Use Chalk closure support

3 files changed, 68 insertions, 294 deletions

diff --git a/crates/ra_hir_ty/src/traits/builtin.rs b/crates/ra_hir_ty/src/traits/builtin.rs
deleted file mode 100644
index 60cc9a9f5..000000000
--- a/crates/ra_hir_ty/src/traits/builtin.rs
+++ /dev/null
@@ -1,178 +0,0 @@
-//! This module provides the built-in trait implementations, e.g. to make
-//! closures implement `Fn`.
-use hir_def::{expr::Expr, TraitId, TypeAliasId};
-use hir_expand::name::name;
-use ra_db::CrateId;
-
-use super::{AssocTyValue, Impl};
-use crate::{
-    db::HirDatabase, ApplicationTy, BoundVar, DebruijnIndex, Substs, TraitRef, Ty, TypeCtor,
-};
-
-pub(super) struct BuiltinImplData {
-    pub num_vars: usize,
-    pub trait_ref: TraitRef,
-    pub where_clauses: Vec<super::GenericPredicate>,
-    pub assoc_ty_values: Vec<AssocTyValue>,
-}
-
-pub(super) struct BuiltinImplAssocTyValueData {
-    pub impl_: Impl,
-    pub assoc_ty_id: TypeAliasId,
-    pub num_vars: usize,
-    pub value: Ty,
-}
-
-pub(super) fn get_builtin_impls(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    ty: &Ty,
-    // The first argument for the trait, if present
-    _arg: &Option<Ty>,
-    trait_: TraitId,
-    mut callback: impl FnMut(Impl),
-) {
-    // Note: since impl_datum needs to be infallible, we need to make sure here
-    // that we have all prerequisites to build the respective impls.
-    if let Ty::Apply(ApplicationTy { ctor: TypeCtor::Closure { def, expr }, .. }) = ty {
-        for &fn_trait in [super::FnTrait::FnOnce, super::FnTrait::FnMut, super::FnTrait::Fn].iter()
-        {
-            if let Some(actual_trait) = fn_trait.get_id(db, krate) {
-                if trait_ == actual_trait {
-                    let impl_ = super::ClosureFnTraitImplData { def: *def, expr: *expr, fn_trait };
-                    if check_closure_fn_trait_impl_prerequisites(db, krate, impl_) {
-                        callback(Impl::ClosureFnTraitImpl(impl_));
-                    }
-                }
-            }
-        }
-    }
-}
-
-pub(super) fn impl_datum(db: &dyn HirDatabase, krate: CrateId, impl_: Impl) -> BuiltinImplData {
-    match impl_ {
-        Impl::ImplDef(_) => unreachable!(),
-        Impl::ClosureFnTraitImpl(data) => closure_fn_trait_impl_datum(db, krate, data),
-    }
-}
-
-pub(super) fn associated_ty_value(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    data: AssocTyValue,
-) -> BuiltinImplAssocTyValueData {
-    match data {
-        AssocTyValue::TypeAlias(_) => unreachable!(),
-        AssocTyValue::ClosureFnTraitImplOutput(data) => {
-            closure_fn_trait_output_assoc_ty_value(db, krate, data)
-        }
-    }
-}
-
-// Closure Fn trait impls
-
-fn check_closure_fn_trait_impl_prerequisites(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    data: super::ClosureFnTraitImplData,
-) -> bool {
-    // the respective Fn/FnOnce/FnMut trait needs to exist
-    if data.fn_trait.get_id(db, krate).is_none() {
-        return false;
-    }
-
-    // FIXME: there are more assumptions that we should probably check here:
-    // the traits having no type params, FnOnce being a supertrait
-
