1 files changed, 586 insertions, 0 deletions

diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/traits/chalk.rs
new file mode 100644
index 000000000..b33653417
--- /dev/null
+++ b/crates/hir_ty/src/traits/chalk.rs
@@ -0,0 +1,586 @@
+//! Conversion code from/to Chalk.
+use std::sync::Arc;
+
+use log::debug;
+
+use chalk_ir::{fold::shift::Shift, CanonicalVarKinds, GenericArg, TypeName};
+use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
+
+use base_db::{salsa::InternKey, CrateId};
+use hir_def::{
+    lang_item::{lang_attr, LangItemTarget},
+    AssocContainerId, AssocItemId, HasModule, Lookup, TypeAliasId,
+};
+
+use super::ChalkContext;
+use crate::{
+    db::HirDatabase,
+    display::HirDisplay,
+    method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
+    utils::generics,
+    CallableDefId, DebruijnIndex, FnSig, GenericPredicate, Substs, Ty, TypeCtor,
+};
+use mapping::{
+    convert_where_clauses, generic_predicate_to_inline_bound, make_binders, TypeAliasAsValue,
+};
+
+pub use self::interner::*;
+
+pub(super) mod tls;
+mod interner;
+mod mapping;
+
+pub(super) trait ToChalk {
+    type Chalk;
+    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
+    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
+}
+
+pub(super) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
+where
+    T: ToChalk<Chalk = ChalkT>,
+{
+    T::from_chalk(db, chalk)
+}
+
+impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
+    fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
+        self.db.associated_ty_data(id)
+    }
+    fn trait_datum(&self, trait_id: TraitId) -> Arc<TraitDatum> {
+        self.db.trait_datum(self.krate, trait_id)
+    }
+    fn adt_datum(&self, struct_id: AdtId) -> Arc<StructDatum> {
+        self.db.struct_datum(self.krate, struct_id)
+    }
+    fn adt_repr(&self, _struct_id: AdtId) -> rust_ir::AdtRepr {
+        rust_ir::AdtRepr { repr_c: false, repr_packed: false }
+    }
+    fn impl_datum(&self, impl_id: ImplId) -> Arc<ImplDatum> {
+        self.db.impl_datum(self.krate, impl_id)
+    }
+
+    fn fn_def_datum(
+        &self,
+        fn_def_id: chalk_ir::FnDefId<Interner>,
+    ) -> Arc<rust_ir::FnDefDatum<Interner>> {
+        self.db.fn_def_datum(self.krate, fn_def_id)
+    }
+
+    fn impls_for_trait(
+        &self,
+        trait_id: TraitId,
+        parameters: &[GenericArg<Interner>],
+        binders: &CanonicalVarKinds<Interner>,
+    ) -> Vec<ImplId> {
+        debug!("impls_for_trait {:?}", trait_id);
+        let trait_: hir_def::TraitId = from_chalk(self.db, trait_id);
+
+        let ty: Ty = from_chalk(self.db, parameters[0].assert_ty_ref(&Interner).clone());
+
+        fn binder_kind(ty: &Ty, binders: &CanonicalVarKinds<Interner>) -> Option<chalk_ir::TyKind> {
+            if let Ty::Bound(bv) = ty {
+                let binders = binders.as_slice(&Interner);
+                if bv.debruijn == DebruijnIndex::INNERMOST {
+                    if let chalk_ir::VariableKind::Ty(tk) = binders[bv.index].kind {
+                        return Some(tk);
+                    }
+                }
+            }
+            None
+        }
+
+        let self_ty_fp = TyFingerprint::for_impl(&ty);
+        let fps: &[TyFingerprint] = match binder_kind(&ty, binders) {
+            Some(chalk_ir::TyKind::Integer) => &ALL_INT_FPS,
+            Some(chalk_ir::TyKind::Float) => &ALL_FLOAT_FPS,
+            _ => self_ty_fp.as_ref().map(std::slice::from_ref).unwrap_or(&[]),
+        };
+
+        // Note: Since we're using impls_for_trait, only impls where the trait
+        // can be resolved should ever reach Chalk. `impl_datum` relies on that
+        // and will panic if the trait can't be resolved.
