "Super fold" for a type invokes te more detailed callbacks on the type
+impl<I> TypeSuperFoldable<I> for Ty<I>
+where
+ I: Interner,
+{
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Ty<I>, E> {
+ let interner = folder.interner();
+ Ok(match self.kind(interner) {
+ TyKind::BoundVar(bound_var) => {
+ if let Some(bound_var1) = bound_var.shifted_out_to(outer_binder) {
+ // This variable was bound outside of the binders
+ // that we have traversed during folding;
+ // therefore, it is free. Let the folder have a
+ // crack at it.
+ folder.try_fold_free_var_ty(bound_var1, outer_binder)?
+ } else {
+ // This variable was bound within the binders that
+ // we folded over, so just return a bound
+ // variable.
+ self
+ }
+ }
+ TyKind::Dyn(clauses) => {
+ TyKind::Dyn(clauses.clone().try_fold_with(folder, outer_binder)?)
+ .intern(folder.interner())
+ }
+ TyKind::InferenceVar(var, kind) => {
+ folder.try_fold_inference_ty(*var, *kind, outer_binder)?
+ }
+ TyKind::Placeholder(ui) => folder.try_fold_free_placeholder_ty(*ui, outer_binder)?,
+ TyKind::Alias(proj) => TyKind::Alias(proj.clone().try_fold_with(folder, outer_binder)?)
+ .intern(folder.interner()),
+ TyKind::Function(fun) => {
+ TyKind::Function(fun.clone().try_fold_with(folder, outer_binder)?)
+ .intern(folder.interner())
+ }
+ TyKind::Adt(id, substitution) => TyKind::Adt(
+ id.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::AssociatedType(assoc_ty, substitution) => TyKind::AssociatedType(
+ assoc_ty.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Scalar(scalar) => TyKind::Scalar(scalar.try_fold_with(folder, outer_binder)?)
+ .intern(folder.interner()),
+ TyKind::Str => TyKind::Str.intern(folder.interner()),
+ TyKind::Tuple(arity, substitution) => TyKind::Tuple(
+ *arity,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::OpaqueType(opaque_ty, substitution) => TyKind::OpaqueType(
+ opaque_ty.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Slice(substitution) => {
+ TyKind::Slice(substitution.clone().try_fold_with(folder, outer_binder)?)
+ .intern(folder.interner())
+ }
+ TyKind::FnDef(fn_def, substitution) => TyKind::FnDef(
+ fn_def.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Ref(mutability, lifetime, ty) => TyKind::Ref(
+ mutability.try_fold_with(folder, outer_binder)?,
+ lifetime.clone().try_fold_with(folder, outer_binder)?,
+ ty.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Raw(mutability, ty) => TyKind::Raw(
+ mutability.try_fold_with(folder, outer_binder)?,
+ ty.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Never => TyKind::Never.intern(folder.interner()),
+ TyKind::Array(ty, const_) => TyKind::Array(
+ ty.clone().try_fold_with(folder, outer_binder)?,
+ const_.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Closure(id, substitution) => TyKind::Closure(
+ id.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Generator(id, substitution) => TyKind::Generator(
+ id.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::GeneratorWitness(id, substitution) => TyKind::GeneratorWitness(
+ id.try_fold_with(folder, outer_binder)?,
+ substitution.clone().try_fold_with(folder, outer_binder)?,
+ )
+ .intern(folder.interner()),
+ TyKind::Foreign(id) => {
+ TyKind::Foreign(id.try_fold_with(folder, outer_binder)?).intern(folder.interner())
+ }
+ TyKind::Error => TyKind::Error.intern(folder.interner()),
+ })
+ }
+}
+
+/// "Folding" a lifetime invokes the `fold_lifetime` method on the folder; this
+/// usually (in turn) invokes `super_fold_lifetime` to fold the individual
+/// parts.
+impl<I: Interner> TypeFoldable<I> for Lifetime<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ folder.try_fold_lifetime(self, outer_binder)
+ }
+}
+
+impl<I> TypeSuperFoldable<I> for Lifetime<I>
+where
+ I: Interner,
+{
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Lifetime<I>, E> {
+ let interner = folder.interner();
+ match self.data(interner) {
+ LifetimeData::BoundVar(bound_var) => {
+ if let Some(bound_var1) = bound_var.shifted_out_to(outer_binder) {
+ // This variable was bound outside of the binders
+ // that we have traversed during folding;
+ // therefore, it is free. Let the folder have a
+ // crack at it.
+ folder.try_fold_free_var_lifetime(bound_var1, outer_binder)
+ } else {
+ // This variable was bound within the binders that
+ // we folded over, so just return a bound
+ // variable.
+ Ok(self)
+ }
+ }
+ LifetimeData::InferenceVar(var) => {
+ folder.try_fold_inference_lifetime(*var, outer_binder)
+ }
+ LifetimeData::Placeholder(universe) => {
+ folder.try_fold_free_placeholder_lifetime(*universe, outer_binder)
+ }
+ LifetimeData::Static => Ok(LifetimeData::<I>::Static.intern(folder.interner())),
+ LifetimeData::Erased => Ok(LifetimeData::<I>::Erased.intern(folder.interner())),
+ LifetimeData::Phantom(void, ..) => match *void {},
+ }
+ }
+}
+
+/// "Folding" a const invokes the `fold_const` method on the folder; this
+/// usually (in turn) invokes `super_fold_const` to fold the individual
+/// parts.
+impl<I: Interner> TypeFoldable<I> for Const<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ folder.try_fold_const(self, outer_binder)
+ }
+}
+
+impl<I> TypeSuperFoldable<I> for Const<I>
+where
+ I: Interner,
+{
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Const<I>, E> {
+ let interner = folder.interner();
+ let ConstData { ref ty, ref value } = self.data(interner);
+ let mut fold_ty = || ty.clone().try_fold_with(folder, outer_binder);
+ match value {
+ ConstValue::BoundVar(bound_var) => {
+ if let Some(bound_var1) = bound_var.shifted_out_to(outer_binder) {
+ folder.try_fold_free_var_const(ty.clone(), bound_var1, outer_binder)
+ } else {
+ Ok(self)
+ }
+ }
+ ConstValue::InferenceVar(var) => {
+ folder.try_fold_inference_const(ty.clone(), *var, outer_binder)
+ }
+ ConstValue::Placeholder(universe) => {
+ folder.try_fold_free_placeholder_const(ty.clone(), *universe, outer_binder)
+ }
+ ConstValue::Concrete(ev) => Ok(ConstData {
+ ty: fold_ty()?,
+ value: ConstValue::Concrete(ConcreteConst {
+ interned: ev.interned.clone(),
+ }),
+ }
+ .intern(folder.interner())),
+ }
+ }
+}
+
+/// Folding a goal invokes the `fold_goal` callback (which will, by
+/// default, invoke super-fold).
+impl<I: Interner> TypeFoldable<I> for Goal<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ folder.try_fold_goal(self, outer_binder)
+ }
+}
+
+/// Superfold folds recursively.
+impl<I: Interner> TypeSuperFoldable<I> for Goal<I> {
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+ Ok(Goal::new(
+ interner,
+ self.data(interner)
+ .clone()
+ .try_fold_with(folder, outer_binder)?,
+ ))
+ }
+}
+
+/// Folding a program clause invokes the `fold_program_clause`
+/// callback on the folder (which will, by default, invoke the
+/// `super_fold_with` method on the program clause).
+impl<I: Interner> TypeFoldable<I> for ProgramClause<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ folder.try_fold_program_clause(self, outer_binder)
+ }
+}
diff --git a/vendor/chalk-ir/src/fold/binder_impls.rs b/vendor/chalk-ir/src/fold/binder_impls.rs
new file mode 100644
index 000000000..1f44c1629
--- /dev/null
+++ b/vendor/chalk-ir/src/fold/binder_impls.rs
@@ -0,0 +1,73 @@
+//! This module contains impls of `TypeFoldable` for those types that
+//! introduce binders.
+//!
+//! The more interesting impls of `TypeFoldable` remain in the `fold` module.
+
+use crate::*;
+
+impl<I: Interner> TypeFoldable<I> for FnPointer<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let FnPointer {
+ num_binders,
+ substitution,
+ sig,
+ } = self;
+ Ok(FnPointer {
+ num_binders,
+ substitution: substitution.try_fold_with(folder, outer_binder.shifted_in())?,
+ sig: FnSig {
+ abi: sig.abi,
+ safety: sig.safety,
+ variadic: sig.variadic,
+ },
+ })
+ }
+}
+
+impl<T, I: Interner> TypeFoldable<I> for Binders<T>
+where
+ T: HasInterner<Interner = I> + TypeFoldable<I>,
+ I: Interner,
+{
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let Binders {
+ binders: self_binders,
+ value: self_value,
+ } = self;
+ let value = self_value.try_fold_with(folder, outer_binder.shifted_in())?;
+ let binders = VariableKinds {
+ interned: self_binders.interned().clone(),
+ };
+ Ok(Binders::new(binders, value))
+ }
+}
+
+impl<I, T> TypeFoldable<I> for Canonical<T>
+where
+ I: Interner,
+ T: HasInterner<Interner = I> + TypeFoldable<I>,
+{
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let Canonical {
+ binders: self_binders,
+ value: self_value,
+ } = self;
+ let value = self_value.try_fold_with(folder, outer_binder.shifted_in())?;
+ let binders = CanonicalVarKinds {
+ interned: self_binders.interned().clone(),
+ };
+ Ok(Canonical { binders, value })
+ }
+}
diff --git a/vendor/chalk-ir/src/fold/boring_impls.rs b/vendor/chalk-ir/src/fold/boring_impls.rs
new file mode 100644
index 000000000..fb4e3e30b
--- /dev/null
+++ b/vendor/chalk-ir/src/fold/boring_impls.rs
@@ -0,0 +1,244 @@
+//! This module contains "rote and uninteresting" impls of `TypeFoldable` for
+//! various types. In general, we prefer to derive `TypeFoldable`, but
+//! sometimes that doesn't work for whatever reason.
+//!
+//! The more interesting impls of `TypeFoldable` remain in the `fold` module.
+
+use super::in_place;
+use crate::*;
+use std::marker::PhantomData;
+
+impl<T: TypeFoldable<I>, I: Interner> TypeFoldable<I> for Vec<T> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ in_place::fallible_map_vec(self, |e| e.try_fold_with(folder, outer_binder))
+ }
+}
+
+impl<T: TypeFoldable<I>, I: Interner> TypeFoldable<I> for Box<T> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ in_place::fallible_map_box(self, |e| e.try_fold_with(folder, outer_binder))
+ }
+}
+
+macro_rules! tuple_fold {
+ ($($n:ident),*) => {
+ impl<$($n: TypeFoldable<I>,)* I: Interner> TypeFoldable<I> for ($($n,)*) {
+ fn try_fold_with<Error>(self, folder: &mut dyn FallibleTypeFolder<I, Error = Error>, outer_binder: DebruijnIndex) -> Result<Self, Error>
+ {
+ #[allow(non_snake_case)]
+ let ($($n),*) = self;
+ Ok(($($n.try_fold_with(folder, outer_binder)?,)*))
+ }
+ }
+ }
+}
+
+tuple_fold!(A, B);
+tuple_fold!(A, B, C);
+tuple_fold!(A, B, C, D);
+tuple_fold!(A, B, C, D, E);
+
+impl<T: TypeFoldable<I>, I: Interner> TypeFoldable<I> for Option<T> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ match self {
+ None => Ok(None),
+ Some(e) => Ok(Some(e.try_fold_with(folder, outer_binder)?)),
+ }
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for GenericArg<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+
+ let data = self
+ .data(interner)
+ .clone()
+ .try_fold_with(folder, outer_binder)?;
+ Ok(GenericArg::new(interner, data))
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for Substitution<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+
+ let folded = self
+ .iter(interner)
+ .cloned()
+ .map(|p| p.try_fold_with(folder, outer_binder));
+ Substitution::from_fallible(interner, folded)
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for Goals<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+ let folded = self
+ .iter(interner)
+ .cloned()
+ .map(|p| p.try_fold_with(folder, outer_binder));
+ Goals::from_fallible(interner, folded)
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for ProgramClauses<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+ let folded = self
+ .iter(interner)
+ .cloned()
+ .map(|p| p.try_fold_with(folder, outer_binder));
+ ProgramClauses::from_fallible(interner, folded)
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for QuantifiedWhereClauses<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+ let folded = self
+ .iter(interner)
+ .cloned()
+ .map(|p| p.try_fold_with(folder, outer_binder));
+ QuantifiedWhereClauses::from_fallible(interner, folded)
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for Constraints<I> {
+ fn try_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> Result<Self, E> {
+ let interner = folder.interner();
+ let folded = self
+ .iter(interner)
+ .cloned()
+ .map(|p| p.try_fold_with(folder, outer_binder));
+ Constraints::from_fallible(interner, folded)
+ }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! copy_fold {
+ ($t:ty) => {
+ impl<I: Interner> $crate::fold::TypeFoldable<I> for $t {
+ fn try_fold_with<E>(
+ self,
+ _folder: &mut dyn ($crate::fold::FallibleTypeFolder<I, Error = E>),
+ _outer_binder: DebruijnIndex,
+ ) -> ::std::result::Result<Self, E> {
+ Ok(self)
+ }
+ }
+ };
+}
+
+copy_fold!(bool);
+copy_fold!(usize);
+copy_fold!(UniverseIndex);
+copy_fold!(PlaceholderIndex);
+copy_fold!(QuantifierKind);
+copy_fold!(DebruijnIndex);
+copy_fold!(());
+copy_fold!(UintTy);
+copy_fold!(IntTy);
+copy_fold!(FloatTy);
+copy_fold!(Scalar);
+copy_fold!(ClausePriority);
+copy_fold!(Mutability);
+copy_fold!(Safety);
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! id_fold {
+ ($t:ident) => {
+ impl<I: Interner> $crate::fold::TypeFoldable<I> for $t<I> {
+ fn try_fold_with<E>(
+ self,
+ _folder: &mut dyn ($crate::fold::FallibleTypeFolder<I, Error = E>),
+ _outer_binder: DebruijnIndex,
+ ) -> ::std::result::Result<Self, E> {
+ Ok(self)
+ }
+ }
+ };
+}
+
+id_fold!(ImplId);
+id_fold!(AdtId);
+id_fold!(TraitId);
+id_fold!(AssocTypeId);
+id_fold!(OpaqueTyId);
+id_fold!(FnDefId);
+id_fold!(ClosureId);
+id_fold!(GeneratorId);
+id_fold!(ForeignDefId);
+
+impl<I: Interner> TypeSuperFoldable<I> for ProgramClauseData<I> {
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> ::std::result::Result<Self, E> {
+ Ok(ProgramClauseData(
+ self.0.try_fold_with(folder, outer_binder)?,
+ ))
+ }
+}
+
+impl<I: Interner> TypeSuperFoldable<I> for ProgramClause<I> {
+ fn try_super_fold_with<E>(
+ self,
+ folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ outer_binder: DebruijnIndex,
+ ) -> ::std::result::Result<Self, E> {
+ let clause = self.data(folder.interner()).clone();
+ Ok(clause
+ .try_super_fold_with(folder, outer_binder)?
+ .intern(folder.interner()))
+ }
+}
+
+impl<I: Interner> TypeFoldable<I> for PhantomData<I> {
+ fn try_fold_with<E>(
+ self,
+ _folder: &mut dyn FallibleTypeFolder<I, Error = E>,
+ _outer_binder: DebruijnIndex,
+ ) -> ::std::result::Result<Self, E> {
+ Ok(PhantomData)
+ }
+}
diff --git a/vendor/chalk-ir/src/fold/in_place.rs b/vendor/chalk-ir/src/fold/in_place.rs
new file mode 100644
index 000000000..263da617d
--- /dev/null
+++ b/vendor/chalk-ir/src/fold/in_place.rs
@@ -0,0 +1,263 @@
+//! Subroutines to help implementers of `TypeFoldable` avoid unnecessary heap allocations.
+
+use std::marker::PhantomData;
+use std::{mem, ptr};
+
+fn is_zst<T>() -> bool {
+ mem::size_of::<T>() == 0
+}
+
+fn is_layout_identical<T, U>() -> bool {
+ mem::size_of::<T>() == mem::size_of::<U>() && mem::align_of::<T>() == mem::align_of::<U>()
+}
+
+/// Maps a `Box<T>` to a `Box<U>`, reusing the underlying storage if possible.
+pub(super) fn fallible_map_box<T, U, E>(
+ b: Box<T>,
+ map: impl FnOnce(T) -> Result<U, E>,
+) -> Result<Box<U>, E> {
+ // This optimization is only valid when `T` and `U` have the same size/alignment and is not
+ // useful for ZSTs.
+ if !is_layout_identical::<T, U>() || is_zst::<T>() {
+ return map(*b).map(Box::new);
+ }
+
+ let raw = Box::into_raw(b);
+ unsafe {
+ let val = ptr::read(raw);
+
+ // Box<T> -> Box<MaybeUninit<U>>
+ let mut raw: Box<mem::MaybeUninit<U>> = Box::from_raw(raw.cast());
+
+ // If `map` panics or returns an error, `raw` will free the memory associated with `b`, but
+ // not drop the boxed value itself since it is wrapped in `MaybeUninit`. This is what we
+ // want since the boxed value was moved into `map`.
+ let mapped_val = map(val)?;
+ ptr::write(raw.as_mut_ptr(), mapped_val);
+
+ // Box<MaybeUninit<U>> -> Box<U>
+ Ok(Box::from_raw(Box::into_raw(raw).cast()))
+ }
+}
+
+/// Maps a `Vec<T>` to a `Vec<U>`, reusing the underlying storage if possible.
+pub(super) fn fallible_map_vec<T, U, E>(
+ vec: Vec<T>,
+ mut map: impl FnMut(T) -> Result<U, E>,
+) -> Result<Vec<U>, E> {
+ // This optimization is only valid when `T` and `U` have the same size/alignment and is not
+ // useful for ZSTs.
+ if !is_layout_identical::<T, U>() || is_zst::<T>() {
+ return vec.into_iter().map(map).collect();
+ }
+
+ let mut vec = VecMappedInPlace::<T, U>::new(vec);
+
+ unsafe {
+ for i in 0..vec.len {
+ let place = vec.ptr.add(i);
+ let val = ptr::read(place);
+
+ // Set `map_in_progress` so the drop impl for `VecMappedInPlace` can handle the other
+ // elements correctly in case `map` panics or returns an error.
+ vec.map_in_progress = i;
+ let mapped_val = map(val)?;
+
+ ptr::write(place as *mut U, mapped_val);
+ }
+
+ Ok(vec.finish())
+ }
+}
+
+/// Takes ownership of a `Vec` that is being mapped in place, cleaning up if the map fails.
+struct VecMappedInPlace<T, U> {
+ ptr: *mut T,
+ len: usize,
+ cap: usize,
+
+ map_in_progress: usize,
+ _elem_tys: PhantomData<(T, U)>,
+}
+
+impl<T, U> VecMappedInPlace<T, U> {
+ fn new(mut vec: Vec<T>) -> Self {
+ assert!(is_layout_identical::<T, U>());
+
+ // FIXME: This is just `Vec::into_raw_parts`. Use that instead when it is stabilized.
+ let ptr = vec.as_mut_ptr();
+ let len = vec.len();
+ let cap = vec.capacity();
+ mem::forget(vec);
+
+ VecMappedInPlace {
+ ptr,
+ len,
+ cap,
+
+ map_in_progress: 0,
+ _elem_tys: PhantomData,
+ }
+ }
+
+ /// Converts back into a `Vec` once the map is complete.
+ unsafe fn finish(self) -> Vec<U> {
+ let this = mem::ManuallyDrop::new(self);
+ Vec::from_raw_parts(this.ptr as *mut U, this.len, this.cap)
+ }
+}
+
+/// `VecMappedInPlace` drops everything but the element that was passed to `map` when it panicked or
+/// returned an error. Everything before that index in the vector has type `U` (it has been mapped)
+/// and everything after it has type `T` (it has not been mapped).
+///
+/// ```text
+/// mapped
+/// | not yet mapped
+/// |----| |-----|
+/// [UUUU UxTT TTTT]
+/// ^
+/// `map_in_progress` (not dropped)
+/// ```
+impl<T, U> Drop for VecMappedInPlace<T, U> {
+ fn drop(&mut self) {
+ // Drop mapped elements of type `U`.
+ for i in 0..self.map_in_progress {
+ unsafe {
+ ptr::drop_in_place(self.ptr.add(i) as *mut U);
+ }
+ }
+
+ // Drop unmapped elements of type `T`.
+ for i in (self.map_in_progress + 1)..self.len {
+ unsafe {
+ ptr::drop_in_place(self.ptr.add(i));
+ }
+ }
+
+ // Free the underlying storage for the `Vec`.
+ // `len` is 0 because the elements were handled above.
+ unsafe {
+ Vec::from_raw_parts(self.ptr, 0, self.cap);
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use std::fmt;
+ use std::sync::{Arc, Mutex};
+
+ /// A wrapper around `T` that records when it is dropped.
+ struct RecordDrop<T: fmt::Display> {
+ id: T,
+ drops: Arc<Mutex<Vec<String>>>,
+ }
+
+ impl<T: fmt::Display> RecordDrop<T> {
+ fn new(id: T, drops: &Arc<Mutex<Vec<String>>>) -> Self {
+ RecordDrop {
+ id,
+ drops: drops.clone(),
+ }
+ }
+ }
+
+ impl RecordDrop<u8> {
+ fn map_to_char(self) -> RecordDrop<char> {
+ let this = std::mem::ManuallyDrop::new(self);
+ RecordDrop {
+ id: (this.id + b'A') as char,
+ drops: this.drops.clone(),
+ }
+ }
+ }
+
+ impl<T: fmt::Display> Drop for RecordDrop<T> {
+ fn drop(&mut self) {
+ self.drops.lock().unwrap().push(format!("{}", self.id));
+ }
+ }
+
+ #[test]
+ fn vec_no_cleanup_after_success() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = (0u8..5).map(|i| RecordDrop::new(i, &drops)).collect();
+
+ let res: Result<_, ()> = super::fallible_map_vec(to_fold, |x| Ok(x.map_to_char()));
+
+ assert!(res.is_ok());
+ assert!(drops.lock().unwrap().is_empty());
+ }
+
+ #[test]
+ fn vec_cleanup_after_panic() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = (0u8..5).map(|i| RecordDrop::new(i, &drops)).collect();
+
+ let res = std::panic::catch_unwind(|| {
+ let _: Result<_, ()> = super::fallible_map_vec(to_fold, |x| {
+ if x.id == 3 {
+ panic!();
+ }
+
+ Ok(x.map_to_char())
+ });
+ });
+
+ assert!(res.is_err());
+ assert_eq!(*drops.lock().unwrap(), &["3", "A", "B", "C", "4"]);
+ }
+
+ #[test]
+ fn vec_cleanup_after_early_return() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = (0u8..5).map(|i| RecordDrop::new(i, &drops)).collect();
+
+ let res = super::fallible_map_vec(to_fold, |x| {
+ if x.id == 2 {
+ return Err(());
+ }
+
+ Ok(x.map_to_char())
+ });
+
+ assert!(res.is_err());
+ assert_eq!(*drops.lock().unwrap(), &["2", "A", "B", "3", "4"]);
+ }
+
+ #[test]
+ fn box_no_cleanup_after_success() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = Box::new(RecordDrop::new(0, &drops));
+
+ let res: Result<Box<_>, ()> = super::fallible_map_box(to_fold, |x| Ok(x.map_to_char()));
+
+ assert!(res.is_ok());
+ assert!(drops.lock().unwrap().is_empty());
+ }
+
+ #[test]
+ fn box_cleanup_after_panic() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = Box::new(RecordDrop::new(0, &drops));
+
+ let res = std::panic::catch_unwind(|| {
+ let _: Result<Box<()>, ()> = super::fallible_map_box(to_fold, |_| panic!());
+ });
+
+ assert!(res.is_err());
+ assert_eq!(*drops.lock().unwrap(), &["0"]);
+ }
+
+ #[test]
+ fn box_cleanup_after_early_return() {
+ let drops = Arc::new(Mutex::new(Vec::new()));
+ let to_fold = Box::new(RecordDrop::new(0, &drops));
+
+ let res: Result<Box<()>, _> = super::fallible_map_box(to_fold, |_| Err(()));
+
+ assert!(res.is_err());
+ assert_eq!(*drops.lock().unwrap(), &["0"]);
+ }
+}
diff --git a/vendor/chalk-ir/src/fold/shift.rs b/vendor/chalk-ir/src/fold/shift.rs
new file mode 100644
index 000000000..f7e5e4a4a
--- /dev/null
+++ b/vendor/chalk-ir/src/fold/shift.rs
@@ -0,0 +1,177 @@
+//! Shifting of debruijn indices
+
+use crate::*;
+
+/// Methods for converting debruijn indices to move values into or out
+/// of binders.