-    // the FnOnce trait needs to exist and have an assoc type named Output
-    let fn_once_trait = match (super::FnTrait::FnOnce).get_id(db, krate) {
-        Some(t) => t,
-        None => return false,
-    };
-    db.trait_data(fn_once_trait).associated_type_by_name(&name![Output]).is_some()
-}
-
-fn closure_fn_trait_impl_datum(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    data: super::ClosureFnTraitImplData,
-) -> BuiltinImplData {
-    // for some closure |X, Y| -> Z:
-    // impl<T, U, V> Fn<(T, U)> for closure<fn(T, U) -> V> { Output = V }
-
-    let trait_ = data
-        .fn_trait
-        .get_id(db, krate) // get corresponding fn trait
-        // the existence of the Fn trait has been checked before
-        .expect("fn trait for closure impl missing");
-
-    let num_args: u16 = match &db.body(data.def)[data.expr] {
-        Expr::Lambda { args, .. } => args.len() as u16,
-        _ => {
-            log::warn!("closure for closure type {:?} not found", data);
-            0
-        }
-    };
-
-    let arg_ty = Ty::apply(
-        TypeCtor::Tuple { cardinality: num_args },
-        Substs::builder(num_args as usize)
-            .fill_with_bound_vars(DebruijnIndex::INNERMOST, 0)
-            .build(),
-    );
-    let sig_ty = Ty::apply(
-        TypeCtor::FnPtr { num_args, is_varargs: false },
-        Substs::builder(num_args as usize + 1)
-            .fill_with_bound_vars(DebruijnIndex::INNERMOST, 0)
-            .build(),
-    );
-
-    let self_ty = Ty::apply_one(TypeCtor::Closure { def: data.def, expr: data.expr }, sig_ty);
-
-    let trait_ref = TraitRef {
-        trait_,
-        substs: Substs::build_for_def(db, trait_).push(self_ty).push(arg_ty).build(),
-    };
-
-    let output_ty_id = AssocTyValue::ClosureFnTraitImplOutput(data);
-
-    BuiltinImplData {
-        num_vars: num_args as usize + 1,
-        trait_ref,
-        where_clauses: Vec::new(),
-        assoc_ty_values: vec![output_ty_id],
-    }
-}
-
-fn closure_fn_trait_output_assoc_ty_value(
-    db: &dyn HirDatabase,
-    krate: CrateId,
-    data: super::ClosureFnTraitImplData,
-) -> BuiltinImplAssocTyValueData {
-    let impl_ = Impl::ClosureFnTraitImpl(data);
-
-    let num_args: u16 = match &db.body(data.def)[data.expr] {
-        Expr::Lambda { args, .. } => args.len() as u16,
-        _ => {
-            log::warn!("closure for closure type {:?} not found", data);
-            0
-        }
-    };
-
-    let output_ty = Ty::Bound(BoundVar::new(DebruijnIndex::INNERMOST, num_args.into()));
-
-    let fn_once_trait =
-        (super::FnTrait::FnOnce).get_id(db, krate).expect("assoc ty value should not exist");
-
-    let output_ty_id = db
-        .trait_data(fn_once_trait)
-        .associated_type_by_name(&name![Output])
-        .expect("assoc ty value should not exist");
-
-    BuiltinImplAssocTyValueData {
-        impl_,
-        assoc_ty_id: output_ty_id,
-        num_vars: num_args as usize + 1,
-        value: output_ty,
-    }
-}
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index c448aea65..7f8ba2f12 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -12,15 +12,17 @@ use hir_def::{
 };
 use ra_db::{salsa::InternKey, CrateId};
 