+        let in_deps = self.db.trait_impls_in_deps(self.krate);
+        let in_self = self.db.trait_impls_in_crate(self.krate);
+        let impl_maps = [in_deps, in_self];
+
+        let id_to_chalk = |id: hir_def::ImplId| id.to_chalk(self.db);
+
+        let result: Vec<_> = if fps.is_empty() {
+            debug!("Unrestricted search for {:?} impls...", trait_);
+            impl_maps
+                .iter()
+                .flat_map(|crate_impl_defs| crate_impl_defs.for_trait(trait_).map(id_to_chalk))
+                .collect()
+        } else {
+            impl_maps
+                .iter()
+                .flat_map(|crate_impl_defs| {
+                    fps.iter().flat_map(move |fp| {
+                        crate_impl_defs.for_trait_and_self_ty(trait_, *fp).map(id_to_chalk)
+                    })
+                })
+                .collect()
+        };
+
+        debug!("impls_for_trait returned {} impls", result.len());
+        result
+    }
+    fn impl_provided_for(&self, auto_trait_id: TraitId, struct_id: AdtId) -> bool {
+        debug!("impl_provided_for {:?}, {:?}", auto_trait_id, struct_id);
+        false // FIXME
+    }
+    fn associated_ty_value(&self, id: AssociatedTyValueId) -> Arc<AssociatedTyValue> {
+        self.db.associated_ty_value(self.krate, id)
+    }
+
+    fn custom_clauses(&self) -> Vec<chalk_ir::ProgramClause<Interner>> {
+        vec![]
+    }
+    fn local_impls_to_coherence_check(&self, _trait_id: TraitId) -> Vec<ImplId> {
+        // We don't do coherence checking (yet)
+        unimplemented!()
+    }
+    fn interner(&self) -> &Interner {
+        &Interner
+    }
+    fn well_known_trait_id(
+        &self,
+        well_known_trait: rust_ir::WellKnownTrait,
+    ) -> Option<chalk_ir::TraitId<Interner>> {
+        let lang_attr = lang_attr_from_well_known_trait(well_known_trait);
+        let trait_ = match self.db.lang_item(self.krate, lang_attr.into()) {
+            Some(LangItemTarget::TraitId(trait_)) => trait_,
+            _ => return None,
+        };
+        Some(trait_.to_chalk(self.db))
+    }
+
+    fn program_clauses_for_env(
+        &self,
+        environment: &chalk_ir::Environment<Interner>,
+    ) -> chalk_ir::ProgramClauses<Interner> {
+        self.db.program_clauses_for_chalk_env(self.krate, environment.clone())
+    }
+
+    fn opaque_ty_data(&self, id: chalk_ir::OpaqueTyId<Interner>) -> Arc<OpaqueTyDatum> {
+        let interned_id = crate::db::InternedOpaqueTyId::from(id);
+        let full_id = self.db.lookup_intern_impl_trait_id(interned_id);
+        let (func, idx) = match full_id {
+            crate::OpaqueTyId::ReturnTypeImplTrait(func, idx) => (func, idx),
+        };
+        let datas =
+            self.db.return_type_impl_traits(func).expect("impl trait id without impl traits");
+        let data = &datas.value.impl_traits[idx as usize];
+        let bound = OpaqueTyDatumBound {
+            bounds: make_binders(
+                data.bounds
+                    .value
+                    .iter()
+                    .cloned()
+                    .filter(|b| !b.is_error())
+                    .map(|b| b.to_chalk(self.db))
+                    .collect(),
+                1,
+            ),
+            where_clauses: make_binders(vec![], 0),
+        };
+        let num_vars = datas.num_binders;
+        Arc::new(OpaqueTyDatum { opaque_ty_id: id, bound: make_binders(bound, num_vars) })
+    }
+
+    fn hidden_opaque_type(&self, _id: chalk_ir::OpaqueTyId<Interner>) -> chalk_ir::Ty<Interner> {
+        // FIXME: actually provide the hidden type; it is relevant for auto traits