+pub trait Shift<I: Interner>: TypeFoldable<I> {
+ /// Shifts this term in one level of binders.
+ fn shifted_in(self, interner: I) -> Self;
+
+ /// Shifts a term valid at `outer_binder` so that it is
+ /// valid at the innermost binder. See [`DebruijnIndex::shifted_in_from`]
+ /// for a detailed explanation.
+ fn shifted_in_from(self, interner: I, source_binder: DebruijnIndex) -> Self;
+
+ /// Shifts this term out one level of binders.
+ fn shifted_out(self, interner: I) -> Fallible<Self>;
+
+ /// Shifts a term valid at the innermost binder so that it is
+ /// valid at `outer_binder`. See [`DebruijnIndex::shifted_out_to`]
+ /// for a detailed explanation.
+ fn shifted_out_to(self, interner: I, target_binder: DebruijnIndex) -> Fallible<Self>;
+}
+
+impl<T: TypeFoldable<I>, I: Interner> Shift<I> for T {
+ fn shifted_in(self, interner: I) -> Self {
+ self.shifted_in_from(interner, DebruijnIndex::ONE)
+ }
+
+ fn shifted_in_from(self, interner: I, source_binder: DebruijnIndex) -> T {
+ self.try_fold_with(
+ &mut Shifter {
+ source_binder,
+ interner,
+ },
+ DebruijnIndex::INNERMOST,
+ )
+ .unwrap()
+ }
+
+ fn shifted_out_to(self, interner: I, target_binder: DebruijnIndex) -> Fallible<T> {
+ self.try_fold_with(
+ &mut DownShifter {
+ target_binder,
+ interner,
+ },
+ DebruijnIndex::INNERMOST,
+ )
+ }
+
+ fn shifted_out(self, interner: I) -> Fallible<Self> {
+ self.shifted_out_to(interner, DebruijnIndex::ONE)
+ }
+}
+
+/// A folder that adjusts debruijn indices by a certain amount.
+#[derive(FallibleTypeFolder)]
+struct Shifter<I: Interner> {
+ source_binder: DebruijnIndex,
+ interner: I,
+}
+
+impl<I: Interner> Shifter<I> {
+ /// Given a free variable at `depth`, shifts that depth to `depth
+ /// + self.adjustment`, and then wraps *that* within the internal
+ /// set `binders`.
+ fn adjust(&self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> BoundVar {
+ bound_var
+ .shifted_in_from(self.source_binder)
+ .shifted_in_from(outer_binder)
+ }
+}
+
+impl<I: Interner> TypeFolder<I> for Shifter<I> {
+ fn as_dyn(&mut self) -> &mut dyn TypeFolder<I> {
+ self
+ }
+
+ fn fold_free_var_ty(&mut self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> Ty<I> {
+ TyKind::<I>::BoundVar(self.adjust(bound_var, outer_binder))
+ .intern(TypeFolder::interner(self))
+ }
+
+ fn fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ LifetimeData::<I>::BoundVar(self.adjust(bound_var, outer_binder))
+ .intern(TypeFolder::interner(self))
+ }
+
+ fn fold_free_var_const(
+ &mut self,
+ ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ // const types don't have free variables, so we can skip folding `ty`
+ self.adjust(bound_var, outer_binder)
+ .to_const(TypeFolder::interner(self), ty)
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+}
+
+//---------------------------------------------------------------------------
+
+/// A shifter that reduces debruijn indices -- in other words, which lifts a value
+/// *out* from binders. Consider this example:
+///
+struct DownShifter<I> {
+ target_binder: DebruijnIndex,
+ interner: I,
+}
+
+impl<I> DownShifter<I> {
+ /// Given a reference to a free variable at depth `depth`
+ /// (appearing within `binders` internal binders), attempts to
+ /// lift that free variable out from `adjustment` levels of
+ /// binders (i.e., convert it to depth `depth -
+ /// self.adjustment`). If the free variable is bound by one of
+ /// those internal binders (i.e., `depth < self.adjustment`) the
+ /// this will fail with `Err`. Otherwise, returns the variable at
+ /// this new depth (but adjusted to appear within `binders`).
+ fn adjust(&self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> Fallible<BoundVar> {
+ match bound_var.shifted_out_to(self.target_binder) {
+ Some(bound_var1) => Ok(bound_var1.shifted_in_from(outer_binder)),
+ None => Err(NoSolution),
+ }
+ }
+}
+
+impl<I: Interner> FallibleTypeFolder<I> for DownShifter<I> {
+ type Error = NoSolution;
+
+ fn as_dyn(&mut self) -> &mut dyn FallibleTypeFolder<I, Error = Self::Error> {
+ self
+ }
+
+ fn try_fold_free_var_ty(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Fallible<Ty<I>> {
+ Ok(TyKind::<I>::BoundVar(self.adjust(bound_var, outer_binder)?).intern(self.interner()))
+ }
+
+ fn try_fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Fallible<Lifetime<I>> {
+ Ok(
+ LifetimeData::<I>::BoundVar(self.adjust(bound_var, outer_binder)?)
+ .intern(self.interner()),
+ )
+ }
+
+ fn try_fold_free_var_const(
+ &mut self,
+ ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Fallible<Const<I>> {
+ // const types don't have free variables, so we can skip folding `ty`
+ Ok(self
+ .adjust(bound_var, outer_binder)?
+ .to_const(self.interner(), ty))
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+}
diff --git a/vendor/chalk-ir/src/fold/subst.rs b/vendor/chalk-ir/src/fold/subst.rs
new file mode 100644
index 000000000..7cff8d89c
--- /dev/null
+++ b/vendor/chalk-ir/src/fold/subst.rs
@@ -0,0 +1,118 @@
+use super::*;
+use crate::fold::shift::Shift;
+
+/// Substitution used during folding
+#[derive(FallibleTypeFolder)]
+pub struct Subst<'s, I: Interner> {
+ /// Values to substitute. A reference to a free variable with
+ /// index `i` will be mapped to `parameters[i]` -- if `i >
+ /// parameters.len()`, then we will leave the variable untouched.
+ parameters: &'s [GenericArg<I>],
+ interner: I,
+}
+
+impl<I: Interner> Subst<'_, I> {
+ /// Applies the substitution by folding
+ pub fn apply<T: TypeFoldable<I>>(interner: I, parameters: &[GenericArg<I>], value: T) -> T {
+ value
+ .try_fold_with(
+ &mut Subst {
+ parameters,
+ interner,
+ },
+ DebruijnIndex::INNERMOST,
+ )
+ .unwrap()
+ }
+}
+
+impl<I: Interner> TypeFolder<I> for Subst<'_, I> {
+ fn as_dyn(&mut self) -> &mut dyn TypeFolder<I> {
+ self
+ }
+
+ /// We are eliminating one binder, but binders outside of that get preserved.
+ ///
+ /// So e.g. consider this:
+ ///
+ /// ```notrust
+ /// for<A, B> { for<C> { [A, C] } }
+ /// // ^ the binder we are substituing with `[u32]`
+ /// ```
+ ///
+ /// Here, `A` would be `^1.0` and `C` would be `^0.0`. We will replace `^0.0` with the
+ /// 0th index from the list (`u32`). We will convert `^1.0` (A) to `^0.0` -- i.e., shift
+ /// it **out** of one level of binder (the `for<C>` binder we are eliminating).
+ ///
+ /// This gives us as a result:
+ ///
+ /// ```notrust
+ /// for<A, B> { [A, u32] }
+ /// ^ represented as `^0.0`
+ /// ```
+ fn fold_free_var_ty(&mut self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> Ty<I> {
+ if let Some(index) = bound_var.index_if_innermost() {
+ match self.parameters[index].data(TypeFolder::interner(self)) {
+ GenericArgData::Ty(t) => t
+ .clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder),
+ _ => panic!("mismatched kinds in substitution"),
+ }
+ } else {
+ bound_var
+ .shifted_out()
+ .expect("cannot fail because this is not the innermost")
+ .shifted_in_from(outer_binder)
+ .to_ty(TypeFolder::interner(self))
+ }
+ }
+
+ /// see `fold_free_var_ty`
+ fn fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ if let Some(index) = bound_var.index_if_innermost() {
+ match self.parameters[index].data(TypeFolder::interner(self)) {
+ GenericArgData::Lifetime(l) => l
+ .clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder),
+ _ => panic!("mismatched kinds in substitution"),
+ }
+ } else {
+ bound_var
+ .shifted_out()
+ .unwrap()
+ .shifted_in_from(outer_binder)
+ .to_lifetime(TypeFolder::interner(self))
+ }
+ }
+
+ /// see `fold_free_var_ty`
+ fn fold_free_var_const(
+ &mut self,
+ ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ if let Some(index) = bound_var.index_if_innermost() {
+ match self.parameters[index].data(TypeFolder::interner(self)) {
+ GenericArgData::Const(c) => c
+ .clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder),
+ _ => panic!("mismatched kinds in substitution"),
+ }
+ } else {
+ bound_var
+ .shifted_out()
+ .unwrap()
+ .shifted_in_from(outer_binder)
+ .to_const(TypeFolder::interner(self), ty)
+ }
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+}
diff --git a/vendor/chalk-ir/src/interner.rs b/vendor/chalk-ir/src/interner.rs
new file mode 100644
index 000000000..4959e4b74
--- /dev/null
+++ b/vendor/chalk-ir/src/interner.rs
@@ -0,0 +1,702 @@
+//! Encapsulates the concrete representation of core types such as types and goals.
+use crate::AliasTy;
+use crate::AssocTypeId;
+use crate::CanonicalVarKind;
+use crate::CanonicalVarKinds;
+use crate::ClosureId;
+use crate::Constraint;
+use crate::Constraints;
+use crate::FnDefId;
+use crate::ForeignDefId;
+use crate::GeneratorId;
+use crate::GenericArg;
+use crate::GenericArgData;
+use crate::Goal;
+use crate::GoalData;
+use crate::Goals;
+use crate::InEnvironment;
+use crate::Lifetime;
+use crate::LifetimeData;
+use crate::OpaqueTy;
+use crate::OpaqueTyId;
+use crate::ProgramClause;
+use crate::ProgramClauseData;
+use crate::ProgramClauseImplication;
+use crate::ProgramClauses;
+use crate::ProjectionTy;
+use crate::QuantifiedWhereClause;
+use crate::QuantifiedWhereClauses;
+use crate::SeparatorTraitRef;
+use crate::Substitution;
+use crate::TraitId;
+use crate::Ty;
+use crate::TyData;
+use crate::VariableKind;
+use crate::VariableKinds;
+use crate::Variance;
+use crate::Variances;
+use crate::{AdtId, TyKind};
+use crate::{Const, ConstData};
+use std::fmt::{self, Debug};
+use std::hash::Hash;
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+/// A "interner" encapsulates the concrete representation of
+/// certain "core types" from chalk-ir. All the types in chalk-ir are
+/// parameterized by a `I: Interner`, and so (e.g.) if they want to
+/// store a type, they don't store a `Ty<I>` instance directly, but
+/// rather prefer a `Ty<I>`. You can think of `I::Type` as the
+/// interned representation (and, indeed, it may well be an interned
+/// pointer, e.g. in rustc).
+///
+/// Type families allow chalk to be embedded in different contexts
+/// where the concrete representation of core types varies. They also
+/// allow us to write generic code that reasons about multiple
+/// distinct sets of types by using distinct generic type parameters
+/// (e.g., `SourceI` and `TargetI`) -- even if those type parameters
+/// wind up being mapped to the same underlying type families in the
+/// end.
+pub trait Interner: Debug + Copy + Eq + Hash + Sized {
+ /// "Interned" representation of types. In normal user code,
+ /// `Self::InternedType` is not referenced. Instead, we refer to
+ /// `Ty<Self>`, which wraps this type.
+ ///
+ /// An `InternedType` must be something that can be created from a
+ /// `TyKind` (by the [`intern_ty`][Self::intern_ty] method) and then later
+ /// converted back (by the [`ty_data`][Self::ty_data] method). The interned form
+ /// must also introduce indirection, either via a `Box`, `&`, or
+ /// other pointer type.
+ type InternedType: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of lifetimes. In normal user code,
+ /// `Self::InternedLifetime` is not referenced. Instead, we refer to
+ /// `Lifetime<Self>`, which wraps this type.
+ ///
+ /// An `InternedLifetime` must be something that can be created
+ /// from a `LifetimeData` (by the [`intern_lifetime`][Self::intern_lifetime] method) and
+ /// then later converted back (by the [`lifetime_data`][Self::lifetime_data] method).
+ type InternedLifetime: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of const expressions. In normal user code,
+ /// `Self::InternedConst` is not referenced. Instead, we refer to
+ /// `Const<Self>`, which wraps this type.
+ ///
+ /// An `InternedConst` must be something that can be created
+ /// from a `ConstData` (by the [`intern_const`][Self::intern_const] method) and
+ /// then later converted back (by the [`const_data`][Self::const_data] method).
+ type InternedConst: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of an evaluated const value.
+ /// `Self::InternedConcreteConst` is not referenced. Instead,
+ /// we refer to `ConcreteConst<Self>`, which wraps this type.
+ ///
+ /// `InternedConcreteConst` instances are not created by chalk,
+ /// it can only make a query asking about equality of two
+ /// evaluated consts.
+ type InternedConcreteConst: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a "generic parameter", which can
+ /// be either a type or a lifetime. In normal user code,
+ /// `Self::InternedGenericArg` is not referenced. Instead, we refer to
+ /// `GenericArg<Self>`, which wraps this type.
+ ///
+ /// An `InternedType` is created by `intern_generic_arg` and can be
+ /// converted back to its underlying data via `generic_arg_data`.
+ type InternedGenericArg: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a "goal". In normal user code,
+ /// `Self::InternedGoal` is not referenced. Instead, we refer to
+ /// `Goal<Self>`, which wraps this type.
+ ///
+ /// An `InternedGoal` is created by `intern_goal` and can be
+ /// converted back to its underlying data via `goal_data`.
+ type InternedGoal: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of goals. In normal user code,
+ /// `Self::InternedGoals` is not referenced. Instead, we refer to
+ /// `Goals<Self>`, which wraps this type.
+ ///
+ /// An `InternedGoals` is created by `intern_goals` and can be
+ /// converted back to its underlying data via `goals_data`.
+ type InternedGoals: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a "substitution". In normal user code,
+ /// `Self::InternedSubstitution` is not referenced. Instead, we refer to
+ /// `Substitution<Self>`, which wraps this type.
+ ///
+ /// An `InternedSubstitution` is created by `intern_substitution` and can be
+ /// converted back to its underlying data via `substitution_data`.
+ type InternedSubstitution: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of program clauses. In normal user code,
+ /// `Self::InternedProgramClauses` is not referenced. Instead, we refer to
+ /// `ProgramClauses<Self>`, which wraps this type.
+ ///
+ /// An `InternedProgramClauses` is created by `intern_program_clauses` and can be
+ /// converted back to its underlying data via `program_clauses_data`.
+ type InternedProgramClauses: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a "program clause". In normal user code,
+ /// `Self::InternedProgramClause` is not referenced. Instead, we refer to
+ /// `ProgramClause<Self>`, which wraps this type.
+ ///
+ /// An `InternedProgramClause` is created by `intern_program_clause` and can be
+ /// converted back to its underlying data via `program_clause_data`.
+ type InternedProgramClause: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of quantified where clauses.
+ /// In normal user code, `Self::InternedQuantifiedWhereClauses` is not referenced.
+ /// Instead, we refer to `QuantifiedWhereClauses<Self>`, which wraps this type.
+ ///
+ /// An `InternedQuantifiedWhereClauses` is created by `intern_quantified_where_clauses`
+ /// and can be converted back to its underlying data via `quantified_where_clauses_data`.
+ type InternedQuantifiedWhereClauses: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of variable kinds.
+ /// In normal user code, `Self::InternedVariableKinds` is not referenced.
+ /// Instead, we refer to `VariableKinds<Self>`, which wraps this type.
+ ///
+ /// An `InternedVariableKinds` is created by `intern_generic_arg_kinds`
+ /// and can be converted back to its underlying data via `variable_kinds_data`.
+ type InternedVariableKinds: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of variable kinds with universe index.
+ /// In normal user code, `Self::InternedCanonicalVarKinds` is not referenced.
+ /// Instead, we refer to `CanonicalVarKinds<Self>`, which wraps this type.
+ ///
+ /// An `InternedCanonicalVarKinds` is created by
+ /// `intern_canonical_var_kinds` and can be converted back
+ /// to its underlying data via `canonical_var_kinds_data`.
+ type InternedCanonicalVarKinds: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of region constraints.
+ /// In normal user code, `Self::InternedConstraints` is not referenced.
+ /// Instead, we refer to `Constraints<Self>`, which wraps this type.
+ ///
+ /// An `InternedConstraints` is created by `intern_constraints`
+ /// and can be converted back to its underlying data via `constraints_data`.
+ type InternedConstraints: Debug + Clone + Eq + Hash;
+
+ /// "Interned" representation of a list of `chalk_ir::Variance`.
+ /// In normal user code, `Self::InternedVariances` is not referenced.
+ /// Instead, we refer to `Variances<Self>`, which wraps this type.
+ ///
+ /// An `InternedVariances` is created by
+ /// `intern_variances` and can be converted back
+ /// to its underlying data via `variances_data`.
+ type InternedVariances: Debug + Clone + Eq + Hash;
+
+ /// The core "id" type used for trait-ids and the like.
+ type DefId: Debug + Copy + Eq + Hash;
+
+ /// The ID type for ADTs
+ type InternedAdtId: Debug + Copy + Eq + Hash;
+
+ /// Representation of identifiers.
+ type Identifier: Debug + Clone + Eq + Hash;
+
+ /// Representation of function ABI (e.g. calling convention).
+ type FnAbi: Debug + Copy + Eq + Hash;
+
+ /// Prints the debug representation of a type-kind-id.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_adt_id(adt_id: AdtId<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a type-kind-id.
+ /// Returns `None` to fallback to the default debug output (e.g.,
+ /// if no info about current program is available from TLS).
+ #[allow(unused_variables)]
+ fn debug_trait_id(
+ trait_id: TraitId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a type-kind-id.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_assoc_type_id(
+ type_id: AssocTypeId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an opaque type.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_opaque_ty_id(
+ opaque_ty_id: OpaqueTyId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a function-def-id.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_fn_def_id(
+ fn_def_id: FnDefId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a closure id.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_closure_id(
+ fn_def_id: ClosureId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a foreign-def-id.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_foreign_def_id(
+ foreign_def_id: ForeignDefId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an alias.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_generator_id(
+ generator_id: GeneratorId<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an alias. To get good
+ /// results, this requires inspecting TLS, and is difficult to
+ /// code without reference to a specific interner (and hence
+ /// fully known types).
+ ///
+ /// Returns `None` to fallback to the default debug output (e.g.,
+ /// if no info about current program is available from TLS).
+ #[allow(unused_variables)]
+ fn debug_alias(alias: &AliasTy<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a ProjectionTy.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_projection_ty(
+ projection_ty: &ProjectionTy<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an OpaqueTy.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_opaque_ty(
+ opaque_ty: &OpaqueTy<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a type.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_ty(ty: &Ty<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a lifetime.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_lifetime(
+ lifetime: &Lifetime<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a const.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_const(constant: &Const<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an parameter.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_generic_arg(
+ generic_arg: &GenericArg<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a parameter kinds list.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_variable_kinds(
+ variable_kinds: &VariableKinds<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a parameter kinds list, with angle brackets.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_variable_kinds_with_angles(
+ variable_kinds: &VariableKinds<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an parameter kinds list with universe index.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_canonical_var_kinds(
+ canonical_var_kinds: &CanonicalVarKinds<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of an goal.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_goal(goal: &Goal<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a list of goals.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_goals(goals: &Goals<Self>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a ProgramClauseImplication.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_program_clause_implication(
+ pci: &ProgramClauseImplication<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a ProgramClause.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_program_clause(
+ clause: &ProgramClause<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a ProgramClauses.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_program_clauses(
+ clauses: &ProgramClauses<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a Substitution.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_substitution(
+ substitution: &Substitution<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a SeparatorTraitRef.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_separator_trait_ref(
+ separator_trait_ref: &SeparatorTraitRef<'_, Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a QuantifiedWhereClauses.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_quantified_where_clauses(
+ clauses: &QuantifiedWhereClauses<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a Constraints.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_constraints(
+ clauses: &Constraints<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Prints the debug representation of a Variances.
+ /// Returns `None` to fallback to the default debug output.
+ #[allow(unused_variables)]
+ fn debug_variances(
+ variances: &Variances<Self>,
+ fmt: &mut fmt::Formatter<'_>,
+ ) -> Option<fmt::Result> {
+ None
+ }
+
+ /// Create an "interned" type from `ty`. This is not normally
+ /// invoked directly; instead, you invoke `TyKind::intern` (which
+ /// will ultimately call this method).
+ fn intern_ty(self, kind: TyKind<Self>) -> Self::InternedType;
+
+ /// Lookup the `TyKind` from an interned type.
+ fn ty_data(self, ty: &Self::InternedType) -> &TyData<Self>;
+
+ /// Create an "interned" lifetime from `lifetime`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `LifetimeData::intern` (which will ultimately call this
+ /// method).
+ fn intern_lifetime(self, lifetime: LifetimeData<Self>) -> Self::InternedLifetime;
+
+ /// Lookup the `LifetimeData` that was interned to create a `InternedLifetime`.
+ fn lifetime_data(self, lifetime: &Self::InternedLifetime) -> &LifetimeData<Self>;
+
+ /// Create an "interned" const from `const`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `ConstData::intern` (which will ultimately call this
+ /// method).
+ fn intern_const(self, constant: ConstData<Self>) -> Self::InternedConst;
+
+ /// Lookup the `ConstData` that was interned to create a `InternedConst`.
+ fn const_data(self, constant: &Self::InternedConst) -> &ConstData<Self>;
+
+ /// Determine whether two concrete const values are equal.
+ fn const_eq(
+ self,
+ ty: &Self::InternedType,
+ c1: &Self::InternedConcreteConst,
+ c2: &Self::InternedConcreteConst,
+ ) -> bool;
+
+ /// Create an "interned" parameter from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `GenericArgData::intern` (which will ultimately call this
+ /// method).
+ fn intern_generic_arg(self, data: GenericArgData<Self>) -> Self::InternedGenericArg;
+
+ /// Lookup the `LifetimeData` that was interned to create a `InternedLifetime`.
+ fn generic_arg_data(self, lifetime: &Self::InternedGenericArg) -> &GenericArgData<Self>;
+
+ /// Create an "interned" goal from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `GoalData::intern` (which will ultimately call this
+ /// method).
+ fn intern_goal(self, data: GoalData<Self>) -> Self::InternedGoal;
+
+ /// Lookup the `GoalData` that was interned to create a `InternedGoal`.
+ fn goal_data(self, goal: &Self::InternedGoal) -> &GoalData<Self>;
+
+ /// Create an "interned" goals from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `GoalsData::intern` (which will ultimately call this
+ /// method).
+ fn intern_goals<E>(
+ self,
+ data: impl IntoIterator<Item = Result<Goal<Self>, E>>,
+ ) -> Result<Self::InternedGoals, E>;
+
+ /// Lookup the `GoalsData` that was interned to create a `InternedGoals`.
+ fn goals_data(self, goals: &Self::InternedGoals) -> &[Goal<Self>];
+
+ /// Create an "interned" substitution from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `SubstitutionData::intern` (which will ultimately call this
+ /// method).