-use super::{builtin, AssocTyValue, ChalkContext, Impl};
+use super::ChalkContext;
 use crate::{
     db::HirDatabase,
     display::HirDisplay,
     method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
     utils::generics,
-    CallableDef, DebruijnIndex, GenericPredicate, Substs, Ty, TypeCtor,
+    CallableDef, DebruijnIndex, FnSig, GenericPredicate, Substs, Ty, TypeCtor,
+};
+use mapping::{
+    convert_where_clauses, generic_predicate_to_inline_bound, make_binders, TypeAliasAsValue,
 };
-use mapping::{convert_where_clauses, generic_predicate_to_inline_bound, make_binders};
 
 pub use self::interner::*;
 
@@ -102,9 +104,9 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         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| Impl::ImplDef(id).to_chalk(self.db);
+        let id_to_chalk = |id: hir_def::ImplId| id.to_chalk(self.db);
 
-        let mut result: Vec<_> = if fps.is_empty() {
+        let result: Vec<_> = if fps.is_empty() {
             debug!("Unrestricted search for {:?} impls...", trait_);
             impl_maps
                 .iter()
@@ -121,13 +123,6 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
                 .collect()
         };
 
-        let arg: Option<Ty> =
-            parameters.get(1).map(|p| from_chalk(self.db, p.assert_ty_ref(&Interner).clone()));
-
-        builtin::get_builtin_impls(self.db, self.krate, &ty, &arg, trait_, |i| {
-            result.push(i.to_chalk(self.db))
-        });
-
         debug!("impls_for_trait returned {} impls", result.len());
         result
     }
@@ -217,32 +212,40 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         _closure_id: chalk_ir::ClosureId<Interner>,
         _substs: &chalk_ir::Substitution<Interner>,
     ) -> rust_ir::ClosureKind {
-        // FIXME: implement closure support
-        unimplemented!()
+        // 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>,
+        substs: &chalk_ir::Substitution<Interner>,
     ) -> chalk_ir::Binders<rust_ir::FnDefInputsAndOutputDatum<Interner>> {
-        // FIXME: implement closure support
-        unimplemented!()
+        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>> {
-        // FIXME: implement closure support
-        unimplemented!()
+        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> {
-        // FIXME: implement closure support
-        unimplemented!()
+        Substs::empty().to_chalk(self.db)
     }
 
     fn trait_name(&self, _trait_id: chalk_ir::TraitId<Interner>) -> String {
@@ -417,11 +420,8 @@ pub(crate) fn impl_datum_query(
 ) -> Arc<ImplDatum> {
     let _p = ra_prof::profile("impl_datum");
     debug!("impl_datum {:?}", impl_id);
-    let impl_: Impl = from_chalk(db, impl_id);
-    match impl_ {
-        Impl::ImplDef(impl_def) => impl_def_datum(db, krate, impl_id, impl_def),
-        _ => Arc::new(builtin::impl_datum(db, krate, impl_).to_chalk(db)),
-    }
+    let impl_: hir_def::ImplId = from_chalk(db, impl_id);
+    impl_def_datum(db, krate, impl_id, impl_)
 }
 
 fn impl_def_datum(
@@ -472,7 +472,7 @@ fn impl_def_datum(
             let name = &db.type_alias_data(type_alias).name;
             trait_data.associated_type_by_name(name).is_some()
         })
-        .map(|type_alias| AssocTyValue::TypeAlias(type_alias).to_chalk(db))
+        .map(|type_alias| TypeAliasAsValue(type_alias).to_chalk(db))
         .collect();
     debug!("impl_datum: {:?}", impl_datum_bound);
     let impl_datum = ImplDatum {
@@ -489,13 +489,8 @@ pub(crate) fn associated_ty_value_query(
     krate: CrateId,
     id: AssociatedTyValueId,
 ) -> Arc<AssociatedTyValue> {
-    let data: AssocTyValue = from_chalk(db, id);
-    match data {
-        AssocTyValue::TypeAlias(type_alias) => {
-            type_alias_associated_ty_value(db, krate, type_alias)
-        }
-        _ => Arc::new(builtin::associated_ty_value(db, krate, data).to_chalk(db)),
-    }
+    let type_alias: TypeAliasAsValue = from_chalk(db, id);
+    type_alias_associated_ty_value(db, krate, type_alias.0)
 }
 
 fn type_alias_associated_ty_value(
@@ -518,7 +513,7 @@ fn type_alias_associated_ty_value(
     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::ImplDef(impl_id).to_chalk(db),
+        impl_id: impl_id.to_chalk(db),
         associated_ty_id: assoc_ty.to_chalk(db),
         value: make_binders(value_bound, ty.num_binders),
     };
@@ -581,18 +576,6 @@ impl From<crate::CallableDefId> for FnDefId {
     }
 }
 