+        Ty::Unknown.to_chalk(self.db)
+    }
+
+    fn is_object_safe(&self, _trait_id: chalk_ir::TraitId<Interner>) -> bool {
+        // FIXME: implement actual object safety
+        true
+    }
+
+    fn closure_kind(
+        &self,
+        _closure_id: chalk_ir::ClosureId<Interner>,
+        _substs: &chalk_ir::Substitution<Interner>,
+    ) -> rust_ir::ClosureKind {
+        // Fn is the closure kind that implements all three traits
+        rust_ir::ClosureKind::Fn
+    }
+    fn closure_inputs_and_output(
+        &self,
+        _closure_id: chalk_ir::ClosureId<Interner>,
+        substs: &chalk_ir::Substitution<Interner>,
+    ) -> chalk_ir::Binders<rust_ir::FnDefInputsAndOutputDatum<Interner>> {
+        let sig_ty: Ty =
+            from_chalk(self.db, substs.at(&Interner, 0).assert_ty_ref(&Interner).clone());
+        let sig = FnSig::from_fn_ptr_substs(
+            &sig_ty.substs().expect("first closure param should be fn ptr"),
+            false,
+        );
+        let io = rust_ir::FnDefInputsAndOutputDatum {
+            argument_types: sig.params().iter().map(|ty| ty.clone().to_chalk(self.db)).collect(),
+            return_type: sig.ret().clone().to_chalk(self.db),
+        };
+        make_binders(io.shifted_in(&Interner), 0)
+    }
+    fn closure_upvars(
+        &self,
+        _closure_id: chalk_ir::ClosureId<Interner>,
+        _substs: &chalk_ir::Substitution<Interner>,
+    ) -> chalk_ir::Binders<chalk_ir::Ty<Interner>> {
+        let ty = Ty::unit().to_chalk(self.db);
+        make_binders(ty, 0)
+    }
+    fn closure_fn_substitution(
+        &self,
+        _closure_id: chalk_ir::ClosureId<Interner>,
+        _substs: &chalk_ir::Substitution<Interner>,
+    ) -> chalk_ir::Substitution<Interner> {
+        Substs::empty().to_chalk(self.db)
+    }
+
+    fn trait_name(&self, _trait_id: chalk_ir::TraitId<Interner>) -> String {
+        unimplemented!()
+    }
+    fn adt_name(&self, _struct_id: chalk_ir::AdtId<Interner>) -> String {
+        unimplemented!()
+    }
+    fn assoc_type_name(&self, _assoc_ty_id: chalk_ir::AssocTypeId<Interner>) -> String {
+        unimplemented!()
+    }
+    fn opaque_type_name(&self, _opaque_ty_id: chalk_ir::OpaqueTyId<Interner>) -> String {
+        unimplemented!()
+    }
+    fn fn_def_name(&self, _fn_def_id: chalk_ir::FnDefId<Interner>) -> String {
+        unimplemented!()
+    }
+}
+
+pub(crate) fn program_clauses_for_chalk_env_query(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    environment: chalk_ir::Environment<Interner>,
+) -> chalk_ir::ProgramClauses<Interner> {
+    chalk_solve::program_clauses_for_env(&ChalkContext { db, krate }, &environment)
+}
+
+pub(crate) fn associated_ty_data_query(
+    db: &dyn HirDatabase,
+    id: AssocTypeId,
+) -> Arc<AssociatedTyDatum> {
+    debug!("associated_ty_data {:?}", id);
+    let type_alias: TypeAliasId = from_chalk(db, id);
+    let trait_ = match type_alias.lookup(db.upcast()).container {
+        AssocContainerId::TraitId(t) => t,
+        _ => panic!("associated type not in trait"),
+    };
+
+    // Lower bounds -- we could/should maybe move this to a separate query in `lower`
+    let type_alias_data = db.type_alias_data(type_alias);
+    let generic_params = generics(db.upcast(), type_alias.into());
+    let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let resolver = hir_def::resolver::HasResolver::resolver(type_alias, db.upcast());
+    let ctx = crate::TyLoweringContext::new(db, &resolver)
+        .with_type_param_mode(crate::lower::TypeParamLoweringMode::Variable);
+    let self_ty = Ty::Bound(crate::BoundVar::new(crate::DebruijnIndex::INNERMOST, 0));