+ fn intern_substitution<E>(
+ self,
+ data: impl IntoIterator<Item = Result<GenericArg<Self>, E>>,
+ ) -> Result<Self::InternedSubstitution, E>;
+
+ /// Lookup the `SubstitutionData` that was interned to create a `InternedSubstitution`.
+ fn substitution_data(self, substitution: &Self::InternedSubstitution) -> &[GenericArg<Self>];
+
+ /// Create an "interned" program clause from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `ProgramClauseData::intern` (which will ultimately call this
+ /// method).
+ fn intern_program_clause(self, data: ProgramClauseData<Self>) -> Self::InternedProgramClause;
+
+ /// Lookup the `ProgramClauseData` that was interned to create a `ProgramClause`.
+ fn program_clause_data(self, clause: &Self::InternedProgramClause) -> &ProgramClauseData<Self>;
+
+ /// Create an "interned" program clauses from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `ProgramClauses::from_iter` (which will ultimately call this
+ /// method).
+ fn intern_program_clauses<E>(
+ self,
+ data: impl IntoIterator<Item = Result<ProgramClause<Self>, E>>,
+ ) -> Result<Self::InternedProgramClauses, E>;
+
+ /// Lookup the `ProgramClauseData` that was interned to create a `ProgramClause`.
+ fn program_clauses_data(self, clauses: &Self::InternedProgramClauses)
+ -> &[ProgramClause<Self>];
+
+ /// Create an "interned" quantified where clauses from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `QuantifiedWhereClauses::from_iter` (which will ultimately call this
+ /// method).
+ fn intern_quantified_where_clauses<E>(
+ self,
+ data: impl IntoIterator<Item = Result<QuantifiedWhereClause<Self>, E>>,
+ ) -> Result<Self::InternedQuantifiedWhereClauses, E>;
+
+ /// Lookup the slice of `QuantifiedWhereClause` that was interned to
+ /// create a `QuantifiedWhereClauses`.
+ fn quantified_where_clauses_data(
+ self,
+ clauses: &Self::InternedQuantifiedWhereClauses,
+ ) -> &[QuantifiedWhereClause<Self>];
+
+ /// Create an "interned" parameter kinds from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `VariableKinds::from_iter` (which will ultimately call this
+ /// method).
+ fn intern_generic_arg_kinds<E>(
+ self,
+ data: impl IntoIterator<Item = Result<VariableKind<Self>, E>>,
+ ) -> Result<Self::InternedVariableKinds, E>;
+
+ /// Lookup the slice of `VariableKinds` that was interned to
+ /// create a `VariableKinds`.
+ fn variable_kinds_data(
+ self,
+ variable_kinds: &Self::InternedVariableKinds,
+ ) -> &[VariableKind<Self>];
+
+ /// Create "interned" variable kinds with universe index from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `CanonicalVarKinds::from_iter` (which will ultimately call this
+ /// method).
+ fn intern_canonical_var_kinds<E>(
+ self,
+ data: impl IntoIterator<Item = Result<CanonicalVarKind<Self>, E>>,
+ ) -> Result<Self::InternedCanonicalVarKinds, E>;
+
+ /// Lookup the slice of `CanonicalVariableKind` that was interned to
+ /// create a `CanonicalVariableKinds`.
+ fn canonical_var_kinds_data(
+ self,
+ canonical_var_kinds: &Self::InternedCanonicalVarKinds,
+ ) -> &[CanonicalVarKind<Self>];
+
+ /// Create "interned" constraints from `data`. This is not
+ /// normally invoked dirctly; instead, you invoke
+ /// `Constraints::from_iter` (which will ultimately call this
+ /// method).
+ fn intern_constraints<E>(
+ self,
+ data: impl IntoIterator<Item = Result<InEnvironment<Constraint<Self>>, E>>,
+ ) -> Result<Self::InternedConstraints, E>;
+
+ /// Lookup the slice of `Constraint` that was interned to
+ /// create a `Constraints`.
+ fn constraints_data(
+ self,
+ constraints: &Self::InternedConstraints,
+ ) -> &[InEnvironment<Constraint<Self>>];
+
+ /// Create "interned" variances from `data`. This is not
+ /// normally invoked directly; instead, you invoke
+ /// `Variances::from` (which will ultimately call this
+ /// method).
+ fn intern_variances<E>(
+ self,
+ data: impl IntoIterator<Item = Result<Variance, E>>,
+ ) -> Result<Self::InternedVariances, E>;
+
+ /// Lookup the slice of `Variance` that was interned to
+ /// create a `Variances`.
+ fn variances_data(self, variances: &Self::InternedVariances) -> &[Variance];
+}
+
+/// Implemented by types that have an associated interner (which
+/// are virtually all of the types in chalk-ir, for example).
+/// This lets us map from a type like `Ty<I>` to the parameter `I`.
+///
+/// It's particularly useful for writing `TypeFoldable` impls for generic types like
+/// `Binder<T>`, since it allows us to figure out the interner of `T`.
+pub trait HasInterner {
+ /// The interner associated with the type.
+ type Interner: Interner;
+}
+
+impl<T: HasInterner> HasInterner for [T] {
+ type Interner = T::Interner;
+}
+
+impl<T: HasInterner> HasInterner for Vec<T> {
+ type Interner = T::Interner;
+}
+
+impl<T: HasInterner> HasInterner for Box<T> {
+ type Interner = T::Interner;
+}
+
+impl<T: HasInterner> HasInterner for Arc<T> {
+ type Interner = T::Interner;
+}
+
+impl<T: HasInterner + ?Sized> HasInterner for &T {
+ type Interner = T::Interner;
+}
+
+impl<I: Interner> HasInterner for PhantomData<I> {
+ type Interner = I;
+}
+
+impl<A, B, I> HasInterner for (A, B)
+where
+ A: HasInterner<Interner = I>,
+ B: HasInterner<Interner = I>,
+ I: Interner,
+{
+ type Interner = I;
+}
+
+impl<A, B, C, I> HasInterner for (A, B, C)
+where
+ A: HasInterner<Interner = I>,
+ B: HasInterner<Interner = I>,
+ C: HasInterner<Interner = I>,
+ I: Interner,
+{
+ type Interner = I;
+}
+
+impl<'a, T: HasInterner> HasInterner for std::slice::Iter<'a, T> {
+ type Interner = T::Interner;
+}
diff --git a/vendor/chalk-ir/src/lib.rs b/vendor/chalk-ir/src/lib.rs
new file mode 100644
index 000000000..5cf44b0c3
--- /dev/null
+++ b/vendor/chalk-ir/src/lib.rs
@@ -0,0 +1,3055 @@
+//! Defines the IR for types and logical predicates.
+
+#![deny(rust_2018_idioms)]
+#![warn(missing_docs)]
+
+// Allows macros to refer to this crate as `::chalk_ir`
+extern crate self as chalk_ir;
+
+use crate::cast::{Cast, CastTo, Caster};
+use crate::fold::shift::Shift;
+use crate::fold::{FallibleTypeFolder, Subst, TypeFoldable, TypeFolder, TypeSuperFoldable};
+use crate::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor, VisitExt};
+use chalk_derive::{
+ FallibleTypeFolder, HasInterner, TypeFoldable, TypeSuperVisitable, TypeVisitable, Zip,
+};
+use std::marker::PhantomData;
+use std::ops::ControlFlow;
+
+pub use crate::debug::SeparatorTraitRef;
+#[macro_use(bitflags)]
+extern crate bitflags;
+/// Uninhabited (empty) type, used in combination with `PhantomData`.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum Void {}
+
+/// Many of our internal operations (e.g., unification) are an attempt
+/// to perform some operation which may not complete.
+pub type Fallible<T> = Result<T, NoSolution>;
+
+/// A combination of `Fallible` and `Floundered`.
+pub enum FallibleOrFloundered<T> {
+ /// Success
+ Ok(T),
+ /// No solution. See `chalk_ir::NoSolution`.
+ NoSolution,
+ /// Floundered. See `chalk_ir::Floundered`.
+ Floundered,
+}
+
+/// Indicates that the attempted operation has "no solution" -- i.e.,
+/// cannot be performed.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct NoSolution;
+
+/// Indicates that the complete set of program clauses for this goal
+/// cannot be enumerated.
+pub struct Floundered;
+
+macro_rules! impl_debugs {
+ ($($id:ident), *) => {
+ $(
+ impl<I: Interner> std::fmt::Debug for $id<I> {
+ fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+ write!(fmt, "{}({:?})", stringify!($id), self.0)
+ }
+ }
+ )*
+ };
+}
+
+#[macro_use]
+pub mod zip;
+
+#[macro_use]
+pub mod fold;
+
+#[macro_use]
+pub mod visit;
+
+pub mod cast;
+
+pub mod interner;
+use interner::{HasInterner, Interner};
+
+pub mod could_match;
+pub mod debug;
+
+/// Variance
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Variance {
+ /// a <: b
+ Covariant,
+ /// a == b
+ Invariant,
+ /// b <: a
+ Contravariant,
+}
+
+impl Variance {
+ /// `a.xform(b)` combines the variance of a context with the
+ /// variance of a type with the following meaning. If we are in a
+ /// context with variance `a`, and we encounter a type argument in
+ /// a position with variance `b`, then `a.xform(b)` is the new
+ /// variance with which the argument appears.
+ ///
+ /// Example 1:
+ ///
+ /// ```ignore
+ /// *mut Vec<i32>
+ /// ```
+ ///
+ /// Here, the "ambient" variance starts as covariant. `*mut T` is
+ /// invariant with respect to `T`, so the variance in which the
+ /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
+ /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
+ /// respect to its type argument `T`, and hence the variance of
+ /// the `i32` here is `Invariant.xform(Covariant)`, which results
+ /// (again) in `Invariant`.
+ ///
+ /// Example 2:
+ ///
+ /// ```ignore
+ /// fn(*const Vec<i32>, *mut Vec<i32)
+ /// ```
+ ///
+ /// The ambient variance is covariant. A `fn` type is
+ /// contravariant with respect to its parameters, so the variance
+ /// within which both pointer types appear is
+ /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
+ /// T` is covariant with respect to `T`, so the variance within
+ /// which the first `Vec<i32>` appears is
+ /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
+ /// is true for its `i32` argument. In the `*mut T` case, the
+ /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
+ /// and hence the outermost type is `Invariant` with respect to
+ /// `Vec<i32>` (and its `i32` argument).
+ ///
+ /// Source: Figure 1 of "Taming the Wildcards:
+ /// Combining Definition- and Use-Site Variance" published in PLDI'11.
+ /// (Doc from rustc)
+ pub fn xform(self, other: Variance) -> Variance {
+ match (self, other) {
+ (Variance::Invariant, _) => Variance::Invariant,
+ (_, Variance::Invariant) => Variance::Invariant,
+ (_, Variance::Covariant) => self,
+ (Variance::Covariant, Variance::Contravariant) => Variance::Contravariant,
+ (Variance::Contravariant, Variance::Contravariant) => Variance::Covariant,
+ }
+ }
+
+ /// Converts `Covariant` into `Contravariant` and vice-versa. `Invariant`
+ /// stays the same.
+ pub fn invert(self) -> Variance {
+ match self {
+ Variance::Invariant => Variance::Invariant,
+ Variance::Covariant => Variance::Contravariant,
+ Variance::Contravariant => Variance::Covariant,
+ }
+ }
+}
+
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+/// The set of assumptions we've made so far, and the current number of
+/// universal (forall) quantifiers we're within.
+pub struct Environment<I: Interner> {
+ /// The clauses in the environment.
+ pub clauses: ProgramClauses<I>,
+}
+
+impl<I: Interner> Copy for Environment<I> where I::InternedProgramClauses: Copy {}
+
+impl<I: Interner> Environment<I> {
+ /// Creates a new environment.
+ pub fn new(interner: I) -> Self {
+ Environment {
+ clauses: ProgramClauses::empty(interner),
+ }
+ }
+
+ /// Adds (an iterator of) clauses to the environment.
+ pub fn add_clauses<II>(&self, interner: I, clauses: II) -> Self
+ where
+ II: IntoIterator<Item = ProgramClause<I>>,
+ {
+ let mut env = self.clone();
+ env.clauses =
+ ProgramClauses::from_iter(interner, env.clauses.iter(interner).cloned().chain(clauses));
+ env
+ }
+
+ /// True if any of the clauses in the environment have a consequence of `Compatible`.
+ /// Panics if the conditions or constraints of that clause are not empty.
+ pub fn has_compatible_clause(&self, interner: I) -> bool {
+ self.clauses.as_slice(interner).iter().any(|c| {
+ let ProgramClauseData(implication) = c.data(interner);
+ match implication.skip_binders().consequence {
+ DomainGoal::Compatible => {
+ // We currently don't generate `Compatible` with any conditions or constraints
+ // If this was needed, for whatever reason, then a third "yes, but must evaluate"
+ // return value would have to be added.
+ assert!(implication.skip_binders().conditions.is_empty(interner));
+ assert!(implication.skip_binders().constraints.is_empty(interner));
+ true
+ }
+ _ => false,
+ }
+ })
+ }
+}
+
+/// A goal with an environment to solve it in.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
+#[allow(missing_docs)]
+pub struct InEnvironment<G: HasInterner> {
+ pub environment: Environment<G::Interner>,
+ pub goal: G,
+}
+
+impl<G: HasInterner<Interner = I> + Copy, I: Interner> Copy for InEnvironment<G> where
+ I::InternedProgramClauses: Copy
+{
+}
+
+impl<G: HasInterner> InEnvironment<G> {
+ /// Creates a new environment/goal pair.
+ pub fn new(environment: &Environment<G::Interner>, goal: G) -> Self {
+ InEnvironment {
+ environment: environment.clone(),
+ goal,
+ }
+ }
+
+ /// Maps the goal without touching the environment.
+ pub fn map<OP, H>(self, op: OP) -> InEnvironment<H>
+ where
+ OP: FnOnce(G) -> H,
+ H: HasInterner<Interner = G::Interner>,
+ {
+ InEnvironment {
+ environment: self.environment,
+ goal: op(self.goal),
+ }
+ }
+}
+
+impl<G: HasInterner> HasInterner for InEnvironment<G> {
+ type Interner = G::Interner;
+}
+
+/// Different signed int types.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[allow(missing_docs)]
+pub enum IntTy {
+ Isize,
+ I8,
+ I16,
+ I32,
+ I64,
+ I128,
+}
+
+/// Different unsigned int types.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[allow(missing_docs)]
+pub enum UintTy {
+ Usize,
+ U8,
+ U16,
+ U32,
+ U64,
+ U128,
+}
+
+/// Different kinds of float types.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[allow(missing_docs)]
+pub enum FloatTy {
+ F32,
+ F64,
+}
+
+/// Types of scalar values.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[allow(missing_docs)]
+pub enum Scalar {
+ Bool,
+ Char,
+ Int(IntTy),
+ Uint(UintTy),
+ Float(FloatTy),
+}
+
+/// Whether a function is safe or not.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum Safety {
+ /// Safe
+ Safe,
+ /// Unsafe
+ Unsafe,
+}
+
+/// Whether a type is mutable or not.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum Mutability {
+ /// Mutable
+ Mut,
+ /// Immutable
+ Not,
+}
+
+/// An universe index is how a universally quantified parameter is
+/// represented when it's binder is moved into the environment.
+/// An example chain of transformations would be:
+/// `forall<T> { Goal(T) }` (syntactical representation)
+/// `forall { Goal(?0) }` (used a DeBruijn index)
+/// `Goal(!U1)` (the quantifier was moved to the environment and replaced with a universe index)
+/// See <https://rustc-dev-guide.rust-lang.org/borrow_check/region_inference.html#placeholders-and-universes> for more.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct UniverseIndex {
+ /// The counter for the universe index, starts with 0.
+ pub counter: usize,
+}
+
+impl UniverseIndex {
+ /// Root universe index (0).
+ pub const ROOT: UniverseIndex = UniverseIndex { counter: 0 };
+
+ /// Root universe index (0).
+ pub fn root() -> UniverseIndex {
+ Self::ROOT
+ }
+
+ /// Whether one universe can "see" another.
+ pub fn can_see(self, ui: UniverseIndex) -> bool {
+ self.counter >= ui.counter
+ }
+
+ /// Increases the index counter.
+ pub fn next(self) -> UniverseIndex {
+ UniverseIndex {
+ counter: self.counter + 1,
+ }
+ }
+}
+
+/// Maps the universes found in the `u_canonicalize` result (the
+/// "canonical" universes) to the universes found in the original
+/// value (and vice versa). When used as a folder -- i.e., from
+/// outside this module -- converts from "canonical" universes to the
+/// original (but see the `UMapToCanonical` folder).
+#[derive(Clone, Debug)]
+pub struct UniverseMap {
+ /// A reverse map -- for each universe Ux that appears in
+ /// `quantified`, the corresponding universe in the original was
+ /// `universes[x]`.
+ pub universes: Vec<UniverseIndex>,
+}
+
+impl UniverseMap {
+ /// Creates a new universe map.
+ pub fn new() -> Self {
+ UniverseMap {
+ universes: vec![UniverseIndex::root()],
+ }
+ }
+
+ /// Number of canonical universes.
+ pub fn num_canonical_universes(&self) -> usize {
+ self.universes.len()
+ }
+}
+
+/// The id for an Abstract Data Type (i.e. structs, unions and enums).
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct AdtId<I: Interner>(pub I::InternedAdtId);
+
+/// The id of a trait definition; could be used to load the trait datum by
+/// invoking the [`trait_datum`] method.
+///
+/// [`trait_datum`]: ../chalk_solve/trait.RustIrDatabase.html#tymethod.trait_datum
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct TraitId<I: Interner>(pub I::DefId);
+
+/// The id for an impl.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ImplId<I: Interner>(pub I::DefId);
+
+/// Id for a specific clause.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ClauseId<I: Interner>(pub I::DefId);
+
+/// The id for the associated type member of a trait. The details of the type
+/// can be found by invoking the [`associated_ty_data`] method.
+///
+/// [`associated_ty_data`]: ../chalk_solve/trait.RustIrDatabase.html#tymethod.associated_ty_data
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct AssocTypeId<I: Interner>(pub I::DefId);
+
+/// Id for an opaque type.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct OpaqueTyId<I: Interner>(pub I::DefId);
+
+/// Function definition id.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct FnDefId<I: Interner>(pub I::DefId);
+
+/// Id for Rust closures.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ClosureId<I: Interner>(pub I::DefId);
+
+/// Id for Rust generators.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct GeneratorId<I: Interner>(pub I::DefId);
+
+/// Id for foreign types.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ForeignDefId<I: Interner>(pub I::DefId);
+
+impl_debugs!(ImplId, ClauseId);
+
+/// A Rust type. The actual type data is stored in `TyKind`.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct Ty<I: Interner> {
+ interned: I::InternedType,
+}
+
+impl<I: Interner> Ty<I> {
+ /// Creates a type from `TyKind`.
+ pub fn new(interner: I, data: impl CastTo<TyKind<I>>) -> Self {
+ let ty_kind = data.cast(interner);
+ Ty {
+ interned: I::intern_ty(interner, ty_kind),
+ }
+ }
+
+ /// Gets the interned type.
+ pub fn interned(&self) -> &I::InternedType {
+ &self.interned
+ }
+
+ /// Gets the underlying type data.
+ pub fn data(&self, interner: I) -> &TyData<I> {
+ I::ty_data(interner, &self.interned)
+ }
+
+ /// Gets the underlying type kind.
+ pub fn kind(&self, interner: I) -> &TyKind<I> {
+ &I::ty_data(interner, &self.interned).kind
+ }
+
+ /// Creates a `FromEnv` constraint using this type.
+ pub fn from_env(&self) -> FromEnv<I> {
+ FromEnv::Ty(self.clone())
+ }
+
+ /// Creates a WF-constraint for this type.
+ pub fn well_formed(&self) -> WellFormed<I> {
+ WellFormed::Ty(self.clone())
+ }
+
+ /// Creates a domain goal `FromEnv(T)` where `T` is this type.
+ pub fn into_from_env_goal(self, interner: I) -> DomainGoal<I> {
+ self.from_env().cast(interner)
+ }
+
+ /// If this is a `TyKind::BoundVar(d)`, returns `Some(d)` else `None`.
+ pub fn bound_var(&self, interner: I) -> Option<BoundVar> {
+ if let TyKind::BoundVar(bv) = self.kind(interner) {
+ Some(*bv)
+ } else {
+ None
+ }
+ }
+
+ /// If this is a `TyKind::InferenceVar(d)`, returns `Some(d)` else `None`.
+ pub fn inference_var(&self, interner: I) -> Option<InferenceVar> {
+ if let TyKind::InferenceVar(depth, _) = self.kind(interner) {
+ Some(*depth)
+ } else {
+ None
+ }
+ }
+
+ /// Returns true if this is a `BoundVar` or an `InferenceVar` of `TyVariableKind::General`.
+ pub fn is_general_var(&self, interner: I, binders: &CanonicalVarKinds<I>) -> bool {
+ match self.kind(interner) {
+ TyKind::BoundVar(bv)
+ if bv.debruijn == DebruijnIndex::INNERMOST
+ && binders.at(interner, bv.index).kind
+ == VariableKind::Ty(TyVariableKind::General) =>
+ {
+ true
+ }
+ TyKind::InferenceVar(_, TyVariableKind::General) => true,
+ _ => false,
+ }
+ }
+
+ /// Returns true if this is an `Alias`.
+ pub fn is_alias(&self, interner: I) -> bool {
+ matches!(self.kind(interner), TyKind::Alias(..))
+ }
+
+ /// Returns true if this is an `IntTy` or `UintTy`.
+ pub fn is_integer(&self, interner: I) -> bool {
+ matches!(
+ self.kind(interner),
+ TyKind::Scalar(Scalar::Int(_) | Scalar::Uint(_))
+ )
+ }
+
+ /// Returns true if this is a `FloatTy`.
+ pub fn is_float(&self, interner: I) -> bool {
+ matches!(self.kind(interner), TyKind::Scalar(Scalar::Float(_)))
+ }
+
+ /// Returns `Some(adt_id)` if this is an ADT, `None` otherwise
+ pub fn adt_id(&self, interner: I) -> Option<AdtId<I>> {
+ match self.kind(interner) {
+ TyKind::Adt(adt_id, _) => Some(*adt_id),
+ _ => None,
+ }
+ }
+
+ /// True if this type contains "bound" types/lifetimes, and hence
+ /// needs to be shifted across binders. This is a very inefficient
+ /// check, intended only for debug assertions, because I am lazy.
+ pub fn needs_shift(&self, interner: I) -> bool {
+ self.has_free_vars(interner)
+ }
+}
+
+/// Contains the data for a Ty
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner)]
+pub struct TyData<I: Interner> {
+ /// The kind
+ pub kind: TyKind<I>,
+ /// Type flags
+ pub flags: TypeFlags,
+}
+
+bitflags! {
+ /// Contains flags indicating various properties of a Ty
+ pub struct TypeFlags : u16 {
+ /// Does the type contain an InferenceVar
+ const HAS_TY_INFER = 1;
+ /// Does the type contain a lifetime with an InferenceVar
+ const HAS_RE_INFER = 1 << 1;
+ /// Does the type contain a ConstValue with an InferenceVar
+ const HAS_CT_INFER = 1 << 2;
+ /// Does the type contain a Placeholder TyKind
+ const HAS_TY_PLACEHOLDER = 1 << 3;
+ /// Does the type contain a lifetime with a Placeholder
+ const HAS_RE_PLACEHOLDER = 1 << 4;
+ /// Does the type contain a ConstValue Placeholder
+ const HAS_CT_PLACEHOLDER = 1 << 5;
+ /// True when the type has free lifetimes related to a local context
+ const HAS_FREE_LOCAL_REGIONS = 1 << 6;
+ /// Does the type contain a projection of an associated type
+ const HAS_TY_PROJECTION = 1 << 7;
+ /// Does the type contain an opaque type
+ const HAS_TY_OPAQUE = 1 << 8;
+ /// Does the type contain an unevaluated const projection
+ const HAS_CT_PROJECTION = 1 << 9;
+ /// Does the type contain an error
+ const HAS_ERROR = 1 << 10;
+ /// Does the type contain any free lifetimes
+ const HAS_FREE_REGIONS = 1 << 11;
+ /// True when the type contains lifetimes that will be substituted when function is called
+ const HAS_RE_LATE_BOUND = 1 << 12;
+ /// True when the type contains an erased lifetime
+ const HAS_RE_ERASED = 1 << 13;
+ /// Does the type contain placeholders or inference variables that could be replaced later
+ const STILL_FURTHER_SPECIALIZABLE = 1 << 14;
+
+ /// True when the type contains free names local to a particular context
+ const HAS_FREE_LOCAL_NAMES = TypeFlags::HAS_TY_INFER.bits
+ | TypeFlags::HAS_CT_INFER.bits
+ | TypeFlags::HAS_TY_PLACEHOLDER.bits
+ | TypeFlags::HAS_CT_PLACEHOLDER.bits
+ | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits;
+
+ /// Does the type contain any form of projection
+ const HAS_PROJECTION = TypeFlags::HAS_TY_PROJECTION.bits
+ | TypeFlags::HAS_TY_OPAQUE.bits
+ | TypeFlags::HAS_CT_PROJECTION.bits;
+ }
+}
+/// Type data, which holds the actual type information.