-impl From<ImplId> for crate::traits::GlobalImplId {
-    fn from(impl_id: ImplId) -> Self {
-        InternKey::from_intern_id(impl_id.0)
-    }
-}
-
-impl From<crate::traits::GlobalImplId> for ImplId {
-    fn from(impl_id: crate::traits::GlobalImplId) -> Self {
-        chalk_ir::ImplId(impl_id.as_intern_id())
-    }
-}
-
 impl From<OpaqueTyId> for crate::db::InternedOpaqueTyId {
     fn from(id: OpaqueTyId) -> Self {
         InternKey::from_intern_id(id.0)
@@ -605,14 +588,14 @@ impl From<crate::db::InternedOpaqueTyId> for OpaqueTyId {
     }
 }
 
-impl From<rust_ir::AssociatedTyValueId<Interner>> for crate::traits::AssocTyValueId {
-    fn from(id: rust_ir::AssociatedTyValueId<Interner>) -> Self {
+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::traits::AssocTyValueId> for rust_ir::AssociatedTyValueId<Interner> {
-    fn from(assoc_ty_value_id: crate::traits::AssocTyValueId) -> Self {
-        rust_ir::AssociatedTyValueId(assoc_ty_value_id.as_intern_id())
+impl From<crate::db::ClosureId> for chalk_ir::ClosureId<Interner> {
+    fn from(id: crate::db::ClosureId) -> Self {
+        chalk_ir::ClosureId(id.as_intern_id())
     }
 }
diff --git a/crates/ra_hir_ty/src/traits/chalk/mapping.rs b/crates/ra_hir_ty/src/traits/chalk/mapping.rs
index 3ebb55f77..796947e69 100644
--- a/crates/ra_hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/ra_hir_ty/src/traits/chalk/mapping.rs
@@ -15,7 +15,7 @@ use ra_db::salsa::InternKey;
 use crate::{
     db::HirDatabase,
     primitive::{FloatBitness, FloatTy, IntBitness, IntTy, Signedness},
-    traits::{builtin, AssocTyValue, Canonical, Impl, Obligation},
+    traits::{Canonical, Obligation},
     ApplicationTy, CallableDef, GenericPredicate, InEnvironment, OpaqueTy, OpaqueTyId,
     ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TyKind, TypeCtor,
 };
@@ -311,8 +311,15 @@ impl ToChalk for TypeCtor {
             }
             TypeCtor::Never => TypeName::Never,
 
-            // FIXME convert these
-            TypeCtor::Adt(_) | TypeCtor::FnPtr { .. } | TypeCtor::Closure { .. } => {
+            TypeCtor::Closure { def, expr } => {
+                let closure_id = db.intern_closure((def, expr));
+                TypeName::Closure(closure_id.into())
+            }
+
+            TypeCtor::FnPtr { .. } => panic!("Trying to convert FnPtr to TypeName"),
+
+            TypeCtor::Adt(_) => {
+                // FIXME no interning needed anymore
                 // other TypeCtors get interned and turned into a chalk StructId
                 let struct_id = db.intern_type_ctor(self).into();
                 TypeName::Adt(struct_id)
@@ -355,13 +362,16 @@ impl ToChalk for TypeCtor {
                 let callable_def = from_chalk(db, fn_def_id);
                 TypeCtor::FnDef(callable_def)
             }
+            TypeName::Array => TypeCtor::Array,
 
-            TypeName::Array | TypeName::Error => {
-                // this should not be reached, since we don't represent TypeName::Error with TypeCtor
-                unreachable!()
+            TypeName::Closure(id) => {
+                let id: crate::db::ClosureId = id.into();
+                let (def, expr) = db.lookup_intern_closure(id);
+                TypeCtor::Closure { def, expr }
             }
-            TypeName::Closure(_) => {
-                // FIXME: implement closure support
+
+            TypeName::Error => {
+                // this should not be reached, since we don't represent TypeName::Error with TypeCtor
                 unreachable!()
             }
         }
@@ -433,15 +443,15 @@ impl ToChalk for Mutability {
     }
 }
 