+    let bounds = type_alias_data
+        .bounds
+        .iter()
+        .flat_map(|bound| GenericPredicate::from_type_bound(&ctx, bound, self_ty.clone()))
+        .filter_map(|pred| generic_predicate_to_inline_bound(db, &pred, &self_ty))
+        .map(|bound| make_binders(bound.shifted_in(&Interner), 0))
+        .collect();
+
+    let where_clauses = convert_where_clauses(db, type_alias.into(), &bound_vars);
+    let bound_data = rust_ir::AssociatedTyDatumBound { bounds, where_clauses };
+    let datum = AssociatedTyDatum {
+        trait_id: trait_.to_chalk(db),
+        id,
+        name: type_alias,
+        binders: make_binders(bound_data, generic_params.len()),
+    };
+    Arc::new(datum)
+}
+
+pub(crate) fn trait_datum_query(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    trait_id: TraitId,
+) -> Arc<TraitDatum> {
+    debug!("trait_datum {:?}", trait_id);
+    let trait_: hir_def::TraitId = from_chalk(db, trait_id);
+    let trait_data = db.trait_data(trait_);
+    debug!("trait {:?} = {:?}", trait_id, trait_data.name);
+    let generic_params = generics(db.upcast(), trait_.into());
+    let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let flags = rust_ir::TraitFlags {
+        auto: trait_data.auto,
+        upstream: trait_.lookup(db.upcast()).container.module(db.upcast()).krate != krate,
+        non_enumerable: true,
+        coinductive: false, // only relevant for Chalk testing
+        // FIXME: set these flags correctly
+        marker: false,
+        fundamental: false,
+    };
+    let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
+    let associated_ty_ids =
+        trait_data.associated_types().map(|type_alias| type_alias.to_chalk(db)).collect();
+    let trait_datum_bound = rust_ir::TraitDatumBound { where_clauses };
+    let well_known =
+        lang_attr(db.upcast(), trait_).and_then(|name| well_known_trait_from_lang_attr(&name));
+    let trait_datum = TraitDatum {
+        id: trait_id,
+        binders: make_binders(trait_datum_bound, bound_vars.len()),
+        flags,
+        associated_ty_ids,
+        well_known,
+    };
+    Arc::new(trait_datum)
+}
+
+fn well_known_trait_from_lang_attr(name: &str) -> Option<WellKnownTrait> {
+    Some(match name {
+        "sized" => WellKnownTrait::Sized,
+        "copy" => WellKnownTrait::Copy,
+        "clone" => WellKnownTrait::Clone,
+        "drop" => WellKnownTrait::Drop,
+        "fn_once" => WellKnownTrait::FnOnce,
+        "fn_mut" => WellKnownTrait::FnMut,
+        "fn" => WellKnownTrait::Fn,
+        "unsize" => WellKnownTrait::Unsize,
+        _ => return None,
+    })
+}
+
+fn lang_attr_from_well_known_trait(attr: WellKnownTrait) -> &'static str {
+    match attr {
+        WellKnownTrait::Sized => "sized",
+        WellKnownTrait::Copy => "copy",
+        WellKnownTrait::Clone => "clone",
+        WellKnownTrait::Drop => "drop",
+        WellKnownTrait::FnOnce => "fn_once",
+        WellKnownTrait::FnMut => "fn_mut",
+        WellKnownTrait::Fn => "fn",
+        WellKnownTrait::Unsize => "unsize",
+    }
+}
+
+pub(crate) fn struct_datum_query(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    struct_id: AdtId,
+) -> Arc<StructDatum> {
+    debug!("struct_datum {:?}", struct_id);
+    let type_ctor: TypeCtor = from_chalk(db, TypeName::Adt(struct_id));
+    debug!("struct {:?} = {:?}", struct_id, type_ctor);
+    let num_params = type_ctor.num_ty_params(db);
+    let upstream = type_ctor.krate(db) != Some(krate);
+    let where_clauses = type_ctor
+        .as_generic_def()
+        .map(|generic_def| {