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner)]
+pub enum TyKind<I: Interner> {
+ /// Abstract data types, i.e., structs, unions, or enumerations.
+ /// For example, a type like `Vec<T>`.
+ Adt(AdtId<I>, Substitution<I>),
+
+ /// an associated type like `Iterator::Item`; see `AssociatedType` for details
+ AssociatedType(AssocTypeId<I>, Substitution<I>),
+
+ /// a scalar type like `bool` or `u32`
+ Scalar(Scalar),
+
+ /// a tuple of the given arity
+ Tuple(usize, Substitution<I>),
+
+ /// an array type like `[T; N]`
+ Array(Ty<I>, Const<I>),
+
+ /// a slice type like `[T]`
+ Slice(Ty<I>),
+
+ /// a raw pointer type like `*const T` or `*mut T`
+ Raw(Mutability, Ty<I>),
+
+ /// a reference type like `&T` or `&mut T`
+ Ref(Mutability, Lifetime<I>, Ty<I>),
+
+ /// a placeholder for opaque types like `impl Trait`
+ OpaqueType(OpaqueTyId<I>, Substitution<I>),
+
+ /// a function definition
+ FnDef(FnDefId<I>, Substitution<I>),
+
+ /// the string primitive type
+ Str,
+
+ /// the never type `!`
+ Never,
+
+ /// A closure.
+ Closure(ClosureId<I>, Substitution<I>),
+
+ /// A generator.
+ Generator(GeneratorId<I>, Substitution<I>),
+
+ /// A generator witness.
+ GeneratorWitness(GeneratorId<I>, Substitution<I>),
+
+ /// foreign types
+ Foreign(ForeignDefId<I>),
+
+ /// This can be used to represent an error, e.g. during name resolution of a type.
+ /// Chalk itself will not produce this, just pass it through when given.
+ Error,
+
+ /// instantiated from a universally quantified type, e.g., from
+ /// `forall<T> { .. }`. Stands in as a representative of "some
+ /// unknown type".
+ Placeholder(PlaceholderIndex),
+
+ /// A "dyn" type is a trait object type created via the "dyn Trait" syntax.
+ /// In the chalk parser, the traits that the object represents is parsed as
+ /// a QuantifiedInlineBound, and is then changed to a list of where clauses
+ /// during lowering.
+ ///
+ /// See the `Opaque` variant for a discussion about the use of
+ /// binders here.
+ Dyn(DynTy<I>),
+
+ /// An "alias" type represents some form of type alias, such as:
+ /// - An associated type projection like `<T as Iterator>::Item`
+ /// - `impl Trait` types
+ /// - Named type aliases like `type Foo<X> = Vec<X>`
+ Alias(AliasTy<I>),
+
+ /// A function type such as `for<'a> fn(&'a u32)`.
+ /// Note that "higher-ranked" types (starting with `for<>`) are either
+ /// function types or dyn types, and do not appear otherwise in Rust
+ /// surface syntax.
+ Function(FnPointer<I>),
+
+ /// References the binding at the given depth. The index is a [de
+ /// Bruijn index], so it counts back through the in-scope binders.
+ BoundVar(BoundVar),
+
+ /// Inference variable defined in the current inference context.
+ InferenceVar(InferenceVar, TyVariableKind),
+}
+
+impl<I: Interner> Copy for TyKind<I>
+where
+ I::InternedLifetime: Copy,
+ I::InternedSubstitution: Copy,
+ I::InternedVariableKinds: Copy,
+ I::InternedQuantifiedWhereClauses: Copy,
+ I::InternedType: Copy,
+ I::InternedConst: Copy,
+{
+}
+
+impl<I: Interner> TyKind<I> {
+ /// Casts the type data to a type.
+ pub fn intern(self, interner: I) -> Ty<I> {
+ Ty::new(interner, self)
+ }
+
+ /// Compute type flags for a TyKind
+ pub fn compute_flags(&self, interner: I) -> TypeFlags {
+ match self {
+ TyKind::Adt(_, substitution)
+ | TyKind::AssociatedType(_, substitution)
+ | TyKind::Tuple(_, substitution)
+ | TyKind::Closure(_, substitution)
+ | TyKind::Generator(_, substitution)
+ | TyKind::GeneratorWitness(_, substitution)
+ | TyKind::FnDef(_, substitution)
+ | TyKind::OpaqueType(_, substitution) => substitution.compute_flags(interner),
+ TyKind::Scalar(_) | TyKind::Str | TyKind::Never | TyKind::Foreign(_) => {
+ TypeFlags::empty()
+ }
+ TyKind::Error => TypeFlags::HAS_ERROR,
+ TyKind::Slice(ty) | TyKind::Raw(_, ty) => ty.data(interner).flags,
+ TyKind::Ref(_, lifetime, ty) => {
+ lifetime.compute_flags(interner) | ty.data(interner).flags
+ }
+ TyKind::Array(ty, const_ty) => {
+ let flags = ty.data(interner).flags;
+ let const_data = const_ty.data(interner);
+ flags
+ | const_data.ty.data(interner).flags
+ | match const_data.value {
+ ConstValue::BoundVar(_) | ConstValue::Concrete(_) => TypeFlags::empty(),
+ ConstValue::InferenceVar(_) => {
+ TypeFlags::HAS_CT_INFER | TypeFlags::STILL_FURTHER_SPECIALIZABLE
+ }
+ ConstValue::Placeholder(_) => {
+ TypeFlags::HAS_CT_PLACEHOLDER | TypeFlags::STILL_FURTHER_SPECIALIZABLE
+ }
+ }
+ }
+ TyKind::Placeholder(_) => TypeFlags::HAS_TY_PLACEHOLDER,
+ TyKind::Dyn(dyn_ty) => {
+ let lifetime_flags = dyn_ty.lifetime.compute_flags(interner);
+ let mut dyn_flags = TypeFlags::empty();
+ for var_kind in dyn_ty.bounds.skip_binders().iter(interner) {
+ match &(var_kind.skip_binders()) {
+ WhereClause::Implemented(trait_ref) => {
+ dyn_flags |= trait_ref.substitution.compute_flags(interner)
+ }
+ WhereClause::AliasEq(alias_eq) => {
+ dyn_flags |= alias_eq.alias.compute_flags(interner);
+ dyn_flags |= alias_eq.ty.data(interner).flags;
+ }
+ WhereClause::LifetimeOutlives(lifetime_outlives) => {
+ dyn_flags |= lifetime_outlives.a.compute_flags(interner)
+ | lifetime_outlives.b.compute_flags(interner);
+ }
+ WhereClause::TypeOutlives(type_outlives) => {
+ dyn_flags |= type_outlives.ty.data(interner).flags;
+ dyn_flags |= type_outlives.lifetime.compute_flags(interner);
+ }
+ }
+ }
+ lifetime_flags | dyn_flags
+ }
+ TyKind::Alias(alias_ty) => alias_ty.compute_flags(interner),
+ TyKind::BoundVar(_) => TypeFlags::empty(),
+ TyKind::InferenceVar(_, _) => TypeFlags::HAS_TY_INFER,
+ TyKind::Function(fn_pointer) => fn_pointer.substitution.0.compute_flags(interner),
+ }
+ }
+}
+
+/// Identifies a particular bound variable within a binder.
+/// Variables are identified by the combination of a [`DebruijnIndex`],
+/// which identifies the *binder*, and an index within that binder.
+///
+/// Consider this case:
+///
+/// ```ignore
+/// forall<'a, 'b> { forall<'c, 'd> { ... } }
+/// ```
+///
+/// Within the `...` term:
+///
+/// * the variable `'a` have a debruijn index of 1 and index 0
+/// * the variable `'b` have a debruijn index of 1 and index 1
+/// * the variable `'c` have a debruijn index of 0 and index 0
+/// * the variable `'d` have a debruijn index of 0 and index 1
+///
+/// The variables `'a` and `'b` both have debruijn index of 1 because,
+/// counting out, they are the 2nd binder enclosing `...`. The indices
+/// identify the location *within* that binder.
+///
+/// The variables `'c` and `'d` both have debruijn index of 0 because
+/// they appear in the *innermost* binder enclosing the `...`. The
+/// indices identify the location *within* that binder.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct BoundVar {
+ /// Debruijn index, which identifies the binder.
+ pub debruijn: DebruijnIndex,
+ /// Index within the binder.
+ pub index: usize,
+}
+
+impl BoundVar {
+ /// Creates a new bound variable.
+ pub fn new(debruijn: DebruijnIndex, index: usize) -> Self {
+ Self { debruijn, index }
+ }
+
+ /// Casts the bound variable to a type.
+ pub fn to_ty<I: Interner>(self, interner: I) -> Ty<I> {
+ TyKind::<I>::BoundVar(self).intern(interner)
+ }
+
+ /// Wrap the bound variable in a lifetime.
+ pub fn to_lifetime<I: Interner>(self, interner: I) -> Lifetime<I> {
+ LifetimeData::<I>::BoundVar(self).intern(interner)
+ }
+
+ /// Wraps the bound variable in a constant.
+ pub fn to_const<I: Interner>(self, interner: I, ty: Ty<I>) -> Const<I> {
+ ConstData {
+ ty,
+ value: ConstValue::<I>::BoundVar(self),
+ }
+ .intern(interner)
+ }
+
+ /// True if this variable is bound within the `amount` innermost binders.
+ pub fn bound_within(self, outer_binder: DebruijnIndex) -> bool {
+ self.debruijn.within(outer_binder)
+ }
+
+ /// Adjusts the debruijn index (see [`DebruijnIndex::shifted_in`]).
+ #[must_use]
+ pub fn shifted_in(self) -> Self {
+ BoundVar::new(self.debruijn.shifted_in(), self.index)
+ }
+
+ /// Adjusts the debruijn index (see [`DebruijnIndex::shifted_in`]).
+ #[must_use]
+ pub fn shifted_in_from(self, outer_binder: DebruijnIndex) -> Self {
+ BoundVar::new(self.debruijn.shifted_in_from(outer_binder), self.index)
+ }
+
+ /// Adjusts the debruijn index (see [`DebruijnIndex::shifted_in`]).
+ #[must_use]
+ pub fn shifted_out(self) -> Option<Self> {
+ self.debruijn
+ .shifted_out()
+ .map(|db| BoundVar::new(db, self.index))
+ }
+
+ /// Adjusts the debruijn index (see [`DebruijnIndex::shifted_in`]).
+ #[must_use]
+ pub fn shifted_out_to(self, outer_binder: DebruijnIndex) -> Option<Self> {
+ self.debruijn
+ .shifted_out_to(outer_binder)
+ .map(|db| BoundVar::new(db, self.index))
+ }
+
+ /// Return the index of the bound variable, but only if it is bound
+ /// at the innermost binder. Otherwise, returns `None`.
+ pub fn index_if_innermost(self) -> Option<usize> {
+ self.index_if_bound_at(DebruijnIndex::INNERMOST)
+ }
+
+ /// Return the index of the bound variable, but only if it is bound
+ /// at the innermost binder. Otherwise, returns `None`.
+ pub fn index_if_bound_at(self, debruijn: DebruijnIndex) -> Option<usize> {
+ if self.debruijn == debruijn {
+ Some(self.index)
+ } else {
+ None
+ }
+ }
+}
+
+/// References the binder at the given depth. The index is a [de
+/// Bruijn index], so it counts back through the in-scope binders,
+/// with 0 being the innermost binder. This is used in impls and
+/// the like. For example, if we had a rule like `for<T> { (T:
+/// Clone) :- (T: Copy) }`, then `T` would be represented as a
+/// `BoundVar(0)` (as the `for` is the innermost binder).
+///
+/// [de Bruijn index]: https://en.wikipedia.org/wiki/De_Bruijn_index
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct DebruijnIndex {
+ depth: u32,
+}
+
+impl DebruijnIndex {
+ /// Innermost index.
+ pub const INNERMOST: DebruijnIndex = DebruijnIndex { depth: 0 };
+ /// One level higher than the innermost index.
+ pub const ONE: DebruijnIndex = DebruijnIndex { depth: 1 };
+
+ /// Creates a new de Bruijn index with a given depth.
+ pub fn new(depth: u32) -> Self {
+ DebruijnIndex { depth }
+ }
+
+ /// Depth of the De Bruijn index, counting from 0 starting with
+ /// the innermost binder.
+ pub fn depth(self) -> u32 {
+ self.depth
+ }
+
+ /// True if the binder identified by this index is within the
+ /// binder identified by the index `outer_binder`.
+ ///
+ /// # Example
+ ///
+ /// Imagine you have the following binders in scope
+ ///
+ /// ```ignore
+ /// forall<a> forall<b> forall<c>
+ /// ```
+ ///
+ /// then the Debruijn index for `c` would be `0`, the index for
+ /// `b` would be 1, and so on. Now consider the following calls:
+ ///
+ /// * `c.within(a) = true`
+ /// * `b.within(a) = true`
+ /// * `a.within(a) = false`
+ /// * `a.within(c) = false`
+ pub fn within(self, outer_binder: DebruijnIndex) -> bool {
+ self < outer_binder
+ }
+
+ /// Returns the resulting index when this value is moved into
+ /// through one binder.
+ #[must_use]
+ pub fn shifted_in(self) -> DebruijnIndex {
+ self.shifted_in_from(DebruijnIndex::ONE)
+ }
+
+ /// Update this index in place by shifting it "in" through
+ /// `amount` number of binders.
+ pub fn shift_in(&mut self) {
+ *self = self.shifted_in();
+ }
+
+ /// Adds `outer_binder` levels to the `self` index. Intuitively, this
+ /// shifts the `self` index, which was valid at the outer binder,
+ /// so that it is valid at the innermost binder.
+ ///
+ /// Example: Assume that the following binders are in scope:
+ ///
+ /// ```ignore
+ /// for<A> for<B> for<C> for<D>
+ /// ^ outer binder
+ /// ```
+ ///
+ /// Assume further that the `outer_binder` argument is 2,
+ /// which means that it is referring to the `for<B>` binder
+ /// (since `D` would be the innermost binder).
+ ///
+ /// This means that `self` is relative to the binder `B` -- so
+ /// if `self` is 0 (`INNERMOST`), then it refers to `B`,
+ /// and if `self` is 1, then it refers to `A`.
+ ///
+ /// We will return as follows:
+ ///
+ /// * `0.shifted_in_from(2) = 2` -- i.e., `B`, when shifted in to the binding level `D`, has index 2
+ /// * `1.shifted_in_from(2) = 3` -- i.e., `A`, when shifted in to the binding level `D`, has index 3
+ /// * `2.shifted_in_from(1) = 3` -- here, we changed the `outer_binder` to refer to `C`.
+ /// Therefore `2` (relative to `C`) refers to `A`, so the result is still 3 (since `A`, relative to the
+ /// innermost binder, has index 3).
+ #[must_use]
+ pub fn shifted_in_from(self, outer_binder: DebruijnIndex) -> DebruijnIndex {
+ DebruijnIndex::new(self.depth() + outer_binder.depth())
+ }
+
+ /// Returns the resulting index when this value is moved out from
+ /// `amount` number of new binders.
+ #[must_use]
+ pub fn shifted_out(self) -> Option<DebruijnIndex> {
+ self.shifted_out_to(DebruijnIndex::ONE)
+ }
+
+ /// Update in place by shifting out from `amount` binders.
+ pub fn shift_out(&mut self) {
+ *self = self.shifted_out().unwrap();
+ }
+
+ /// Subtracts `outer_binder` levels from the `self` index. Intuitively, this
+ /// shifts the `self` index, which was valid at the innermost
+ /// binder, to one that is valid at the binder `outer_binder`.
+ ///
+ /// This will return `None` if the `self` index is internal to the
+ /// outer binder (i.e., if `self < outer_binder`).
+ ///
+ /// Example: Assume that the following binders are in scope:
+ ///
+ /// ```ignore
+ /// for<A> for<B> for<C> for<D>
+ /// ^ outer binder
+ /// ```
+ ///
+ /// Assume further that the `outer_binder` argument is 2,
+ /// which means that it is referring to the `for<B>` binder
+ /// (since `D` would be the innermost binder).
+ ///
+ /// This means that the result is relative to the binder `B` -- so
+ /// if `self` is 0 (`INNERMOST`), then it refers to `B`,
+ /// and if `self` is 1, then it refers to `A`.
+ ///
+ /// We will return as follows:
+ ///
+ /// * `1.shifted_out_to(2) = None` -- i.e., the binder for `C` can't be named from the binding level `B`
+ /// * `3.shifted_out_to(2) = Some(1)` -- i.e., `A`, when shifted out to the binding level `B`, has index 1
+ pub fn shifted_out_to(self, outer_binder: DebruijnIndex) -> Option<DebruijnIndex> {
+ if self.within(outer_binder) {
+ None
+ } else {
+ Some(DebruijnIndex::new(self.depth() - outer_binder.depth()))
+ }
+ }
+}
+
+/// A "DynTy" represents a trait object (`dyn Trait`). Trait objects
+/// are conceptually very related to an "existential type" of the form
+/// `exists<T> { T: Trait }` (another example of such type is `impl Trait`).
+/// `DynTy` represents the bounds on that type.
+///
+/// The "bounds" here represents the unknown self type. So, a type like
+/// `dyn for<'a> Fn(&'a u32)` would be represented with two-levels of
+/// binder, as "depicted" here:
+///
+/// ```notrust
+/// exists<type> {
+/// vec![
+/// // A QuantifiedWhereClause:
+/// forall<region> { ^1.0: Fn(&^0.0 u32) }
+/// ]
+/// }
+/// ```
+///
+/// The outer `exists<type>` binder indicates that there exists
+/// some type that meets the criteria within, but that type is not
+/// known. It is referenced within the type using `^1.0`, indicating
+/// a bound type with debruijn index 1 (i.e., skipping through one
+/// level of binder).
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct DynTy<I: Interner> {
+ /// The unknown self type.
+ pub bounds: Binders<QuantifiedWhereClauses<I>>,
+ /// Lifetime of the `DynTy`.
+ pub lifetime: Lifetime<I>,
+}
+
+impl<I: Interner> Copy for DynTy<I>
+where
+ I::InternedLifetime: Copy,
+ I::InternedQuantifiedWhereClauses: Copy,
+ I::InternedVariableKinds: Copy,
+{
+}
+
+/// A type, lifetime or constant whose value is being inferred.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct InferenceVar {
+ index: u32,
+}
+
+impl From<u32> for InferenceVar {
+ fn from(index: u32) -> InferenceVar {
+ InferenceVar { index }
+ }
+}
+
+impl InferenceVar {
+ /// Gets the underlying index value.
+ pub fn index(self) -> u32 {
+ self.index
+ }
+
+ /// Wraps the inference variable in a type.
+ pub fn to_ty<I: Interner>(self, interner: I, kind: TyVariableKind) -> Ty<I> {
+ TyKind::<I>::InferenceVar(self, kind).intern(interner)
+ }
+
+ /// Wraps the inference variable in a lifetime.
+ pub fn to_lifetime<I: Interner>(self, interner: I) -> Lifetime<I> {
+ LifetimeData::<I>::InferenceVar(self).intern(interner)
+ }
+
+ /// Wraps the inference variable in a constant.
+ pub fn to_const<I: Interner>(self, interner: I, ty: Ty<I>) -> Const<I> {
+ ConstData {
+ ty,
+ value: ConstValue::<I>::InferenceVar(self),
+ }
+ .intern(interner)
+ }
+}
+
+/// A function signature.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, HasInterner, Debug)]
+#[allow(missing_docs)]
+pub struct FnSig<I: Interner> {
+ pub abi: I::FnAbi,
+ pub safety: Safety,
+ pub variadic: bool,
+}
+/// A wrapper for the substs on a Fn.
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner, TypeFoldable, TypeVisitable)]
+pub struct FnSubst<I: Interner>(pub Substitution<I>);
+
+impl<I: Interner> Copy for FnSubst<I> where I::InternedSubstitution: Copy {}
+
+/// for<'a...'z> X -- all binders are instantiated at once,
+/// and we use deBruijn indices within `self.ty`
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner)]
+#[allow(missing_docs)]
+pub struct FnPointer<I: Interner> {
+ pub num_binders: usize,
+ pub sig: FnSig<I>,
+ pub substitution: FnSubst<I>,
+}
+
+impl<I: Interner> Copy for FnPointer<I> where I::InternedSubstitution: Copy {}
+
+impl<I: Interner> FnPointer<I> {
+ /// Represent the current `Fn` as if it was wrapped in `Binders`
+ pub fn into_binders(self, interner: I) -> Binders<FnSubst<I>> {
+ Binders::new(
+ VariableKinds::from_iter(
+ interner,
+ (0..self.num_binders).map(|_| VariableKind::Lifetime),
+ ),
+ self.substitution,
+ )
+ }
+
+ /// Represent the current `Fn` as if it was wrapped in `Binders`
+ pub fn as_binders(&self, interner: I) -> Binders<&FnSubst<I>> {
+ Binders::new(
+ VariableKinds::from_iter(
+ interner,
+ (0..self.num_binders).map(|_| VariableKind::Lifetime),
+ ),
+ &self.substitution,
+ )
+ }
+}
+
+/// Constants.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct Const<I: Interner> {
+ interned: I::InternedConst,
+}
+
+impl<I: Interner> Const<I> {
+ /// Create a `Const` using something that can be cast to const data.
+ pub fn new(interner: I, data: impl CastTo<ConstData<I>>) -> Self {
+ Const {
+ interned: I::intern_const(interner, data.cast(interner)),
+ }
+ }
+
+ /// Gets the interned constant.
+ pub fn interned(&self) -> &I::InternedConst {
+ &self.interned
+ }
+
+ /// Gets the constant data from the interner.
+ pub fn data(&self, interner: I) -> &ConstData<I> {
+ I::const_data(interner, &self.interned)
+ }
+
+ /// If this is a `ConstData::BoundVar(d)`, returns `Some(d)` else `None`.
+ pub fn bound_var(&self, interner: I) -> Option<BoundVar> {
+ if let ConstValue::BoundVar(bv) = &self.data(interner).value {
+ Some(*bv)
+ } else {
+ None
+ }
+ }
+
+ /// If this is a `ConstData::InferenceVar(d)`, returns `Some(d)` else `None`.
+ pub fn inference_var(&self, interner: I) -> Option<InferenceVar> {
+ if let ConstValue::InferenceVar(iv) = &self.data(interner).value {
+ Some(*iv)
+ } else {
+ None
+ }
+ }
+
+ /// True if this const is a "bound" const, and hence
+ /// needs to be shifted across binders. Meant for debug assertions.
+ pub fn needs_shift(&self, interner: I) -> bool {
+ match &self.data(interner).value {
+ ConstValue::BoundVar(_) => true,
+ ConstValue::InferenceVar(_) => false,
+ ConstValue::Placeholder(_) => false,
+ ConstValue::Concrete(_) => false,
+ }
+ }
+}
+
+/// Constant data, containing the constant's type and value.
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner)]
+pub struct ConstData<I: Interner> {
+ /// Type that holds the constant.
+ pub ty: Ty<I>,
+ /// The value of the constant.
+ pub value: ConstValue<I>,
+}
+
+/// A constant value, not necessarily concrete.