-impl ToChalk for Impl {
+impl ToChalk for hir_def::ImplId {
     type Chalk = ImplId;
 
-    fn to_chalk(self, db: &dyn HirDatabase) -> ImplId {
-        db.intern_chalk_impl(self).into()
+    fn to_chalk(self, _db: &dyn HirDatabase) -> ImplId {
+        chalk_ir::ImplId(self.as_intern_id())
     }
 
-    fn from_chalk(db: &dyn HirDatabase, impl_id: ImplId) -> Impl {
-        db.lookup_intern_chalk_impl(impl_id.into())
+    fn from_chalk(_db: &dyn HirDatabase, impl_id: ImplId) -> hir_def::ImplId {
+        InternKey::from_intern_id(impl_id.0)
     }
 }
 
@@ -469,15 +479,20 @@ impl ToChalk for TypeAliasId {
     }
 }
 
-impl ToChalk for AssocTyValue {
+pub struct TypeAliasAsValue(pub TypeAliasId);
+
+impl ToChalk for TypeAliasAsValue {
     type Chalk = AssociatedTyValueId;
 
-    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValueId {
-        db.intern_assoc_ty_value(self).into()
+    fn to_chalk(self, _db: &dyn HirDatabase) -> AssociatedTyValueId {
+        rust_ir::AssociatedTyValueId(self.0.as_intern_id())
     }
 
-    fn from_chalk(db: &dyn HirDatabase, assoc_ty_value_id: AssociatedTyValueId) -> AssocTyValue {
-        db.lookup_intern_assoc_ty_value(assoc_ty_value_id.into())
+    fn from_chalk(
+        _db: &dyn HirDatabase,
+        assoc_ty_value_id: AssociatedTyValueId,
+    ) -> TypeAliasAsValue {
+        TypeAliasAsValue(TypeAliasId::from_intern_id(assoc_ty_value_id.0))
     }
 }
 
@@ -686,52 +701,6 @@ where
     }
 }
 
-impl ToChalk for builtin::BuiltinImplData {
-    type Chalk = ImplDatum;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> ImplDatum {
-        let impl_type = rust_ir::ImplType::External;
-        let where_clauses = self.where_clauses.into_iter().map(|w| w.to_chalk(db)).collect();
-
-        let impl_datum_bound =
-            rust_ir::ImplDatumBound { trait_ref: self.trait_ref.to_chalk(db), where_clauses };
-        let associated_ty_value_ids =
-            self.assoc_ty_values.into_iter().map(|v| v.to_chalk(db)).collect();
-        rust_ir::ImplDatum {
-            binders: make_binders(impl_datum_bound, self.num_vars),
-            impl_type,
-            polarity: rust_ir::Polarity::Positive,
-            associated_ty_value_ids,
-        }
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, _data: ImplDatum) -> Self {
-        unimplemented!()
-    }
-}
-
-impl ToChalk for builtin::BuiltinImplAssocTyValueData {
-    type Chalk = AssociatedTyValue;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> AssociatedTyValue {
-        let ty = self.value.to_chalk(db);
-        let value_bound = rust_ir::AssociatedTyValueBound { ty };
-
-        rust_ir::AssociatedTyValue {
-            associated_ty_id: self.assoc_ty_id.to_chalk(db),
-            impl_id: self.impl_.to_chalk(db),
-            value: make_binders(value_bound, self.num_vars),
-        }
-    }
-
-    fn from_chalk(
-        _db: &dyn HirDatabase,
-        _data: AssociatedTyValue,
-    ) -> builtin::BuiltinImplAssocTyValueData {
-        unimplemented!()
-    }
-}
-
 pub(super) fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T>
 where
     T: HasInterner<Interner = Interner>,