+            let generic_params = generics(db.upcast(), generic_def);
+            let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+            convert_where_clauses(db, generic_def, &bound_vars)
+        })
+        .unwrap_or_else(Vec::new);
+    let flags = rust_ir::AdtFlags {
+        upstream,
+        // FIXME set fundamental and phantom_data flags correctly
+        fundamental: false,
+        phantom_data: false,
+    };
+    // FIXME provide enum variants properly (for auto traits)
+    let variant = rust_ir::AdtVariantDatum {
+        fields: Vec::new(), // FIXME add fields (only relevant for auto traits),
+    };
+    let struct_datum_bound = rust_ir::AdtDatumBound { variants: vec![variant], where_clauses };
+    let struct_datum = StructDatum {
+        // FIXME set ADT kind
+        kind: rust_ir::AdtKind::Struct,
+        id: struct_id,
+        binders: make_binders(struct_datum_bound, num_params),
+        flags,
+    };
+    Arc::new(struct_datum)
+}
+
+pub(crate) fn impl_datum_query(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    impl_id: ImplId,
+) -> Arc<ImplDatum> {
+    let _p = profile::span("impl_datum");
+    debug!("impl_datum {:?}", impl_id);
+    let impl_: hir_def::ImplId = from_chalk(db, impl_id);
+    impl_def_datum(db, krate, impl_id, impl_)
+}
+
+fn impl_def_datum(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    chalk_id: ImplId,
+    impl_id: hir_def::ImplId,
+) -> Arc<ImplDatum> {
+    let trait_ref = db
+        .impl_trait(impl_id)
+        // ImplIds for impls where the trait ref can't be resolved should never reach Chalk
+        .expect("invalid impl passed to Chalk")
+        .value;
+    let impl_data = db.impl_data(impl_id);
+
+    let generic_params = generics(db.upcast(), impl_id.into());
+    let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let trait_ = trait_ref.trait_;
+    let impl_type = if impl_id.lookup(db.upcast()).container.module(db.upcast()).krate == krate {
+        rust_ir::ImplType::Local
+    } else {
+        rust_ir::ImplType::External
+    };
+    let where_clauses = convert_where_clauses(db, impl_id.into(), &bound_vars);
+    let negative = impl_data.is_negative;
+    debug!(
+        "impl {:?}: {}{} where {:?}",
+        chalk_id,
+        if negative { "!" } else { "" },
+        trait_ref.display(db),
+        where_clauses
+    );
+    let trait_ref = trait_ref.to_chalk(db);
+
+    let polarity = if negative { rust_ir::Polarity::Negative } else { rust_ir::Polarity::Positive };
+
+    let impl_datum_bound = rust_ir::ImplDatumBound { trait_ref, where_clauses };
+    let trait_data = db.trait_data(trait_);
+    let associated_ty_value_ids = impl_data
+        .items
+        .iter()
+        .filter_map(|item| match item {
+            AssocItemId::TypeAliasId(type_alias) => Some(*type_alias),
+            _ => None,
+        })
+        .filter(|&type_alias| {
+            // don't include associated types that don't exist in the trait
+            let name = &db.type_alias_data(type_alias).name;
+            trait_data.associated_type_by_name(name).is_some()
+        })
+        .map(|type_alias| TypeAliasAsValue(type_alias).to_chalk(db))
+        .collect();
+    debug!("impl_datum: {:?}", impl_datum_bound);
+    let impl_datum = ImplDatum {
+        binders: make_binders(impl_datum_bound, bound_vars.len()),
+        impl_type,
+        polarity,
+        associated_ty_value_ids,
+    };
+    Arc::new(impl_datum)
+}
+
+pub(crate) fn associated_ty_value_query(
+    db: &dyn HirDatabase,
+    krate: CrateId,
+    id: AssociatedTyValueId,
+) -> Arc<AssociatedTyValue> {
+    let type_alias: TypeAliasAsValue = from_chalk(db, id);