+#[derive(Clone, PartialEq, Eq, Hash, HasInterner)]
+pub enum ConstValue<I: Interner> {
+ /// Bound var (e.g. a parameter).
+ BoundVar(BoundVar),
+ /// Constant whose value is being inferred.
+ InferenceVar(InferenceVar),
+ /// Lifetime on some yet-unknown placeholder.
+ Placeholder(PlaceholderIndex),
+ /// Concrete constant value.
+ Concrete(ConcreteConst<I>),
+}
+
+impl<I: Interner> Copy for ConstValue<I> where I::InternedConcreteConst: Copy {}
+
+impl<I: Interner> ConstData<I> {
+ /// Wraps the constant data in a `Const`.
+ pub fn intern(self, interner: I) -> Const<I> {
+ Const::new(interner, self)
+ }
+}
+
+/// Concrete constant, whose value is known (as opposed to
+/// inferred constants and placeholders).
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct ConcreteConst<I: Interner> {
+ /// The interned constant.
+ pub interned: I::InternedConcreteConst,
+}
+
+impl<I: Interner> ConcreteConst<I> {
+ /// Checks whether two concrete constants are equal.
+ pub fn const_eq(&self, ty: &Ty<I>, other: &ConcreteConst<I>, interner: I) -> bool {
+ interner.const_eq(&ty.interned, &self.interned, &other.interned)
+ }
+}
+
+/// A Rust lifetime.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct Lifetime<I: Interner> {
+ interned: I::InternedLifetime,
+}
+
+impl<I: Interner> Lifetime<I> {
+ /// Create a lifetime from lifetime data
+ /// (or something that can be cast to lifetime data).
+ pub fn new(interner: I, data: impl CastTo<LifetimeData<I>>) -> Self {
+ Lifetime {
+ interned: I::intern_lifetime(interner, data.cast(interner)),
+ }
+ }
+
+ /// Gets the interned value.
+ pub fn interned(&self) -> &I::InternedLifetime {
+ &self.interned
+ }
+
+ /// Gets the lifetime data.
+ pub fn data(&self, interner: I) -> &LifetimeData<I> {
+ I::lifetime_data(interner, &self.interned)
+ }
+
+ /// If this is a `Lifetime::BoundVar(d)`, returns `Some(d)` else `None`.
+ pub fn bound_var(&self, interner: I) -> Option<BoundVar> {
+ if let LifetimeData::BoundVar(bv) = self.data(interner) {
+ Some(*bv)
+ } else {
+ None
+ }
+ }
+
+ /// If this is a `Lifetime::InferenceVar(d)`, returns `Some(d)` else `None`.
+ pub fn inference_var(&self, interner: I) -> Option<InferenceVar> {
+ if let LifetimeData::InferenceVar(depth) = self.data(interner) {
+ Some(*depth)
+ } else {
+ None
+ }
+ }
+
+ /// True if this lifetime is a "bound" lifetime, and hence
+ /// needs to be shifted across binders. Meant for debug assertions.
+ pub fn needs_shift(&self, interner: I) -> bool {
+ match self.data(interner) {
+ LifetimeData::BoundVar(_) => true,
+ LifetimeData::InferenceVar(_) => false,
+ LifetimeData::Placeholder(_) => false,
+ LifetimeData::Static => false,
+ LifetimeData::Erased => false,
+ LifetimeData::Phantom(..) => unreachable!(),
+ }
+ }
+
+ ///compute type flags for Lifetime
+ fn compute_flags(&self, interner: I) -> TypeFlags {
+ match self.data(interner) {
+ LifetimeData::InferenceVar(_) => {
+ TypeFlags::HAS_RE_INFER
+ | TypeFlags::HAS_FREE_LOCAL_REGIONS
+ | TypeFlags::HAS_FREE_REGIONS
+ }
+ LifetimeData::Placeholder(_) => {
+ TypeFlags::HAS_RE_PLACEHOLDER
+ | TypeFlags::HAS_FREE_LOCAL_REGIONS
+ | TypeFlags::HAS_FREE_REGIONS
+ }
+ LifetimeData::Static => TypeFlags::HAS_FREE_REGIONS,
+ LifetimeData::Phantom(_, _) => TypeFlags::empty(),
+ LifetimeData::BoundVar(_) => TypeFlags::HAS_RE_LATE_BOUND,
+ LifetimeData::Erased => TypeFlags::HAS_RE_ERASED,
+ }
+ }
+}
+
+/// Lifetime data, including what kind of lifetime it is and what it points to.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub enum LifetimeData<I: Interner> {
+ /// See TyKind::BoundVar.
+ BoundVar(BoundVar),
+ /// Lifetime whose value is being inferred.
+ InferenceVar(InferenceVar),
+ /// Lifetime on some yet-unknown placeholder.
+ Placeholder(PlaceholderIndex),
+ /// Static lifetime
+ Static,
+ /// An erased lifetime, used by rustc to improve caching when we doesn't
+ /// care about lifetimes
+ Erased,
+ /// Lifetime on phantom data.
+ Phantom(Void, PhantomData<I>),
+}
+
+impl<I: Interner> LifetimeData<I> {
+ /// Wrap the lifetime data in a lifetime.
+ pub fn intern(self, interner: I) -> Lifetime<I> {
+ Lifetime::new(interner, self)
+ }
+}
+
+/// Index of an universally quantified parameter in the environment.
+/// Two indexes are required, the one of the universe itself
+/// and the relative index inside the universe.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct PlaceholderIndex {
+ /// Index *of* the universe.
+ pub ui: UniverseIndex,
+ /// Index *in* the universe.
+ pub idx: usize,
+}
+
+impl PlaceholderIndex {
+ /// Wrap the placeholder instance in a lifetime.
+ pub fn to_lifetime<I: Interner>(self, interner: I) -> Lifetime<I> {
+ LifetimeData::<I>::Placeholder(self).intern(interner)
+ }
+
+ /// Create an interned type.
+ pub fn to_ty<I: Interner>(self, interner: I) -> Ty<I> {
+ TyKind::Placeholder(self).intern(interner)
+ }
+
+ /// Wrap the placeholder index in a constant.
+ pub fn to_const<I: Interner>(self, interner: I, ty: Ty<I>) -> Const<I> {
+ ConstData {
+ ty,
+ value: ConstValue::Placeholder(self),
+ }
+ .intern(interner)
+ }
+}
+/// Represents some extra knowledge we may have about the type variable.
+/// ```ignore
+/// let x: &[u32];
+/// let i = 1;
+/// x[i]
+/// ```
+/// In this example, `i` is known to be some type of integer. We can infer that
+/// it is `usize` because that is the only integer type that slices have an
+/// `Index` impl for. `i` would have a `TyVariableKind` of `Integer` to guide the
+/// inference process.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[allow(missing_docs)]
+pub enum TyVariableKind {
+ General,
+ Integer,
+ Float,
+}
+
+/// The "kind" of variable. Type, lifetime or constant.
+#[derive(Clone, PartialEq, Eq, Hash)]
+#[allow(missing_docs)]
+pub enum VariableKind<I: Interner> {
+ Ty(TyVariableKind),
+ Lifetime,
+ Const(Ty<I>),
+}
+
+impl<I: Interner> interner::HasInterner for VariableKind<I> {
+ type Interner = I;
+}
+
+impl<I: Interner> Copy for VariableKind<I> where I::InternedType: Copy {}
+
+impl<I: Interner> VariableKind<I> {
+ fn to_bound_variable(&self, interner: I, bound_var: BoundVar) -> GenericArg<I> {
+ match self {
+ VariableKind::Ty(_) => {
+ GenericArgData::Ty(TyKind::BoundVar(bound_var).intern(interner)).intern(interner)
+ }
+ VariableKind::Lifetime => {
+ GenericArgData::Lifetime(LifetimeData::BoundVar(bound_var).intern(interner))
+ .intern(interner)
+ }
+ VariableKind::Const(ty) => GenericArgData::Const(
+ ConstData {
+ ty: ty.clone(),
+ value: ConstValue::BoundVar(bound_var),
+ }
+ .intern(interner),
+ )
+ .intern(interner),
+ }
+ }
+}
+
+/// A generic argument, see `GenericArgData` for more information.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct GenericArg<I: Interner> {
+ interned: I::InternedGenericArg,
+}
+
+impl<I: Interner> GenericArg<I> {
+ /// Constructs a generic argument using `GenericArgData`.
+ pub fn new(interner: I, data: GenericArgData<I>) -> Self {
+ let interned = I::intern_generic_arg(interner, data);
+ GenericArg { interned }
+ }
+
+ /// Gets the interned value.
+ pub fn interned(&self) -> &I::InternedGenericArg {
+ &self.interned
+ }
+
+ /// Gets the underlying data.
+ pub fn data(&self, interner: I) -> &GenericArgData<I> {
+ I::generic_arg_data(interner, &self.interned)
+ }
+
+ /// Asserts that this is a type argument.
+ pub fn assert_ty_ref(&self, interner: I) -> &Ty<I> {
+ self.ty(interner).unwrap()
+ }
+
+ /// Asserts that this is a lifetime argument.
+ pub fn assert_lifetime_ref(&self, interner: I) -> &Lifetime<I> {
+ self.lifetime(interner).unwrap()
+ }
+
+ /// Asserts that this is a constant argument.
+ pub fn assert_const_ref(&self, interner: I) -> &Const<I> {
+ self.constant(interner).unwrap()
+ }
+
+ /// Checks whether the generic argument is a type.
+ pub fn is_ty(&self, interner: I) -> bool {
+ match self.data(interner) {
+ GenericArgData::Ty(_) => true,
+ GenericArgData::Lifetime(_) => false,
+ GenericArgData::Const(_) => false,
+ }
+ }
+
+ /// Returns the type if it is one, `None` otherwise.
+ pub fn ty(&self, interner: I) -> Option<&Ty<I>> {
+ match self.data(interner) {
+ GenericArgData::Ty(t) => Some(t),
+ _ => None,
+ }
+ }
+
+ /// Returns the lifetime if it is one, `None` otherwise.
+ pub fn lifetime(&self, interner: I) -> Option<&Lifetime<I>> {
+ match self.data(interner) {
+ GenericArgData::Lifetime(t) => Some(t),
+ _ => None,
+ }
+ }
+
+ /// Returns the constant if it is one, `None` otherwise.
+ pub fn constant(&self, interner: I) -> Option<&Const<I>> {
+ match self.data(interner) {
+ GenericArgData::Const(c) => Some(c),
+ _ => None,
+ }
+ }
+
+ /// Compute type flags for GenericArg<I>
+ fn compute_flags(&self, interner: I) -> TypeFlags {
+ match self.data(interner) {
+ GenericArgData::Ty(ty) => ty.data(interner).flags,
+ GenericArgData::Lifetime(lifetime) => lifetime.compute_flags(interner),
+ GenericArgData::Const(constant) => {
+ let data = constant.data(interner);
+ let flags = data.ty.data(interner).flags;
+ match data.value {
+ ConstValue::BoundVar(_) => flags,
+ ConstValue::InferenceVar(_) => {
+ flags | TypeFlags::HAS_CT_INFER | TypeFlags::STILL_FURTHER_SPECIALIZABLE
+ }
+ ConstValue::Placeholder(_) => {
+ flags
+ | TypeFlags::HAS_CT_PLACEHOLDER
+ | TypeFlags::STILL_FURTHER_SPECIALIZABLE
+ }
+ ConstValue::Concrete(_) => flags,
+ }
+ }
+ }
+ }
+}
+
+/// Generic arguments data.
+#[derive(Clone, PartialEq, Eq, Hash, TypeVisitable, TypeFoldable, Zip)]
+pub enum GenericArgData<I: Interner> {
+ /// Type argument
+ Ty(Ty<I>),
+ /// Lifetime argument
+ Lifetime(Lifetime<I>),
+ /// Constant argument
+ Const(Const<I>),
+}
+
+impl<I: Interner> Copy for GenericArgData<I>
+where
+ I::InternedType: Copy,
+ I::InternedLifetime: Copy,
+ I::InternedConst: Copy,
+{
+}
+
+impl<I: Interner> GenericArgData<I> {
+ /// Create an interned type.
+ pub fn intern(self, interner: I) -> GenericArg<I> {
+ GenericArg::new(interner, self)
+ }
+}
+
+/// A value with an associated variable kind.
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct WithKind<I: Interner, T> {
+ /// The associated variable kind.
+ pub kind: VariableKind<I>,
+ /// The wrapped value.
+ value: T,
+}
+
+impl<I: Interner, T: Copy> Copy for WithKind<I, T> where I::InternedType: Copy {}
+
+impl<I: Interner, T> HasInterner for WithKind<I, T> {
+ type Interner = I;
+}
+
+impl<I: Interner, T> From<WithKind<I, T>> for (VariableKind<I>, T) {
+ fn from(with_kind: WithKind<I, T>) -> Self {
+ (with_kind.kind, with_kind.value)
+ }
+}
+
+impl<I: Interner, T> WithKind<I, T> {
+ /// Creates a `WithKind` from a variable kind and a value.
+ pub fn new(kind: VariableKind<I>, value: T) -> Self {
+ Self { kind, value }
+ }
+
+ /// Maps the value in `WithKind`.
+ pub fn map<U, OP>(self, op: OP) -> WithKind<I, U>
+ where
+ OP: FnOnce(T) -> U,
+ {
+ WithKind {
+ kind: self.kind,
+ value: op(self.value),
+ }
+ }
+
+ /// Maps a function taking `WithKind<I, &T>` over `&WithKind<I, T>`.
+ pub fn map_ref<U, OP>(&self, op: OP) -> WithKind<I, U>
+ where
+ OP: FnOnce(&T) -> U,
+ {
+ WithKind {
+ kind: self.kind.clone(),
+ value: op(&self.value),
+ }
+ }
+
+ /// Extract the value, ignoring the variable kind.
+ pub fn skip_kind(&self) -> &T {
+ &self.value
+ }
+}
+
+/// A variable kind with universe index.
+#[allow(type_alias_bounds)]
+pub type CanonicalVarKind<I: Interner> = WithKind<I, UniverseIndex>;
+
+/// An alias, which is a trait indirection such as a projection or opaque type.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub enum AliasTy<I: Interner> {
+ /// An associated type projection.
+ Projection(ProjectionTy<I>),
+ /// An opaque type.
+ Opaque(OpaqueTy<I>),
+}
+
+impl<I: Interner> Copy for AliasTy<I> where I::InternedSubstitution: Copy {}
+
+impl<I: Interner> AliasTy<I> {
+ /// Create an interned type for this alias.
+ pub fn intern(self, interner: I) -> Ty<I> {
+ Ty::new(interner, self)
+ }
+
+ /// Compute type flags for aliases
+ fn compute_flags(&self, interner: I) -> TypeFlags {
+ match self {
+ AliasTy::Projection(projection_ty) => {
+ TypeFlags::HAS_TY_PROJECTION | projection_ty.substitution.compute_flags(interner)
+ }
+ AliasTy::Opaque(opaque_ty) => {
+ TypeFlags::HAS_TY_OPAQUE | opaque_ty.substitution.compute_flags(interner)
+ }
+ }
+ }
+}
+
+/// A projection `<P0 as TraitName<P1..Pn>>::AssocItem<Pn+1..Pm>`.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct ProjectionTy<I: Interner> {
+ /// The id for the associated type member.
+ pub associated_ty_id: AssocTypeId<I>,
+ /// The substitution for the projection.
+ pub substitution: Substitution<I>,
+}
+
+impl<I: Interner> Copy for ProjectionTy<I> where I::InternedSubstitution: Copy {}
+
+/// An opaque type `opaque type T<..>: Trait = HiddenTy`.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct OpaqueTy<I: Interner> {
+ /// The id for the opaque type.
+ pub opaque_ty_id: OpaqueTyId<I>,
+ /// The substitution for the opaque type.
+ pub substitution: Substitution<I>,
+}
+
+impl<I: Interner> Copy for OpaqueTy<I> where I::InternedSubstitution: Copy {}
+
+/// A trait reference describes the relationship between a type and a trait.
+/// This can be used in two forms:
+/// - `P0: Trait<P1..Pn>` (e.g. `i32: Copy`), which mentions that the type
+/// implements the trait.
+/// - `<P0 as Trait<P1..Pn>>` (e.g. `i32 as Copy`), which casts the type to
+/// that specific trait.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct TraitRef<I: Interner> {
+ /// The trait id.
+ pub trait_id: TraitId<I>,
+ /// The substitution, containing both the `Self` type and the parameters.
+ pub substitution: Substitution<I>,
+}
+
+impl<I: Interner> Copy for TraitRef<I> where I::InternedSubstitution: Copy {}
+
+impl<I: Interner> TraitRef<I> {
+ /// Gets all type parameters in this trait ref, including `Self`.
+ pub fn type_parameters(&self, interner: I) -> impl Iterator<Item = Ty<I>> + '_ {
+ self.substitution
+ .iter(interner)
+ .filter_map(move |p| p.ty(interner))
+ .cloned()
+ }
+
+ /// Gets the type parameters of the `Self` type in this trait ref.
+ pub fn self_type_parameter(&self, interner: I) -> Ty<I> {
+ self.type_parameters(interner).next().unwrap()
+ }
+
+ /// Construct a `FromEnv` using this trait ref.
+ pub fn from_env(self) -> FromEnv<I> {
+ FromEnv::Trait(self)
+ }
+
+ /// Construct a `WellFormed` using this trait ref.
+ pub fn well_formed(self) -> WellFormed<I> {
+ WellFormed::Trait(self)
+ }
+}
+
+/// Lifetime outlives, which for `'a: 'b`` checks that the lifetime `'a`
+/// is a superset of the value of `'b`.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+#[allow(missing_docs)]
+pub struct LifetimeOutlives<I: Interner> {
+ pub a: Lifetime<I>,
+ pub b: Lifetime<I>,
+}
+
+impl<I: Interner> Copy for LifetimeOutlives<I> where I::InternedLifetime: Copy {}
+
+/// Type outlives, which for `T: 'a` checks that the type `T`
+/// lives at least as long as the lifetime `'a`
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub struct TypeOutlives<I: Interner> {
+ /// The type which must outlive the given lifetime.
+ pub ty: Ty<I>,
+ /// The lifetime which the type must outlive.
+ pub lifetime: Lifetime<I>,
+}
+
+impl<I: Interner> Copy for TypeOutlives<I>
+where
+ I::InternedLifetime: Copy,
+ I::InternedType: Copy,
+{
+}
+
+/// Where clauses that can be written by a Rust programmer.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeSuperVisitable, HasInterner, Zip)]
+pub enum WhereClause<I: Interner> {
+ /// Type implements a trait.
+ Implemented(TraitRef<I>),
+ /// Type is equal to an alias.
+ AliasEq(AliasEq<I>),
+ /// One lifetime outlives another.
+ LifetimeOutlives(LifetimeOutlives<I>),
+ /// Type outlives a lifetime.
+ TypeOutlives(TypeOutlives<I>),
+}
+
+impl<I: Interner> Copy for WhereClause<I>
+where
+ I::InternedSubstitution: Copy,
+ I::InternedLifetime: Copy,
+ I::InternedType: Copy,
+{
+}
+
+/// Checks whether a type or trait ref is well-formed.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub enum WellFormed<I: Interner> {
+ /// A predicate which is true when some trait ref is well-formed.
+ /// For example, given the following trait definitions:
+ ///
+ /// ```notrust
+ /// trait Clone { ... }
+ /// trait Copy where Self: Clone { ... }
+ /// ```
+ ///
+ /// then we have the following rule:
+ ///
+ /// ```notrust
+ /// WellFormed(?Self: Copy) :- ?Self: Copy, WellFormed(?Self: Clone)
+ /// ```
+ Trait(TraitRef<I>),
+
+ /// A predicate which is true when some type is well-formed.
+ /// For example, given the following type definition:
+ ///
+ /// ```notrust
+ /// struct Set<K> where K: Hash {
+ /// ...
+ /// }
+ /// ```
+ ///
+ /// then we have the following rule: `WellFormedTy(Set<K>) :- Implemented(K: Hash)`.
+ Ty(Ty<I>),
+}
+
+impl<I: Interner> Copy for WellFormed<I>
+where
+ I::InternedType: Copy,
+ I::InternedSubstitution: Copy,
+{
+}
+
+/// Checks whether a type or trait ref can be derived from the contents of the environment.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub enum FromEnv<I: Interner> {
+ /// A predicate which enables deriving everything which should be true if we *know* that
+ /// some trait ref is well-formed. For example given the above trait definitions, we can use
+ /// `FromEnv(T: Copy)` to derive that `T: Clone`, like in:
+ ///
+ /// ```notrust
+ /// forall<T> {
+ /// if (FromEnv(T: Copy)) {
+ /// T: Clone
+ /// }
+ /// }
+ /// ```
+ Trait(TraitRef<I>),
+
+ /// A predicate which enables deriving everything which should be true if we *know* that
+ /// some type is well-formed. For example given the above type definition, we can use
+ /// `FromEnv(Set<K>)` to derive that `K: Hash`, like in:
+ ///
+ /// ```notrust
+ /// forall<K> {
+ /// if (FromEnv(Set<K>)) {
+ /// K: Hash
+ /// }
+ /// }
+ /// ```
+ Ty(Ty<I>),
+}
+
+impl<I: Interner> Copy for FromEnv<I>
+where
+ I::InternedType: Copy,
+ I::InternedSubstitution: Copy,
+{
+}
+
+/// A "domain goal" is a goal that is directly about Rust, rather than a pure
+/// logical statement. As much as possible, the Chalk solver should avoid
+/// decomposing this enum, and instead treat its values opaquely.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeSuperVisitable, HasInterner, Zip)]
+pub enum DomainGoal<I: Interner> {
+ /// Simple goal that is true if the where clause is true.
+ Holds(WhereClause<I>),
+
+ /// True if the type or trait ref is well-formed.
+ WellFormed(WellFormed<I>),
+
+ /// True if the trait ref can be derived from in-scope where clauses.
+ FromEnv(FromEnv<I>),
+
+ /// True if the alias type can be normalized to some other type
+ Normalize(Normalize<I>),
+
+ /// True if a type is considered to have been "defined" by the current crate. This is true for
+ /// a `struct Foo { }` but false for a `#[upstream] struct Foo { }`. However, for fundamental types
+ /// like `Box<T>`, it is true if `T` is local.
+ IsLocal(Ty<I>),
+
+ /// True if a type is *not* considered to have been "defined" by the current crate. This is
+ /// false for a `struct Foo { }` but true for a `#[upstream] struct Foo { }`. However, for
+ /// fundamental types like `Box<T>`, it is true if `T` is upstream.
+ IsUpstream(Ty<I>),
+
+ /// True if a type and its input types are fully visible, known types. That is, there are no
+ /// unknown type parameters anywhere in this type.
+ ///
+ /// More formally, for each struct S<P0..Pn>:
+ /// forall<P0..Pn> {
+ /// IsFullyVisible(S<P0...Pn>) :-
+ /// IsFullyVisible(P0),
+ /// ...
+ /// IsFullyVisible(Pn)
+ /// }
+ ///
+ /// Note that any of these types can have lifetimes in their parameters too, but we only
+ /// consider type parameters.
+ IsFullyVisible(Ty<I>),
+
+ /// Used to dictate when trait impls are allowed in the current (local) crate based on the
+ /// orphan rules.
+ ///
+ /// `LocalImplAllowed(T: Trait)` is true if the type T is allowed to impl trait Trait in
+ /// the current crate. Under the current rules, this is unconditionally true for all types if
+ /// the Trait is considered to be "defined" in the current crate. If that is not the case, then
+ /// `LocalImplAllowed(T: Trait)` can still be true if `IsLocal(T)` is true.
+ LocalImplAllowed(TraitRef<I>),
+
+ /// Used to activate the "compatible modality" rules. Rules that introduce predicates that have
+ /// to do with "all compatible universes" should depend on this clause so that they only apply
+ /// if this is present.
+ Compatible,
+
+ /// Used to indicate that a given type is in a downstream crate. Downstream crates contain the
+ /// current crate at some level of their dependencies.
+ ///
+ /// Since chalk does not actually see downstream types, this is usually introduced with
+ /// implication on a fresh, universally quantified type.
+ ///
+ /// forall<T> { if (DownstreamType(T)) { /* ... */ } }
+ ///
+ /// This makes a new type `T` available and makes `DownstreamType(T)` provable for that type.
+ DownstreamType(Ty<I>),
+
+ /// Used to activate the "reveal mode", in which opaque (`impl Trait`) types can be equated
+ /// to their actual type.
+ Reveal,
+
+ /// Used to indicate that a trait is object safe.
+ ObjectSafe(TraitId<I>),
+}
+
+impl<I: Interner> Copy for DomainGoal<I>
+where
+ I::InternedSubstitution: Copy,
+ I::InternedLifetime: Copy,
+ I::InternedType: Copy,
+{
+}
+
+/// A where clause that can contain `forall<>` or `exists<>` quantifiers.
+pub type QuantifiedWhereClause<I> = Binders<WhereClause<I>>;
+
+impl<I: Interner> WhereClause<I> {
+ /// Turn a where clause into the WF version of it i.e.:
+ /// * `Implemented(T: Trait)` maps to `WellFormed(T: Trait)`
+ /// * `ProjectionEq(<T as Trait>::Item = Foo)` maps to `WellFormed(<T as Trait>::Item = Foo)`
+ /// * any other clause maps to itself
+ pub fn into_well_formed_goal(self, interner: I) -> DomainGoal<I> {
+ match self {
+ WhereClause::Implemented(trait_ref) => WellFormed::Trait(trait_ref).cast(interner),
+ wc => wc.cast(interner),
+ }
+ }
+
+ /// Same as `into_well_formed_goal` but with the `FromEnv` predicate instead of `WellFormed`.
+ pub fn into_from_env_goal(self, interner: I) -> DomainGoal<I> {
+ match self {
+ WhereClause::Implemented(trait_ref) => FromEnv::Trait(trait_ref).cast(interner),
+ wc => wc.cast(interner),
+ }
+ }
+
+ /// If where clause is a `TraitRef`, returns its trait id.
+ pub fn trait_id(&self) -> Option<TraitId<I>> {
+ match self {
+ WhereClause::Implemented(trait_ref) => Some(trait_ref.trait_id),
+ WhereClause::AliasEq(_) => None,
+ WhereClause::LifetimeOutlives(_) => None,
+ WhereClause::TypeOutlives(_) => None,
+ }
+ }
+}
+
+impl<I: Interner> QuantifiedWhereClause<I> {
+ /// As with `WhereClause::into_well_formed_goal`, but for a
+ /// quantified where clause. For example, `forall<T> {
+ /// Implemented(T: Trait)}` would map to `forall<T> {
+ /// WellFormed(T: Trait) }`.
+ pub fn into_well_formed_goal(self, interner: I) -> Binders<DomainGoal<I>> {
+ self.map(|wc| wc.into_well_formed_goal(interner))
+ }
+
+ /// As with `WhereClause::into_from_env_goal`, but mapped over any
+ /// binders. For example, `forall<T> {
+ /// Implemented(T: Trait)}` would map to `forall<T> {
+ /// FromEnv(T: Trait) }`.
+ pub fn into_from_env_goal(self, interner: I) -> Binders<DomainGoal<I>> {
+ self.map(|wc| wc.into_from_env_goal(interner))
+ }
+
+ /// If the underlying where clause is a `TraitRef`, returns its trait id.
+ pub fn trait_id(&self) -> Option<TraitId<I>> {
+ self.skip_binders().trait_id()
+ }
+}
+
+impl<I: Interner> DomainGoal<I> {
+ /// Convert `Implemented(...)` into `FromEnv(...)`, but leave other
+ /// goals unchanged.
+ pub fn into_from_env_goal(self, interner: I) -> DomainGoal<I> {
+ match self {
+ DomainGoal::Holds(wc) => wc.into_from_env_goal(interner),
+ goal => goal,
+ }
+ }
+
+ /// Lists generic arguments that are inputs to this domain goal.
+ pub fn inputs(&self, interner: I) -> Vec<GenericArg<I>> {
+ match self {
+ DomainGoal::Holds(WhereClause::AliasEq(alias_eq)) => {
+ vec![GenericArgData::Ty(alias_eq.alias.clone().intern(interner)).intern(interner)]
+ }
+ _ => Vec::new(),
+ }
+ }
+}
+
+/// Equality goal: tries to prove that two values are equal.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, Zip)]
+#[allow(missing_docs)]
+pub struct EqGoal<I: Interner> {
+ pub a: GenericArg<I>,
+ pub b: GenericArg<I>,
+}
+
+impl<I: Interner> Copy for EqGoal<I> where I::InternedGenericArg: Copy {}
+
+/// Subtype goal: tries to prove that `a` is a subtype of `b`
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, Zip)]
+#[allow(missing_docs)]
+pub struct SubtypeGoal<I: Interner> {
+ pub a: Ty<I>,
+ pub b: Ty<I>,
+}
+
+impl<I: Interner> Copy for SubtypeGoal<I> where I::InternedType: Copy {}
+
+/// Proves that the given type alias **normalizes** to the given
+/// type. A projection `T::Foo` normalizes to the type `U` if we can
+/// **match it to an impl** and that impl has a `type Foo = V` where
+/// `U = V`.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, Zip)]
+#[allow(missing_docs)]
+pub struct Normalize<I: Interner> {
+ pub alias: AliasTy<I>,
+ pub ty: Ty<I>,
+}
+
+impl<I: Interner> Copy for Normalize<I>
+where
+ I::InternedSubstitution: Copy,
+ I::InternedType: Copy,
+{
+}
+
+/// Proves **equality** between an alias and a type.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, Zip)]
+#[allow(missing_docs)]
+pub struct AliasEq<I: Interner> {
+ pub alias: AliasTy<I>,
+ pub ty: Ty<I>,
+}
+
+impl<I: Interner> Copy for AliasEq<I>
+where
+ I::InternedSubstitution: Copy,
+ I::InternedType: Copy,
+{
+}
+
+impl<I: Interner> HasInterner for AliasEq<I> {
+ type Interner = I;
+}
+
+/// Indicates that the `value` is universally quantified over `N`
+/// parameters of the given kinds, where `N == self.binders.len()`. A
+/// variable with depth `i < N` refers to the value at
+/// `self.binders[i]`. Variables with depth `>= N` are free.
+///
+/// (IOW, we use deBruijn indices, where binders are introduced in reverse order
+/// of `self.binders`.)
+#[derive(Clone, PartialEq, Eq, Hash)]
+pub struct Binders<T: HasInterner> {
+ /// The binders that quantify over the value.
+ pub binders: VariableKinds<T::Interner>,
+
+ /// The value being quantified over.
+ value: T,
+}
+
+impl<T: HasInterner + Copy> Copy for Binders<T> where
+ <T::Interner as Interner>::InternedVariableKinds: Copy
+{
+}
+
+impl<T: HasInterner> HasInterner for Binders<T> {
+ type Interner = T::Interner;
+}
+
+impl<T: Clone + HasInterner> Binders<&T> {
+ /// Converts a `Binders<&T>` to a `Binders<T>` by cloning `T`.
+ pub fn cloned(self) -> Binders<T> {
+ self.map(Clone::clone)
+ }
+}
+
+impl<T: HasInterner> Binders<T> {
+ /// Create new binders.
+ pub fn new(binders: VariableKinds<T::Interner>, value: T) -> Self {
+ Self { binders, value }
+ }
+
+ /// Wraps the given value in a binder without variables, i.e. `for<>
+ /// (value)`. Since our deBruijn indices count binders, not variables, this
+ /// is sometimes useful.
+ pub fn empty(interner: T::Interner, value: T) -> Self {
+ let binders = VariableKinds::empty(interner);
+ Self { binders, value }
+ }
+
+ /// Skips the binder and returns the "bound" value. This is a
+ /// risky thing to do because it's easy to get confused about
+ /// De Bruijn indices and the like. `skip_binder` is only valid
+ /// when you are either extracting data that has nothing to
+ /// do with bound vars, or you are being very careful about
+ /// your depth accounting.
+ ///
+ /// Some examples where `skip_binder` is reasonable:
+ ///
+ /// - extracting the `TraitId` from a TraitRef;
+ /// - checking if there are any fields in a StructDatum
+ pub fn skip_binders(&self) -> &T {
+ &self.value
+ }
+
+ /// Skips the binder and returns the "bound" value as well as the skipped free variables. This
+ /// is just as risky as [`skip_binders`][Self::skip_binders].
+ pub fn into_value_and_skipped_binders(self) -> (T, VariableKinds<T::Interner>) {
+ (self.value, self.binders)
+ }
+
+ /// Converts `&Binders<T>` to `Binders<&T>`. Produces new `Binders`
+ /// with cloned quantifiers containing a reference to the original
+ /// value, leaving the original in place.
+ pub fn as_ref(&self) -> Binders<&T> {
+ Binders {
+ binders: self.binders.clone(),
+ value: &self.value,
+ }
+ }
+
+ /// Maps the binders by applying a function.
+ pub fn map<U, OP>(self, op: OP) -> Binders<U>
+ where
+ OP: FnOnce(T) -> U,
+ U: HasInterner<Interner = T::Interner>,
+ {
+ let value = op(self.value);
+ Binders {
+ binders: self.binders,
+ value,
+ }
+ }
+
+ /// Transforms the inner value according to the given function; returns
+ /// `None` if the function returns `None`.
+ pub fn filter_map<U, OP>(self, op: OP) -> Option<Binders<U>>
+ where
+ OP: FnOnce(T) -> Option<U>,
+ U: HasInterner<Interner = T::Interner>,
+ {
+ let value = op(self.value)?;
+ Some(Binders {
+ binders: self.binders,
+ value,
+ })
+ }
+
+ /// Maps a function taking `Binders<&T>` over `&Binders<T>`.
+ pub fn map_ref<'a, U, OP>(&'a self, op: OP) -> Binders<U>
+ where
+ OP: FnOnce(&'a T) -> U,
+ U: HasInterner<Interner = T::Interner>,
+ {
+ self.as_ref().map(op)
+ }
+
+ /// Creates a `Substitution` containing bound vars such that applying this
+ /// substitution will not change the value, i.e. `^0.0, ^0.1, ^0.2` and so
+ /// on.
+ pub fn identity_substitution(&self, interner: T::Interner) -> Substitution<T::Interner> {
+ Substitution::from_iter(
+ interner,
+ self.binders
+ .iter(interner)
+ .enumerate()
+ .map(|p| p.to_generic_arg(interner)),
+ )
+ }
+
+ /// Creates a fresh binders that contains a single type
+ /// variable. The result of the closure will be embedded in this
+ /// binder. Note that you should be careful with what you return
+ /// from the closure to account for the binder that will be added.
+ ///
+ /// XXX FIXME -- this is potentially a pretty footgun-y function.
+ pub fn with_fresh_type_var(
+ interner: T::Interner,
+ op: impl FnOnce(Ty<T::Interner>) -> T,
+ ) -> Binders<T> {
+ // The new variable is at the front and everything afterwards is shifted up by 1
+ let new_var = TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0)).intern(interner);
+ let value = op(new_var);
+ let binders = VariableKinds::from1(interner, VariableKind::Ty(TyVariableKind::General));
+ Binders { binders, value }
+ }
+
+ /// Returns the number of binders.
+ pub fn len(&self, interner: T::Interner) -> usize {
+ self.binders.len(interner)
+ }
+}
+
+impl<T, I> Binders<Binders<T>>
+where
+ T: TypeFoldable<I> + HasInterner<Interner = I>,
+ I: Interner,
+{
+ /// This turns two levels of binders (`for<A> for<B>`) into one level (`for<A, B>`).
+ pub fn fuse_binders(self, interner: T::Interner) -> Binders<T> {
+ let num_binders = self.len(interner);
+ // generate a substitution to shift the indexes of the inner binder:
+ let subst = Substitution::from_iter(
+ interner,
+ self.value
+ .binders
+ .iter(interner)
+ .enumerate()
+ .map(|(i, pk)| (i + num_binders, pk).to_generic_arg(interner)),
+ );
+ let binders = VariableKinds::from_iter(
+ interner,
+ self.binders
+ .iter(interner)
+ .chain(self.value.binders.iter(interner))
+ .cloned(),
+ );
+ let value = self.value.substitute(interner, &subst);
+ Binders { binders, value }
+ }
+}
+
+impl<T: HasInterner> From<Binders<T>> for (VariableKinds<T::Interner>, T) {
+ fn from(binders: Binders<T>) -> Self {
+ (binders.binders, binders.value)
+ }
+}
+
+impl<T, I> Binders<T>
+where
+ T: TypeFoldable<I> + HasInterner<Interner = I>,
+ I: Interner,
+{
+ /// Substitute `parameters` for the variables introduced by these
+ /// binders. So if the binders represent (e.g.) `<X, Y> { T }` and
+ /// parameters is the slice `[A, B]`, then returns `[X => A, Y =>
+ /// B] T`.
+ pub fn substitute(self, interner: I, parameters: &(impl AsParameters<I> + ?Sized)) -> T {
+ let parameters = parameters.as_parameters(interner);
+ assert_eq!(self.binders.len(interner), parameters.len());
+ Subst::apply(interner, parameters, self.value)
+ }
+}
+
+/// Allows iterating over a Binders<Vec<T>>, for instance.
+/// Each element will include the same set of parameter bounds.
+impl<V, U> IntoIterator for Binders<V>
+where
+ V: HasInterner + IntoIterator<Item = U>,
+ U: HasInterner<Interner = V::Interner>,
+{
+ type Item = Binders<U>;
+ type IntoIter = BindersIntoIterator<V>;
+
+ fn into_iter(self) -> Self::IntoIter {
+ BindersIntoIterator {
+ iter: self.value.into_iter(),
+ binders: self.binders,
+ }
+ }
+}
+
+/// `IntoIterator` for binders.
+pub struct BindersIntoIterator<V: HasInterner + IntoIterator> {
+ iter: <V as IntoIterator>::IntoIter,
+ binders: VariableKinds<V::Interner>,
+}
+
+impl<V> Iterator for BindersIntoIterator<V>
+where
+ V: HasInterner + IntoIterator,
+ <V as IntoIterator>::Item: HasInterner<Interner = V::Interner>,
+{
+ type Item = Binders<<V as IntoIterator>::Item>;
+ fn next(&mut self) -> Option<Self::Item> {
+ self.iter
+ .next()
+ .map(|v| Binders::new(self.binders.clone(), v))
+ }
+}
+
+/// Represents one clause of the form `consequence :- conditions` where
+/// `conditions = cond_1 && cond_2 && ...` is the conjunction of the individual
+/// conditions.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub struct ProgramClauseImplication<I: Interner> {
+ /// The consequence of the clause, which holds if the conditions holds.
+ pub consequence: DomainGoal<I>,
+
+ /// The condition goals that should hold.
+ pub conditions: Goals<I>,
+
+ /// The lifetime constraints that should be proven.
+ pub constraints: Constraints<I>,
+
+ /// The relative priority of the implication.
+ pub priority: ClausePriority,
+}
+
+/// Specifies how important an implication is.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+pub enum ClausePriority {
+ /// High priority, the solver should prioritize this.
+ High,
+
+ /// Low priority, this implication has lower chance to be relevant to the goal.
+ Low,
+}
+
+impl std::ops::BitAnd for ClausePriority {
+ type Output = ClausePriority;
+ fn bitand(self, rhs: ClausePriority) -> Self::Output {
+ match (self, rhs) {
+ (ClausePriority::High, ClausePriority::High) => ClausePriority::High,
+ _ => ClausePriority::Low,
+ }
+ }
+}
+
+/// Contains the data for a program clause.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, HasInterner, Zip)]
+pub struct ProgramClauseData<I: Interner>(pub Binders<ProgramClauseImplication<I>>);
+
+impl<I: Interner> ProgramClauseImplication<I> {
+ /// Change the implication into an application holding a `FromEnv` goal.
+ pub fn into_from_env_clause(self, interner: I) -> ProgramClauseImplication<I> {
+ if self.conditions.is_empty(interner) {
+ ProgramClauseImplication {
+ consequence: self.consequence.into_from_env_goal(interner),
+ conditions: self.conditions.clone(),
+ constraints: self.constraints.clone(),
+ priority: self.priority,
+ }
+ } else {
+ self
+ }
+ }
+}
+
+impl<I: Interner> ProgramClauseData<I> {
+ /// Change the program clause data into a `FromEnv` program clause.
+ pub fn into_from_env_clause(self, interner: I) -> ProgramClauseData<I> {
+ ProgramClauseData(self.0.map(|i| i.into_from_env_clause(interner)))
+ }
+
+ /// Intern the program clause data.
+ pub fn intern(self, interner: I) -> ProgramClause<I> {
+ ProgramClause {
+ interned: interner.intern_program_clause(self),
+ }
+ }
+}
+
+/// A program clause is a logic expression used to describe a part of the program.
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+pub struct ProgramClause<I: Interner> {
+ interned: I::InternedProgramClause,
+}
+
+impl<I: Interner> ProgramClause<I> {
+ /// Create a new program clause using `ProgramClauseData`.
+ pub fn new(interner: I, clause: ProgramClauseData<I>) -> Self {
+ let interned = interner.intern_program_clause(clause);
+ Self { interned }
+ }
+
+ /// Change the clause into a `FromEnv` clause.
+ pub fn into_from_env_clause(self, interner: I) -> ProgramClause<I> {
+ let program_clause_data = self.data(interner);
+ let new_clause = program_clause_data.clone().into_from_env_clause(interner);
+ Self::new(interner, new_clause)
+ }
+
+ /// Get the interned program clause.
+ pub fn interned(&self) -> &I::InternedProgramClause {
+ &self.interned
+ }
+
+ /// Get the program clause data.
+ pub fn data(&self, interner: I) -> &ProgramClauseData<I> {
+ interner.program_clause_data(&self.interned)
+ }
+}
+
+/// Wraps a "canonicalized item". Items are canonicalized as follows:
+///
+/// All unresolved existential variables are "renumbered" according to their
+/// first appearance; the kind/universe of the variable is recorded in the
+/// `binders` field.
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct Canonical<T: HasInterner> {
+ /// The item that is canonicalized.
+ pub value: T,
+
+ /// The kind/universe of the variable.
+ pub binders: CanonicalVarKinds<T::Interner>,
+}
+
+impl<T: HasInterner> HasInterner for Canonical<T> {
+ type Interner = T::Interner;
+}
+
+/// A "universe canonical" value. This is a wrapper around a
+/// `Canonical`, indicating that the universes within have been
+/// "renumbered" to start from 0 and collapse unimportant
+/// distinctions.
+///
+/// To produce one of these values, use the `u_canonicalize` method.
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub struct UCanonical<T: HasInterner> {
+ /// The wrapped `Canonical`.
+ pub canonical: Canonical<T>,
+
+ /// The number of universes that have been collapsed.
+ pub universes: usize,
+}
+
+impl<T: HasInterner> UCanonical<T> {
+ /// Checks whether the universe canonical value is a trivial
+ /// substitution (e.g. an identity substitution).
+ pub fn is_trivial_substitution(
+ &self,
+ interner: T::Interner,
+ canonical_subst: &Canonical<AnswerSubst<T::Interner>>,
+ ) -> bool {
+ let subst = &canonical_subst.value.subst;
+ assert_eq!(
+ self.canonical.binders.len(interner),
+ subst.as_slice(interner).len()
+ );
+ subst.is_identity_subst(interner)
+ }
+
+ /// Creates an identity substitution.
+ pub fn trivial_substitution(&self, interner: T::Interner) -> Substitution<T::Interner> {
+ let binders = &self.canonical.binders;
+ Substitution::from_iter(
+ interner,
+ binders
+ .iter(interner)
+ .enumerate()
+ .map(|(index, pk)| {
+ let bound_var = BoundVar::new(DebruijnIndex::INNERMOST, index);
+ match &pk.kind {
+ VariableKind::Ty(_) => {
+ GenericArgData::Ty(TyKind::BoundVar(bound_var).intern(interner))
+ .intern(interner)
+ }
+ VariableKind::Lifetime => GenericArgData::Lifetime(
+ LifetimeData::BoundVar(bound_var).intern(interner),
+ )
+ .intern(interner),
+ VariableKind::Const(ty) => GenericArgData::Const(
+ ConstData {
+ ty: ty.clone(),
+ value: ConstValue::BoundVar(bound_var),
+ }
+ .intern(interner),
+ )
+ .intern(interner),
+ }
+ })
+ .collect::<Vec<_>>(),
+ )
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+/// A general goal; this is the full range of questions you can pose to Chalk.
+pub struct Goal<I: Interner> {
+ interned: I::InternedGoal,
+}
+
+impl<I: Interner> Goal<I> {
+ /// Create a new goal using `GoalData`.
+ pub fn new(interner: I, interned: GoalData<I>) -> Self {
+ let interned = I::intern_goal(interner, interned);
+ Self { interned }
+ }
+
+ /// Gets the interned goal.
+ pub fn interned(&self) -> &I::InternedGoal {
+ &self.interned
+ }
+
+ /// Gets the interned goal data.
+ pub fn data(&self, interner: I) -> &GoalData<I> {
+ interner.goal_data(&self.interned)
+ }
+
+ /// Create a goal using a `forall` or `exists` quantifier.
+ pub fn quantify(self, interner: I, kind: QuantifierKind, binders: VariableKinds<I>) -> Goal<I> {
+ GoalData::Quantified(kind, Binders::new(binders, self)).intern(interner)
+ }
+
+ /// Takes a goal `G` and turns it into `not { G }`.
+ pub fn negate(self, interner: I) -> Self {
+ GoalData::Not(self).intern(interner)
+ }
+
+ /// Takes a goal `G` and turns it into `compatible { G }`.
+ pub fn compatible(self, interner: I) -> Self {
+ // compatible { G } desugars into: forall<T> { if (Compatible, DownstreamType(T)) { G } }
+ // This activates the compatible modality rules and introduces an anonymous downstream type
+ GoalData::Quantified(
+ QuantifierKind::ForAll,
+ Binders::with_fresh_type_var(interner, |ty| {
+ GoalData::Implies(
+ ProgramClauses::from_iter(
+ interner,
+ vec![DomainGoal::Compatible, DomainGoal::DownstreamType(ty)],
+ ),
+ self.shifted_in(interner),
+ )
+ .intern(interner)
+ }),
+ )
+ .intern(interner)
+ }
+
+ /// Create an implication goal that holds if the predicates are true.
+ pub fn implied_by(self, interner: I, predicates: ProgramClauses<I>) -> Goal<I> {
+ GoalData::Implies(predicates, self).intern(interner)
+ }
+
+ /// True if this goal is "trivially true" -- i.e., no work is
+ /// required to prove it.
+ pub fn is_trivially_true(&self, interner: I) -> bool {
+ match self.data(interner) {
+ GoalData::All(goals) => goals.is_empty(interner),
+ _ => false,
+ }
+ }
+}
+
+impl<I> Goal<I>
+where
+ I: Interner,
+{
+ /// Creates a single goal that only holds if a list of goals holds.
+ pub fn all<II>(interner: I, iter: II) -> Self
+ where
+ II: IntoIterator<Item = Goal<I>>,
+ {
+ let mut iter = iter.into_iter();
+ if let Some(goal0) = iter.next() {
+ if let Some(goal1) = iter.next() {
+ // More than one goal to prove
+ let goals = Goals::from_iter(
+ interner,
+ Some(goal0).into_iter().chain(Some(goal1)).chain(iter),
+ );
+ GoalData::All(goals).intern(interner)
+ } else {
+ // One goal to prove
+ goal0
+ }
+ } else {
+ // No goals to prove, always true
+ GoalData::All(Goals::empty(interner)).intern(interner)
+ }
+ }
+}
+
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+/// A general goal; this is the full range of questions you can pose to Chalk.
+pub enum GoalData<I: Interner> {
+ /// Introduces a binding at depth 0, shifting other bindings up
+ /// (deBruijn index).
+ Quantified(QuantifierKind, Binders<Goal<I>>),
+
+ /// A goal that holds given some clauses (like an if-statement).
+ Implies(ProgramClauses<I>, Goal<I>),
+
+ /// List of goals that all should hold.
+ All(Goals<I>),
+
+ /// Negation: the inner goal should not hold.