+    type_alias_associated_ty_value(db, krate, type_alias.0)
+}
+
+fn type_alias_associated_ty_value(
+    db: &dyn HirDatabase,
+    _krate: CrateId,
+    type_alias: TypeAliasId,
+) -> Arc<AssociatedTyValue> {
+    let type_alias_data = db.type_alias_data(type_alias);
+    let impl_id = match type_alias.lookup(db.upcast()).container {
+        AssocContainerId::ImplId(it) => it,
+        _ => panic!("assoc ty value should be in impl"),
+    };
+
+    let trait_ref = db.impl_trait(impl_id).expect("assoc ty value should not exist").value; // we don't return any assoc ty values if the impl'd trait can't be resolved
+
+    let assoc_ty = db
+        .trait_data(trait_ref.trait_)
+        .associated_type_by_name(&type_alias_data.name)
+        .expect("assoc ty value should not exist"); // validated when building the impl data as well
+    let ty = db.ty(type_alias.into());
+    let value_bound = rust_ir::AssociatedTyValueBound { ty: ty.value.to_chalk(db) };
+    let value = rust_ir::AssociatedTyValue {
+        impl_id: impl_id.to_chalk(db),
+        associated_ty_id: assoc_ty.to_chalk(db),
+        value: make_binders(value_bound, ty.num_binders),
+    };
+    Arc::new(value)
+}
+
+pub(crate) fn fn_def_datum_query(
+    db: &dyn HirDatabase,
+    _krate: CrateId,
+    fn_def_id: FnDefId,
+) -> Arc<FnDefDatum> {
+    let callable_def: CallableDefId = from_chalk(db, fn_def_id);
+    let generic_params = generics(db.upcast(), callable_def.into());
+    let sig = db.callable_item_signature(callable_def);
+    let bound_vars = Substs::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let where_clauses = convert_where_clauses(db, callable_def.into(), &bound_vars);
+    let bound = rust_ir::FnDefDatumBound {
+        // Note: Chalk doesn't actually use this information yet as far as I am aware, but we provide it anyway
+        inputs_and_output: make_binders(
+            rust_ir::FnDefInputsAndOutputDatum {
+                argument_types: sig
+                    .value
+                    .params()
+                    .iter()
+                    .map(|ty| ty.clone().to_chalk(db))
+                    .collect(),
+                return_type: sig.value.ret().clone().to_chalk(db),
+            }
+            .shifted_in(&Interner),
+            0,
+        ),
+        where_clauses,
+    };
+    let datum = FnDefDatum {
+        id: fn_def_id,
+        abi: (),
+        safety: chalk_ir::Safety::Safe,
+        variadic: sig.value.is_varargs,
+        binders: make_binders(bound, sig.num_binders),
+    };
+    Arc::new(datum)
+}
+
+impl From<FnDefId> for crate::db::InternedCallableDefId {
+    fn from(fn_def_id: FnDefId) -> Self {
+        InternKey::from_intern_id(fn_def_id.0)
+    }
+}
+
+impl From<crate::db::InternedCallableDefId> for FnDefId {
+    fn from(callable_def_id: crate::db::InternedCallableDefId) -> Self {
+        chalk_ir::FnDefId(callable_def_id.as_intern_id())
+    }
+}
+
+impl From<OpaqueTyId> for crate::db::InternedOpaqueTyId {
+    fn from(id: OpaqueTyId) -> Self {
+        InternKey::from_intern_id(id.0)
+    }
+}
+
+impl From<crate::db::InternedOpaqueTyId> for OpaqueTyId {
+    fn from(id: crate::db::InternedOpaqueTyId) -> Self {
+        chalk_ir::OpaqueTyId(id.as_intern_id())
+    }
+}
+
+impl From<chalk_ir::ClosureId<Interner>> for crate::db::ClosureId {
+    fn from(id: chalk_ir::ClosureId<Interner>) -> Self {
+        Self::from_intern_id(id.0)
+    }
+}
+
+impl From<crate::db::ClosureId> for chalk_ir::ClosureId<Interner> {
+    fn from(id: crate::db::ClosureId) -> Self {
+        chalk_ir::ClosureId(id.as_intern_id())
+    }
+}