+ Not(Goal<I>),
+
+ /// Make two things equal; the rules for doing so are well known to the logic
+ EqGoal(EqGoal<I>),
+
+ /// Make one thing a subtype of another; the rules for doing so are well known to the logic
+ SubtypeGoal(SubtypeGoal<I>),
+
+ /// A "domain goal" indicates some base sort of goal that can be
+ /// proven via program clauses
+ DomainGoal(DomainGoal<I>),
+
+ /// Indicates something that cannot be proven to be true or false
+ /// definitively. This can occur with overflow but also with
+ /// unifications of skolemized variables like `forall<X,Y> { X = Y
+ /// }`. Of course, that statement is false, as there exist types
+ /// X, Y where `X = Y` is not true. But we treat it as "cannot
+ /// prove" so that `forall<X,Y> { not { X = Y } }` also winds up
+ /// as cannot prove.
+ CannotProve,
+}
+
+impl<I: Interner> Copy for GoalData<I>
+where
+ I::InternedType: Copy,
+ I::InternedLifetime: Copy,
+ I::InternedGenericArg: Copy,
+ I::InternedSubstitution: Copy,
+ I::InternedGoal: Copy,
+ I::InternedGoals: Copy,
+ I::InternedProgramClauses: Copy,
+ I::InternedVariableKinds: Copy,
+{
+}
+
+impl<I: Interner> GoalData<I> {
+ /// Create an interned goal.
+ pub fn intern(self, interner: I) -> Goal<I> {
+ Goal::new(interner, self)
+ }
+}
+
+/// Kinds of quantifiers in the logic, such as `forall` and `exists`.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub enum QuantifierKind {
+ /// Universal quantifier `ForAll`.
+ ///
+ /// A formula with the universal quantifier `forall(x). P(x)` is satisfiable
+ /// if and only if the subformula `P(x)` is true for all possible values for x.
+ ForAll,
+
+ /// Existential quantifier `Exists`.
+ ///
+ /// A formula with the existential quantifier `exists(x). P(x)` is satisfiable
+ /// if and only if there exists at least one value for all possible values of x
+ /// which satisfies the subformula `P(x)`.
+
+ /// In the context of chalk, the existential quantifier usually demands the
+ /// existence of exactly one instance (i.e. type) that satisfies the formula
+ /// (i.e. type constraints). More than one instance means that the result is ambiguous.
+ Exists,
+}
+
+/// A constraint on lifetimes.
+///
+/// When we search for solutions within the trait system, we essentially ignore
+/// lifetime constraints, instead gathering them up to return with our solution
+/// for later checking. This allows for decoupling between type and region
+/// checking in the compiler.
+#[derive(Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner, Zip)]
+pub enum Constraint<I: Interner> {
+ /// Outlives constraint `'a: 'b`, indicating that the value of `'a` must be
+ /// a superset of the value of `'b`.
+ LifetimeOutlives(Lifetime<I>, Lifetime<I>),
+
+ /// Type outlives constraint `T: 'a`, indicating that the type `T` must live
+ /// at least as long as the value of `'a`.
+ TypeOutlives(Ty<I>, Lifetime<I>),
+}
+
+impl<I: Interner> Copy for Constraint<I>
+where
+ I::InternedLifetime: Copy,
+ I::InternedType: Copy,
+{
+}
+
+impl<I: Interner> Substitution<I> {
+ /// A substitution is an **identity substitution** if it looks
+ /// like this
+ ///
+ /// ```text
+ /// ?0 := ?0
+ /// ?1 := ?1
+ /// ?2 := ?2
+ /// ...
+ /// ```
+ ///
+ /// Basically, each value is mapped to a type or lifetime with its
+ /// same index.
+ pub fn is_identity_subst(&self, interner: I) -> bool {
+ self.iter(interner).zip(0..).all(|(generic_arg, index)| {
+ let index_db = BoundVar::new(DebruijnIndex::INNERMOST, index);
+ match generic_arg.data(interner) {
+ GenericArgData::Ty(ty) => match ty.kind(interner) {
+ TyKind::BoundVar(depth) => index_db == *depth,
+ _ => false,
+ },
+ GenericArgData::Lifetime(lifetime) => match lifetime.data(interner) {
+ LifetimeData::BoundVar(depth) => index_db == *depth,
+ _ => false,
+ },
+ GenericArgData::Const(constant) => match &constant.data(interner).value {
+ ConstValue::BoundVar(depth) => index_db == *depth,
+ _ => false,
+ },
+ }
+ })
+ }
+
+ /// Apply the substitution to a value.
+ pub fn apply<T>(&self, value: T, interner: I) -> T
+ where
+ T: TypeFoldable<I>,
+ {
+ Substitute::apply(self, value, interner)
+ }
+
+ /// Gets an iterator of all type parameters.
+ pub fn type_parameters(&self, interner: I) -> impl Iterator<Item = Ty<I>> + '_ {
+ self.iter(interner)
+ .filter_map(move |p| p.ty(interner))
+ .cloned()
+ }
+
+ /// Compute type flags for Substitution<I>
+ fn compute_flags(&self, interner: I) -> TypeFlags {
+ let mut flags = TypeFlags::empty();
+ for generic_arg in self.iter(interner) {
+ flags |= generic_arg.compute_flags(interner);
+ }
+ flags
+ }
+}
+
+#[derive(FallibleTypeFolder)]
+struct SubstFolder<'i, I: Interner, A: AsParameters<I>> {
+ interner: I,
+ subst: &'i A,
+}
+
+impl<I: Interner, A: AsParameters<I>> SubstFolder<'_, I, A> {
+ /// Index into the list of parameters.
+ pub fn at(&self, index: usize) -> &GenericArg<I> {
+ let interner = self.interner;
+ &self.subst.as_parameters(interner)[index]
+ }
+}
+
+/// Convert a value to a list of parameters.
+pub trait AsParameters<I: Interner> {
+ /// Convert the current value to parameters.
+ fn as_parameters(&self, interner: I) -> &[GenericArg<I>];
+}
+
+impl<I: Interner> AsParameters<I> for Substitution<I> {
+ #[allow(unreachable_code, unused_variables)]
+ fn as_parameters(&self, interner: I) -> &[GenericArg<I>] {
+ self.as_slice(interner)
+ }
+}
+
+impl<I: Interner> AsParameters<I> for [GenericArg<I>] {
+ fn as_parameters(&self, _interner: I) -> &[GenericArg<I>] {
+ self
+ }
+}
+
+impl<I: Interner> AsParameters<I> for [GenericArg<I>; 1] {
+ fn as_parameters(&self, _interner: I) -> &[GenericArg<I>] {
+ self
+ }
+}
+
+impl<I: Interner> AsParameters<I> for Vec<GenericArg<I>> {
+ fn as_parameters(&self, _interner: I) -> &[GenericArg<I>] {
+ self
+ }
+}
+
+impl<T, I: Interner> AsParameters<I> for &T
+where
+ T: ?Sized + AsParameters<I>,
+{
+ fn as_parameters(&self, interner: I) -> &[GenericArg<I>] {
+ T::as_parameters(self, interner)
+ }
+}
+
+/// An extension trait to anything that can be represented as list of `GenericArg`s that signifies
+/// that it can applied as a substituion to a value
+pub trait Substitute<I: Interner>: AsParameters<I> {
+ /// Apply the substitution to a value.
+ fn apply<T: TypeFoldable<I>>(&self, value: T, interner: I) -> T;
+}
+
+impl<I: Interner, A: AsParameters<I>> Substitute<I> for A {
+ fn apply<T>(&self, value: T, interner: I) -> T
+ where
+ T: TypeFoldable<I>,
+ {
+ value
+ .try_fold_with(
+ &mut SubstFolder {
+ interner,
+ subst: self,
+ },
+ DebruijnIndex::INNERMOST,
+ )
+ .unwrap()
+ }
+}
+
+/// Utility for converting a list of all the binders into scope
+/// into references to those binders. Simply pair the binders with
+/// the indices, and invoke `to_generic_arg()` on the `(binder,
+/// index)` pair. The result will be a reference to a bound
+/// variable of appropriate kind at the corresponding index.
+pub trait ToGenericArg<I: Interner> {
+ /// Converts the binders in scope to references to those binders.
+ fn to_generic_arg(&self, interner: I) -> GenericArg<I> {
+ self.to_generic_arg_at_depth(interner, DebruijnIndex::INNERMOST)
+ }
+
+ /// Converts the binders at the specified depth to references to those binders.
+ fn to_generic_arg_at_depth(&self, interner: I, debruijn: DebruijnIndex) -> GenericArg<I>;
+}
+
+impl<'a, I: Interner> ToGenericArg<I> for (usize, &'a VariableKind<I>) {
+ fn to_generic_arg_at_depth(&self, interner: I, debruijn: DebruijnIndex) -> GenericArg<I> {
+ let &(index, binder) = self;
+ let bound_var = BoundVar::new(debruijn, index);
+ binder.to_bound_variable(interner, bound_var)
+ }
+}
+
+impl<'i, I: Interner, A: AsParameters<I>> TypeFolder<I> for SubstFolder<'i, I, A> {
+ fn as_dyn(&mut self) -> &mut dyn TypeFolder<I> {
+ self
+ }
+
+ fn fold_free_var_ty(&mut self, bound_var: BoundVar, outer_binder: DebruijnIndex) -> Ty<I> {
+ assert_eq!(bound_var.debruijn, DebruijnIndex::INNERMOST);
+ let ty = self.at(bound_var.index);
+ let ty = ty.assert_ty_ref(TypeFolder::interner(self));
+ ty.clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder)
+ }
+
+ fn fold_free_var_lifetime(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Lifetime<I> {
+ assert_eq!(bound_var.debruijn, DebruijnIndex::INNERMOST);
+ let l = self.at(bound_var.index);
+ let l = l.assert_lifetime_ref(TypeFolder::interner(self));
+ l.clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder)
+ }
+
+ fn fold_free_var_const(
+ &mut self,
+ _ty: Ty<I>,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> Const<I> {
+ assert_eq!(bound_var.debruijn, DebruijnIndex::INNERMOST);
+ let c = self.at(bound_var.index);
+ let c = c.assert_const_ref(TypeFolder::interner(self));
+ c.clone()
+ .shifted_in_from(TypeFolder::interner(self), outer_binder)
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+}
+
+macro_rules! interned_slice_common {
+ ($seq:ident, $data:ident => $elem:ty, $intern:ident => $interned:ident) => {
+ /// List of interned elements.
+ #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, HasInterner)]
+ pub struct $seq<I: Interner> {
+ interned: I::$interned,
+ }
+
+ impl<I: Interner> $seq<I> {
+ /// Get the interned elements.
+ pub fn interned(&self) -> &I::$interned {
+ &self.interned
+ }
+
+ /// Returns a slice containing the elements.
+ pub fn as_slice(&self, interner: I) -> &[$elem] {
+ Interner::$data(interner, &self.interned)
+ }
+
+ /// Index into the sequence.
+ pub fn at(&self, interner: I, index: usize) -> &$elem {
+ &self.as_slice(interner)[index]
+ }
+
+ /// Create an empty sequence.
+ pub fn empty(interner: I) -> Self {
+ Self::from_iter(interner, None::<$elem>)
+ }
+
+ /// Check whether this is an empty sequence.
+ pub fn is_empty(&self, interner: I) -> bool {
+ self.as_slice(interner).is_empty()
+ }
+
+ /// Get an iterator over the elements of the sequence.
+ pub fn iter(&self, interner: I) -> std::slice::Iter<'_, $elem> {
+ self.as_slice(interner).iter()
+ }
+
+ /// Get the length of the sequence.
+ pub fn len(&self, interner: I) -> usize {
+ self.as_slice(interner).len()
+ }
+ }
+ };
+}
+
+macro_rules! interned_slice {
+ ($seq:ident, $data:ident => $elem:ty, $intern:ident => $interned:ident) => {
+ interned_slice_common!($seq, $data => $elem, $intern => $interned);
+
+ impl<I: Interner> $seq<I> {
+ /// Tries to create a sequence using an iterator of element-like things.
+ pub fn from_fallible<E>(
+ interner: I,
+ elements: impl IntoIterator<Item = Result<impl CastTo<$elem>, E>>,
+ ) -> Result<Self, E> {
+ Ok(Self {
+ interned: I::$intern(interner, elements.into_iter().casted(interner))?,
+ })
+ }
+
+ /// Create a sequence from elements
+ pub fn from_iter(
+ interner: I,
+ elements: impl IntoIterator<Item = impl CastTo<$elem>>,
+ ) -> Self {
+ Self::from_fallible(
+ interner,
+ elements
+ .into_iter()
+ .map(|el| -> Result<$elem, ()> { Ok(el.cast(interner)) }),
+ )
+ .unwrap()
+ }
+
+ /// Create a sequence from a single element.
+ pub fn from1(interner: I, element: impl CastTo<$elem>) -> Self {
+ Self::from_iter(interner, Some(element))
+ }
+ }
+ };
+}
+
+interned_slice!(
+ QuantifiedWhereClauses,
+ quantified_where_clauses_data => QuantifiedWhereClause<I>,
+ intern_quantified_where_clauses => InternedQuantifiedWhereClauses
+);
+
+interned_slice!(
+ ProgramClauses,
+ program_clauses_data => ProgramClause<I>,
+ intern_program_clauses => InternedProgramClauses
+);
+
+interned_slice!(
+ VariableKinds,
+ variable_kinds_data => VariableKind<I>,
+ intern_generic_arg_kinds => InternedVariableKinds
+);
+
+interned_slice!(
+ CanonicalVarKinds,
+ canonical_var_kinds_data => CanonicalVarKind<I>,
+ intern_canonical_var_kinds => InternedCanonicalVarKinds
+);
+
+interned_slice!(Goals, goals_data => Goal<I>, intern_goals => InternedGoals);
+
+interned_slice!(
+ Constraints,
+ constraints_data => InEnvironment<Constraint<I>>,
+ intern_constraints => InternedConstraints
+);
+
+interned_slice!(
+ Substitution,
+ substitution_data => GenericArg<I>,
+ intern_substitution => InternedSubstitution
+);
+
+interned_slice_common!(
+ Variances,
+ variances_data => Variance,
+ intern_variance => InternedVariances
+);
+
+impl<I: Interner> Variances<I> {
+ /// Tries to create a list of canonical variable kinds using an iterator.
+ pub fn from_fallible<E>(
+ interner: I,
+ variances: impl IntoIterator<Item = Result<Variance, E>>,
+ ) -> Result<Self, E> {
+ Ok(Variances {
+ interned: I::intern_variances(interner, variances.into_iter())?,
+ })
+ }
+
+ /// Creates a list of canonical variable kinds using an iterator.
+ pub fn from_iter(interner: I, variances: impl IntoIterator<Item = Variance>) -> Self {
+ Self::from_fallible(
+ interner,
+ variances
+ .into_iter()
+ .map(|p| -> Result<Variance, ()> { Ok(p) }),
+ )
+ .unwrap()
+ }
+
+ /// Creates a list of canonical variable kinds from a single canonical variable kind.
+ pub fn from1(interner: I, variance: Variance) -> Self {
+ Self::from_iter(interner, Some(variance))
+ }
+}
+
+/// Combines a substitution (`subst`) with a set of region constraints
+/// (`constraints`). This represents the result of a query; the
+/// substitution stores the values for the query's unknown variables,
+/// and the constraints represents any region constraints that must
+/// additionally be solved.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct ConstrainedSubst<I: Interner> {
+ /// The substitution that is being constrained.
+ ///
+ /// NB: The `is_trivial` routine relies on the fact that `subst` is folded first.
+ pub subst: Substitution<I>,
+
+ /// Region constraints that constrain the substitution.
+ pub constraints: Constraints<I>,
+}
+
+/// The resulting substitution after solving a goal.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable, HasInterner)]
+pub struct AnswerSubst<I: Interner> {
+ /// The substitution result.
+ ///
+ /// NB: The `is_trivial` routine relies on the fact that `subst` is folded first.
+ pub subst: Substitution<I>,
+
+ /// List of constraints that are part of the answer.
+ pub constraints: Constraints<I>,
+
+ /// Delayed subgoals, used when the solver answered with an (incomplete) `Answer` (instead of a `CompleteAnswer`).
+ pub delayed_subgoals: Vec<InEnvironment<Goal<I>>>,
+}
+
+/// Logic to decide the Variance for a given subst
+pub trait UnificationDatabase<I>
+where
+ Self: std::fmt::Debug,
+ I: Interner,
+{
+ /// Gets the variances for the substitution of a fn def
+ fn fn_def_variance(&self, fn_def_id: FnDefId<I>) -> Variances<I>;
+
+ /// Gets the variances for the substitution of a adt
+ fn adt_variance(&self, adt_id: AdtId<I>) -> Variances<I>;
+}
diff --git a/vendor/chalk-ir/src/visit.rs b/vendor/chalk-ir/src/visit.rs
new file mode 100644
index 000000000..c761ab46f
--- /dev/null
+++ b/vendor/chalk-ir/src/visit.rs
@@ -0,0 +1,422 @@
+//! Traits for visiting bits of IR.
+use std::fmt::Debug;
+use std::ops::ControlFlow;
+
+use crate::{
+ BoundVar, Const, ConstValue, DebruijnIndex, DomainGoal, Goal, InferenceVar, Interner, Lifetime,
+ LifetimeData, PlaceholderIndex, ProgramClause, Ty, TyKind, WhereClause,
+};
+
+mod binder_impls;
+mod boring_impls;
+pub mod visitors;
+
+pub use visitors::VisitExt;
+
+/// Unwraps a `ControlFlow` or propagates its `Break` value.
+/// This replaces the `Try` implementation that would be used
+/// with `std::ops::ControlFlow`.
+#[macro_export]
+macro_rules! try_break {
+ ($expr:expr) => {
+ match $expr {
+ std::ops::ControlFlow::Continue(c) => c,
+ std::ops::ControlFlow::Break(b) => return std::ops::ControlFlow::Break(b),
+ }
+ };
+}
+
+/// A "visitor" recursively folds some term -- that is, some bit of IR,
+/// such as a `Goal`, and computes a value as a result.
+///
+///
+/// To **apply** a visitor, use the `TypeVisitable::visit_with` method, like so
+///
+/// ```rust,ignore
+/// let result = x.visit_with(&mut visitor, 0);
+/// ```
+pub trait TypeVisitor<I: Interner> {
+ /// The "break type" of the visitor, often `()`. It represents the result
+ /// the visitor yields when it stops visiting.
+ type BreakTy;
+
+ /// Creates a `dyn` value from this visitor. Unfortunately, this
+ /// must be added manually to each impl of visitor; it permits the
+ /// default implements below to create a `&mut dyn TypeVisitor` from
+ /// `Self` without knowing what `Self` is (by invoking this
+ /// method). Effectively, this limits impls of `visitor` to types
+ /// for which we are able to create a dyn value (i.e., not `[T]`
+ /// types).
+ fn as_dyn(&mut self) -> &mut dyn TypeVisitor<I, BreakTy = Self::BreakTy>;
+
+ /// Top-level callback: invoked for each `Ty<I>` that is
+ /// encountered when visiting. By default, invokes
+ /// `super_visit_with`, which will in turn invoke the more
+ /// specialized visiting methods below, like `visit_free_var`.
+ fn visit_ty(&mut self, ty: &Ty<I>, outer_binder: DebruijnIndex) -> ControlFlow<Self::BreakTy> {
+ ty.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Lifetime<I>` that is
+ /// encountered when visiting. By default, invokes
+ /// `super_visit_with`, which will in turn invoke the more
+ /// specialized visiting methods below, like `visit_free_var`.
+ fn visit_lifetime(
+ &mut self,
+ lifetime: &Lifetime<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ lifetime.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Top-level callback: invoked for each `Const<I>` that is
+ /// encountered when visiting. By default, invokes
+ /// `super_visit_with`, which will in turn invoke the more
+ /// specialized visiting methods below, like `visit_free_var`.
+ fn visit_const(
+ &mut self,
+ constant: &Const<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ constant.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Invoked for every program clause. By default, recursively visits the goals contents.
+ fn visit_program_clause(
+ &mut self,
+ clause: &ProgramClause<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ clause.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Invoked for every goal. By default, recursively visits the goals contents.
+ fn visit_goal(
+ &mut self,
+ goal: &Goal<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ goal.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// Invoked for each domain goal.
+ fn visit_domain_goal(
+ &mut self,
+ domain_goal: &DomainGoal<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ domain_goal.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// If overridden to return true, then visiting will panic if a
+ /// free variable is encountered. This should be done if free
+ /// type/lifetime/const variables are not expected.
+ fn forbid_free_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for `BoundVar` instances that are not bound
+ /// within the type being visited over:
+ fn visit_free_var(
+ &mut self,
+ bound_var: BoundVar,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ if self.forbid_free_vars() {
+ panic!(
+ "unexpected free variable `{:?}` with outer binder {:?}",
+ bound_var, outer_binder
+ )
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+
+ /// If overridden to return true, we will panic when a free
+ /// placeholder type/lifetime is encountered.
+ fn forbid_free_placeholders(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a placeholder type; these are
+ /// used when we instantiate binders universally.
+ fn visit_free_placeholder(
+ &mut self,
+ universe: PlaceholderIndex,
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ if self.forbid_free_placeholders() {
+ panic!("unexpected placeholder type `{:?}`", universe)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+
+ /// Invoked for each where clause.
+ fn visit_where_clause(
+ &mut self,
+ where_clause: &WhereClause<I>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ where_clause.super_visit_with(self.as_dyn(), outer_binder)
+ }
+
+ /// If overridden to return true, inference variables will trigger
+ /// panics when visited. Used when inference variables are
+ /// unexpected.
+ fn forbid_inference_vars(&self) -> bool {
+ false
+ }
+
+ /// Invoked for each occurrence of a inference type; these are
+ /// used when we instantiate binders universally.
+ fn visit_inference_var(
+ &mut self,
+ var: InferenceVar,
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<Self::BreakTy> {
+ if self.forbid_inference_vars() {
+ panic!("unexpected inference type `{:?}`", var)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+
+ /// Gets the visitor's interner.
+ fn interner(&self) -> I;
+}
+
+/// Applies the given `visitor` to a value, producing a visited result
+/// of type `TypeVisitor::Result`.
+pub trait TypeVisitable<I: Interner>: Debug {
+ /// Apply the given visitor `visitor` to `self`; `binders` is the
+ /// number of binders that are in scope when beginning the
+ /// visitor. Typically `binders` starts as 0, but is adjusted when
+ /// we encounter `Binders<T>` in the IR or other similar
+ /// constructs.
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B>;
+}
+
+/// For types where "visit" invokes a callback on the `visitor`, the
+/// `TypeSuperVisitable` trait captures the recursive behavior that visits all
+/// the contents of the type.
+pub trait TypeSuperVisitable<I: Interner>: TypeVisitable<I> {
+ /// Recursively visits the type contents.
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B>;
+}
+
+/// "visiting" a type invokes the `visit_ty` method on the visitor; this
+/// usually (in turn) invokes `super_visit_ty` to visit the individual
+/// parts.
+impl<I: Interner> TypeVisitable<I> for Ty<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_ty(self, outer_binder)
+ }
+}
+
+/// "Super visit" for a type invokes the more detailed callbacks on the type
+impl<I> TypeSuperVisitable<I> for Ty<I>
+where
+ I: Interner,
+{
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ match self.kind(interner) {
+ TyKind::BoundVar(bound_var) => {
+ if bound_var.shifted_out_to(outer_binder).is_some() {
+ visitor.visit_free_var(*bound_var, outer_binder)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+ TyKind::Dyn(clauses) => clauses.visit_with(visitor, outer_binder),
+ TyKind::InferenceVar(var, _) => visitor.visit_inference_var(*var, outer_binder),
+ TyKind::Placeholder(ui) => visitor.visit_free_placeholder(*ui, outer_binder),
+ TyKind::Alias(proj) => proj.visit_with(visitor, outer_binder),
+ TyKind::Function(fun) => fun.visit_with(visitor, outer_binder),
+ TyKind::Adt(_id, substitution) => substitution.visit_with(visitor, outer_binder),
+ TyKind::AssociatedType(_assoc_ty, substitution) => {
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::Scalar(scalar) => scalar.visit_with(visitor, outer_binder),
+ TyKind::Str => ControlFlow::Continue(()),
+ TyKind::Tuple(arity, substitution) => {
+ try_break!(arity.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::OpaqueType(opaque_ty, substitution) => {
+ try_break!(opaque_ty.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::Slice(substitution) => substitution.visit_with(visitor, outer_binder),
+ TyKind::FnDef(fn_def, substitution) => {
+ try_break!(fn_def.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::Ref(mutability, lifetime, ty) => {
+ try_break!(mutability.visit_with(visitor, outer_binder));
+ try_break!(lifetime.visit_with(visitor, outer_binder));
+ ty.visit_with(visitor, outer_binder)
+ }
+ TyKind::Raw(mutability, ty) => {
+ try_break!(mutability.visit_with(visitor, outer_binder));
+ ty.visit_with(visitor, outer_binder)
+ }
+ TyKind::Never => ControlFlow::Continue(()),
+ TyKind::Array(ty, const_) => {
+ try_break!(ty.visit_with(visitor, outer_binder));
+ const_.visit_with(visitor, outer_binder)
+ }
+ TyKind::Closure(id, substitution) => {
+ try_break!(id.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::Generator(generator, substitution) => {
+ try_break!(generator.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::GeneratorWitness(witness, substitution) => {
+ try_break!(witness.visit_with(visitor, outer_binder));
+ substitution.visit_with(visitor, outer_binder)
+ }
+ TyKind::Foreign(foreign_ty) => foreign_ty.visit_with(visitor, outer_binder),
+ TyKind::Error => ControlFlow::Continue(()),
+ }
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Lifetime<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_lifetime(self, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeSuperVisitable<I> for Lifetime<I> {
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ match self.data(interner) {
+ LifetimeData::BoundVar(bound_var) => {
+ if bound_var.shifted_out_to(outer_binder).is_some() {
+ visitor.visit_free_var(*bound_var, outer_binder)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+ LifetimeData::InferenceVar(var) => visitor.visit_inference_var(*var, outer_binder),
+ LifetimeData::Placeholder(universe) => {
+ visitor.visit_free_placeholder(*universe, outer_binder)
+ }
+ LifetimeData::Static | LifetimeData::Erased => ControlFlow::Continue(()),
+ LifetimeData::Phantom(void, ..) => match *void {},
+ }
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Const<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_const(self, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeSuperVisitable<I> for Const<I> {
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ match &self.data(interner).value {
+ ConstValue::BoundVar(bound_var) => {
+ if bound_var.shifted_out_to(outer_binder).is_some() {
+ visitor.visit_free_var(*bound_var, outer_binder)
+ } else {
+ ControlFlow::Continue(())
+ }
+ }
+ ConstValue::InferenceVar(var) => visitor.visit_inference_var(*var, outer_binder),
+ ConstValue::Placeholder(universe) => {
+ visitor.visit_free_placeholder(*universe, outer_binder)
+ }
+ ConstValue::Concrete(_) => ControlFlow::Continue(()),
+ }
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Goal<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_goal(self, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeSuperVisitable<I> for Goal<I> {
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ self.data(interner).visit_with(visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for ProgramClause<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_program_clause(self, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for WhereClause<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_where_clause(self, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for DomainGoal<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visitor.visit_domain_goal(self, outer_binder)
+ }
+}
diff --git a/vendor/chalk-ir/src/visit/binder_impls.rs b/vendor/chalk-ir/src/visit/binder_impls.rs
new file mode 100644
index 000000000..709f99044
--- /dev/null
+++ b/vendor/chalk-ir/src/visit/binder_impls.rs
@@ -0,0 +1,47 @@
+//! This module contains impls of `TypeVisitable` for those types that
+//! introduce binders.
+//!
+//! The more interesting impls of `TypeVisitable` remain in the `visit` module.
+
+use crate::interner::HasInterner;
+use crate::{
+ Binders, Canonical, ControlFlow, DebruijnIndex, FnPointer, Interner, TypeVisitable, TypeVisitor,
+};
+
+impl<I: Interner> TypeVisitable<I> for FnPointer<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ self.substitution
+ .visit_with(visitor, outer_binder.shifted_in())
+ }
+}
+
+impl<T, I: Interner> TypeVisitable<I> for Binders<T>
+where
+ T: HasInterner + TypeVisitable<I>,
+{
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ self.value.visit_with(visitor, outer_binder.shifted_in())
+ }
+}
+
+impl<I, T> TypeVisitable<I> for Canonical<T>
+where
+ I: Interner,
+ T: HasInterner<Interner = I> + TypeVisitable<I>,
+{
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ self.value.visit_with(visitor, outer_binder.shifted_in())
+ }
+}
diff --git a/vendor/chalk-ir/src/visit/boring_impls.rs b/vendor/chalk-ir/src/visit/boring_impls.rs
new file mode 100644
index 000000000..512d9ecd8
--- /dev/null
+++ b/vendor/chalk-ir/src/visit/boring_impls.rs
@@ -0,0 +1,261 @@
+//! This module contains "rote and uninteresting" impls of `TypeVisitable` for
+//! various types. In general, we prefer to derive `TypeVisitable`, but
+//! sometimes that doesn't work for whatever reason.
+//!
+//! The more interesting impls of `TypeVisitable` remain in the `visit` module.
+
+use crate::{
+ try_break, AdtId, AssocTypeId, ClausePriority, ClosureId, Constraints, ControlFlow,
+ DebruijnIndex, FloatTy, FnDefId, ForeignDefId, GeneratorId, GenericArg, Goals, ImplId, IntTy,
+ Interner, Mutability, OpaqueTyId, PlaceholderIndex, ProgramClause, ProgramClauses,
+ QuantifiedWhereClauses, QuantifierKind, Safety, Scalar, Substitution, TraitId,
+ TypeSuperVisitable, TypeVisitable, TypeVisitor, UintTy, UniverseIndex,
+};
+use std::{marker::PhantomData, sync::Arc};
+
+/// Convenience function to visit all the items in the iterator it.
+pub fn visit_iter<'i, T, I, B>(
+ it: impl Iterator<Item = T>,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+) -> ControlFlow<B>
+where
+ T: TypeVisitable<I>,
+ I: 'i + Interner,
+{
+ for e in it {
+ try_break!(e.visit_with(visitor, outer_binder));
+ }
+ ControlFlow::Continue(())
+}
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for &T {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ T::visit_with(self, visitor, outer_binder)
+ }
+}
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for Vec<T> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visit_iter(self.iter(), visitor, outer_binder)
+ }
+}
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for &[T] {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ visit_iter(self.iter(), visitor, outer_binder)
+ }
+}
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for Box<T> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ T::visit_with(self, visitor, outer_binder)
+ }
+}
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for Arc<T> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ T::visit_with(self, visitor, outer_binder)
+ }
+}
+
+macro_rules! tuple_visit {
+ ($($n:ident),*) => {
+ impl<$($n: TypeVisitable<I>,)* I: Interner> TypeVisitable<I> for ($($n,)*) {
+ fn visit_with<BT>(&self, visitor: &mut dyn TypeVisitor<I, BreakTy = BT>, outer_binder: DebruijnIndex) -> ControlFlow<BT> {
+ #[allow(non_snake_case)]
+ let &($(ref $n),*) = self;
+ $(
+ try_break!($n.visit_with(visitor, outer_binder));
+ )*
+ ControlFlow::Continue(())
+ }
+ }
+ }
+}
+
+tuple_visit!(A, B);
+tuple_visit!(A, B, C);
+tuple_visit!(A, B, C, D);
+tuple_visit!(A, B, C, D, E);
+
+impl<T: TypeVisitable<I>, I: Interner> TypeVisitable<I> for Option<T> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ match self {
+ Some(e) => e.visit_with(visitor, outer_binder),
+ None => ControlFlow::Continue(()),
+ }
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for GenericArg<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ self.data(interner).visit_with(visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Substitution<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ visit_iter(self.iter(interner), visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Goals<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+ visit_iter(self.iter(interner), visitor, outer_binder)
+ }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! const_visit {
+ ($t:ty) => {
+ impl<I: Interner> $crate::visit::TypeVisitable<I> for $t {
+ fn visit_with<B>(
+ &self,
+ _visitor: &mut dyn ($crate::visit::TypeVisitor<I, BreakTy = B>),
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ ControlFlow::Continue(())
+ }
+ }
+ };
+}
+
+const_visit!(bool);
+const_visit!(usize);
+const_visit!(UniverseIndex);
+const_visit!(PlaceholderIndex);
+const_visit!(QuantifierKind);
+const_visit!(DebruijnIndex);
+const_visit!(ClausePriority);
+const_visit!(());
+const_visit!(Scalar);
+const_visit!(UintTy);
+const_visit!(IntTy);
+const_visit!(FloatTy);
+const_visit!(Mutability);
+const_visit!(Safety);
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! id_visit {
+ ($t:ident) => {
+ impl<I: Interner> $crate::visit::TypeVisitable<I> for $t<I> {
+ fn visit_with<B>(
+ &self,
+ _visitor: &mut dyn ($crate::visit::TypeVisitor<I, BreakTy = B>),
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ ControlFlow::Continue(())
+ }
+ }
+ };
+}
+
+id_visit!(ImplId);
+id_visit!(AdtId);
+id_visit!(TraitId);
+id_visit!(OpaqueTyId);
+id_visit!(AssocTypeId);
+id_visit!(FnDefId);
+id_visit!(ClosureId);
+id_visit!(GeneratorId);
+id_visit!(ForeignDefId);
+
+impl<I: Interner> TypeSuperVisitable<I> for ProgramClause<I> {
+ fn super_visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+
+ self.data(interner).0.visit_with(visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for ProgramClauses<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+
+ visit_iter(self.iter(interner), visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for Constraints<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+
+ visit_iter(self.iter(interner), visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for QuantifiedWhereClauses<I> {
+ fn visit_with<B>(
+ &self,
+ visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ let interner = visitor.interner();
+
+ visit_iter(self.iter(interner), visitor, outer_binder)
+ }
+}
+
+impl<I: Interner> TypeVisitable<I> for PhantomData<I> {
+ fn visit_with<B>(
+ &self,
+ _visitor: &mut dyn TypeVisitor<I, BreakTy = B>,
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<B> {
+ ControlFlow::Continue(())
+ }
+}
diff --git a/vendor/chalk-ir/src/visit/visitors.rs b/vendor/chalk-ir/src/visit/visitors.rs
new file mode 100644
index 000000000..51c087840
--- /dev/null
+++ b/vendor/chalk-ir/src/visit/visitors.rs
@@ -0,0 +1,41 @@
+//! TypeVisitor helpers
+
+use crate::{BoundVar, ControlFlow, DebruijnIndex, Interner, TypeVisitable, TypeVisitor};
+
+/// TypeVisitor extensions.
+pub trait VisitExt<I: Interner>: TypeVisitable<I> {
+ /// Check whether there are free (non-bound) variables.
+ fn has_free_vars(&self, interner: I) -> bool {
+ let flow = self.visit_with(
+ &mut FindFreeVarsVisitor { interner },
+ DebruijnIndex::INNERMOST,
+ );
+ matches!(flow, ControlFlow::Break(_))
+ }
+}
+
+impl<T, I: Interner> VisitExt<I> for T where T: TypeVisitable<I> {}
+
+struct FindFreeVarsVisitor<I: Interner> {
+ interner: I,
+}
+
+impl<I: Interner> TypeVisitor<I> for FindFreeVarsVisitor<I> {
+ type BreakTy = ();
+
+ fn as_dyn(&mut self) -> &mut dyn TypeVisitor<I, BreakTy = Self::BreakTy> {
+ self
+ }
+
+ fn interner(&self) -> I {
+ self.interner
+ }
+
+ fn visit_free_var(
+ &mut self,
+ _bound_var: BoundVar,
+ _outer_binder: DebruijnIndex,
+ ) -> ControlFlow<()> {
+ ControlFlow::Break(())
+ }
+}
diff --git a/vendor/chalk-ir/src/zip.rs b/vendor/chalk-ir/src/zip.rs
new file mode 100644
index 000000000..afa4a13cb
--- /dev/null
+++ b/vendor/chalk-ir/src/zip.rs
@@ -0,0 +1,543 @@
+//! Traits for "zipping" types, walking through two structures and checking that they match.
+
+use crate::fold::TypeFoldable;
+use crate::*;
+use std::fmt::Debug;
+use std::sync::Arc;
+
+/// When we zip types, we basically traverse the structure, ensuring
+/// that it matches. When we come to types/lifetimes, we invoke the
+/// callback methods in the zipper to match them up. Primarily used
+/// during unification or similar operations.
+///
+/// So e.g. if you had `A: Eq<B>` zipped with `X: Eq<Y>`, then the zipper
+/// would get two callbacks, one pairing `A` and `X`, and the other pairing
+/// `B` and `Y`.
+///
+/// For things other than types/lifetimes, the zip impls will
+/// guarantee equality. So e.g. if you have `A: Eq<B>` zipped with `X:
+/// Ord<Y>`, you would wind up with an error, no matter what zipper
+/// you are using. This is because the traits `Eq` and `Ord` are
+/// represented by two distinct `ItemId` values, and the impl for
+/// `ItemId` requires that all `ItemId` in the two zipped values match
+/// up.
+pub trait Zipper<I: Interner> {
+ /// Indicates that the two types `a` and `b` were found in matching spots.
+ fn zip_tys(&mut self, variance: Variance, a: &Ty<I>, b: &Ty<I>) -> Fallible<()>;
+
+ /// Indicates that the two lifetimes `a` and `b` were found in matching spots.
+ fn zip_lifetimes(
+ &mut self,
+ variance: Variance,
+ a: &Lifetime<I>,
+ b: &Lifetime<I>,
+ ) -> Fallible<()>;
+
+ /// Indicates that the two consts `a` and `b` were found in matching spots.
+ fn zip_consts(&mut self, variance: Variance, a: &Const<I>, b: &Const<I>) -> Fallible<()>;
+
+ /// Zips two values appearing beneath binders.
+ fn zip_binders<T>(
+ &mut self,
+ variance: Variance,
+ a: &Binders<T>,
+ b: &Binders<T>,
+ ) -> Fallible<()>
+ where
+ T: Clone + HasInterner<Interner = I> + Zip<I> + TypeFoldable<I>;
+
+ /// Zips two substs
+ fn zip_substs(
+ &mut self,
+ ambient: Variance,
+ variances: Option<Variances<I>>,
+ a: &[GenericArg<I>],
+ b: &[GenericArg<I>],
+ ) -> Fallible<()>
+ where
+ Self: Sized,
+ {
+ for (i, (a, b)) in a.iter().zip(b.iter()).enumerate() {
+ let variance = variances
+ .as_ref()
+ .map(|v| v.as_slice(self.interner())[i])
+ .unwrap_or(Variance::Invariant);
+ Zip::zip_with(self, ambient.xform(variance), a, b)?;
+ }
+ Ok(())
+ }
+
+ /// Retrieves the interner from the underlying zipper object
+ fn interner(&self) -> I;
+
+ /// Retrieves the `UnificationDatabase` from the underlying zipper object
+ fn unification_database(&self) -> &dyn UnificationDatabase<I>;
+}
+
+impl<'f, Z, I> Zipper<I> for &'f mut Z
+where
+ I: Interner,
+ Z: Zipper<I>,
+{
+ fn zip_tys(&mut self, variance: Variance, a: &Ty<I>, b: &Ty<I>) -> Fallible<()> {
+ (**self).zip_tys(variance, a, b)
+ }
+
+ fn zip_lifetimes(
+ &mut self,
+ variance: Variance,
+ a: &Lifetime<I>,
+ b: &Lifetime<I>,
+ ) -> Fallible<()> {
+ (**self).zip_lifetimes(variance, a, b)
+ }
+
+ fn zip_consts(&mut self, variance: Variance, a: &Const<I>, b: &Const<I>) -> Fallible<()> {
+ (**self).zip_consts(variance, a, b)
+ }
+
+ fn zip_binders<T>(&mut self, variance: Variance, a: &Binders<T>, b: &Binders<T>) -> Fallible<()>
+ where
+ T: Clone + HasInterner<Interner = I> + Zip<I> + TypeFoldable<I>,
+ {
+ (**self).zip_binders(variance, a, b)
+ }
+
+ fn interner(&self) -> I {
+ Z::interner(*self)
+ }
+
+ fn unification_database(&self) -> &dyn UnificationDatabase<I> {
+ (**self).unification_database()
+ }
+}
+
+/// The `Zip` trait walks two values, invoking the `Zipper` methods where
+/// appropriate, but otherwise requiring strict equality.
+///
+/// See `Zipper` trait for more details.
+///
+/// To implement the trait, typically you would use one of the macros
+/// like `eq_zip!`, `struct_zip!`, or `enum_zip!`.
+pub trait Zip<I>: Debug
+where
+ I: Interner,
+{
+ /// Uses the zipper to walk through two values, ensuring that they match.
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()>;
+}
+
+impl<'a, T: ?Sized + Zip<I>, I: Interner> Zip<I> for &'a T {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ <T as Zip<I>>::zip_with(zipper, variance, a, b)
+ }
+}
+
+impl<I: Interner> Zip<I> for () {
+ fn zip_with<Z: Zipper<I>>(_: &mut Z, _: Variance, _: &Self, _: &Self) -> Fallible<()> {
+ Ok(())
+ }
+}
+
+impl<T: Zip<I>, I: Interner> Zip<I> for Vec<T> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ <[T] as Zip<I>>::zip_with(zipper, variance, a, b)
+ }
+}
+
+impl<T: Zip<I>, I: Interner> Zip<I> for [T] {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ if a.len() != b.len() {
+ return Err(NoSolution);
+ }
+
+ for (a_elem, b_elem) in a.iter().zip(b) {
+ Zip::zip_with(zipper, variance, a_elem, b_elem)?;
+ }
+
+ Ok(())
+ }
+}
+
+impl<T: Zip<I>, I: Interner> Zip<I> for Arc<T> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ <T as Zip<I>>::zip_with(zipper, variance, a, b)
+ }
+}
+
+impl<T: Zip<I>, I: Interner> Zip<I> for Box<T> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ <T as Zip<I>>::zip_with(zipper, variance, a, b)
+ }
+}
+
+impl<T: Zip<I>, U: Zip<I>, I: Interner> Zip<I> for (T, U) {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ Zip::zip_with(zipper, variance, &a.0, &b.0)?;
+ Zip::zip_with(zipper, variance, &a.1, &b.1)?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for Ty<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ zipper.zip_tys(variance, a, b)
+ }
+}
+
+impl<I: Interner> Zip<I> for Lifetime<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ zipper.zip_lifetimes(variance, a, b)
+ }
+}
+
+impl<I: Interner> Zip<I> for Const<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ zipper.zip_consts(variance, a, b)
+ }
+}
+impl<I: Interner, T> Zip<I> for Binders<T>
+where
+ T: Clone + HasInterner<Interner = I> + Zip<I> + TypeFoldable<I>,
+{
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ zipper.zip_binders(variance, a, b)
+ }
+}
+
+/// Generates a Zip impl that requires the two values be
+/// equal. Suitable for atomic, scalar values.
+macro_rules! eq_zip {
+ ($I:ident => $t:ty) => {
+ impl<$I: Interner> Zip<$I> for $t {
+ fn zip_with<Z: Zipper<$I>>(
+ _zipper: &mut Z,
+ _variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ if a != b {
+ return Err(NoSolution);
+ }
+ Ok(())
+ }
+ }
+ };
+}
+
+eq_zip!(I => AdtId<I>);
+eq_zip!(I => TraitId<I>);
+eq_zip!(I => AssocTypeId<I>);
+eq_zip!(I => OpaqueTyId<I>);
+eq_zip!(I => GeneratorId<I>);
+eq_zip!(I => ForeignDefId<I>);
+eq_zip!(I => FnDefId<I>);
+eq_zip!(I => ClosureId<I>);
+eq_zip!(I => QuantifierKind);
+eq_zip!(I => PhantomData<I>);
+eq_zip!(I => PlaceholderIndex);
+eq_zip!(I => ClausePriority);
+eq_zip!(I => Mutability);
+eq_zip!(I => Scalar);
+
+impl<T: HasInterner<Interner = I> + Zip<I>, I: Interner> Zip<I> for InEnvironment<T> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ Zip::zip_with(zipper, variance, &a.environment, &b.environment)?;
+ Zip::zip_with(zipper, variance, &a.goal, &b.goal)?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for Environment<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ assert_eq!(a.clauses.len(interner), b.clauses.len(interner)); // or different numbers of clauses
+ Zip::zip_with(
+ zipper,
+ variance,
+ a.clauses.as_slice(interner),
+ b.clauses.as_slice(interner),
+ )?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for Goals<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.as_slice(interner), b.as_slice(interner))?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for ProgramClauses<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.as_slice(interner), b.as_slice(interner))?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for Constraints<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.as_slice(interner), b.as_slice(interner))?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for QuantifiedWhereClauses<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.as_slice(interner), b.as_slice(interner))?;
+ Ok(())
+ }
+}
+
+// Annoyingly, Goal cannot use `enum_zip` because some variants have
+// two parameters, and I'm too lazy to make the macro account for the
+// relevant name mangling.
+impl<I: Interner> Zip<I> for Goal<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.data(interner), b.data(interner))
+ }
+}
+
+// I'm too lazy to make `enum_zip` support type parameters.
+impl<I: Interner> Zip<I> for VariableKind<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ match (a, b) {
+ (VariableKind::Ty(a), VariableKind::Ty(b)) if a == b => Ok(()),
+ (VariableKind::Lifetime, VariableKind::Lifetime) => Ok(()),
+ (VariableKind::Const(ty_a), VariableKind::Const(ty_b)) => {
+ Zip::zip_with(zipper, variance, ty_a, ty_b)
+ }
+ (VariableKind::Ty(_), _)
+ | (VariableKind::Lifetime, _)
+ | (VariableKind::Const(_), _) => panic!("zipping things of mixed kind"),
+ }
+ }
+}
+
+impl<I: Interner> Zip<I> for GenericArg<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.data(interner), b.data(interner))
+ }
+}
+
+impl<I: Interner> Zip<I> for ProgramClause<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, a.data(interner), b.data(interner))
+ }
+}
+
+impl<I: Interner> Zip<I> for TraitRef<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, &a.trait_id, &b.trait_id)?;
+ zipper.zip_substs(
+ variance,
+ None,
+ a.substitution.as_slice(interner),
+ b.substitution.as_slice(interner),
+ )
+ }
+}
+
+impl<I: Interner> Zip<I> for ProjectionTy<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, &a.associated_ty_id, &b.associated_ty_id)?;
+ zipper.zip_substs(
+ variance,
+ None,
+ a.substitution.as_slice(interner),
+ b.substitution.as_slice(interner),
+ )
+ }
+}
+
+impl<I: Interner> Zip<I> for OpaqueTy<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ Zip::zip_with(zipper, variance, &a.opaque_ty_id, &b.opaque_ty_id)?;
+ zipper.zip_substs(
+ variance,
+ None,
+ a.substitution.as_slice(interner),
+ b.substitution.as_slice(interner),
+ )
+ }
+}
+
+impl<I: Interner> Zip<I> for DynTy<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ Zip::zip_with(
+ zipper,
+ variance.xform(Variance::Invariant),
+ &a.bounds,
+ &b.bounds,
+ )?;
+ Zip::zip_with(
+ zipper,
+ variance.xform(Variance::Contravariant),
+ &a.lifetime,
+ &b.lifetime,
+ )?;
+ Ok(())
+ }
+}
+
+impl<I: Interner> Zip<I> for FnSubst<I> {
+ fn zip_with<Z: Zipper<I>>(
+ zipper: &mut Z,
+ variance: Variance,
+ a: &Self,
+ b: &Self,
+ ) -> Fallible<()> {
+ let interner = zipper.interner();
+ // Parameters
+ Zip::zip_with(
+ zipper,
+ variance.xform(Variance::Contravariant),
+ &a.0.as_slice(interner)[..a.0.len(interner) - 1],
+ &b.0.as_slice(interner)[..b.0.len(interner) - 1],
+ )?;
+ // Return type
+ Zip::zip_with(
+ zipper,
+ variance,
+ a.0.iter(interner).last().unwrap(),
+ b.0.iter(interner).last().unwrap(),
+ )?;
+ Ok(())
+ }
+}