5 files changed, 111 insertions, 150 deletions

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index b023ae690..beb2efb7a 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -35,15 +35,15 @@ use test_utils::tested_by;
 
 use super::{
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
-    ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypableDef,
-    TypeCtor, TypeWalk, Uncertain,
+    ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypeCtor,
+    TypeWalk, Uncertain,
 };
 use crate::{
     code_model::TypeAlias,
     db::HirDatabase,
     expr::{BindingAnnotation, Body, ExprId, PatId},
     ty::infer::diagnostics::InferenceDiagnostic,
-    Adt, AssocItem, DefWithBody, FloatTy, Function, IntTy, Path, StructField, VariantDef,
+    AssocItem, DefWithBody, FloatTy, Function, IntTy, Path, StructField, VariantDef,
 };
 
 macro_rules! ty_app {
@@ -520,45 +520,22 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             None => return (Ty::Unknown, None),
         };
         let resolver = &self.resolver;
-        let def: TypableDef =
-            // FIXME: this should resolve assoc items as well, see this example:
-            // https://play.rust-lang.org/?gist=087992e9e22495446c01c0d4e2d69521
-            match resolver.resolve_path_in_type_ns_fully(self.db, &path) {
-                Some(TypeNs::AdtId(AdtId::StructId(it))) => it.into(),
-                Some(TypeNs::AdtId(AdtId::UnionId(it))) => it.into(),
-                Some(TypeNs::AdtSelfType(adt)) => adt.into(),
-                Some(TypeNs::EnumVariantId(it)) => it.into(),
-                Some(TypeNs::TypeAliasId(it)) => it.into(),
-
-                Some(TypeNs::SelfType(_)) |
-                Some(TypeNs::GenericParam(_)) |
-                Some(TypeNs::BuiltinType(_)) |
-                Some(TypeNs::TraitId(_)) |
-                Some(TypeNs::AdtId(AdtId::EnumId(_))) |
-                None => {
-                    return (Ty::Unknown, None)
-                }
-            };
-        // FIXME remove the duplication between here and `Ty::from_path`?
-        let substs = Ty::substs_from_path(self.db, resolver, path, def);
-        match def {
-            TypableDef::Adt(Adt::Struct(s)) => {
-                let ty = s.ty(self.db);
+        // FIXME: this should resolve assoc items as well, see this example:
+        // https://play.rust-lang.org/?gist=087992e9e22495446c01c0d4e2d69521
+        match resolver.resolve_path_in_type_ns_fully(self.db, &path) {
+            Some(TypeNs::AdtId(AdtId::StructId(strukt))) => {
+                let substs = Ty::substs_from_path(self.db, resolver, path, strukt.into());
+                let ty = self.db.ty(strukt.into());
                 let ty = self.insert_type_vars(ty.apply_substs(substs));
-                (ty, Some(s.into()))
+                (ty, Some(VariantDef::Struct(strukt.into())))
             }
-            TypableDef::EnumVariant(var) => {
-                let ty = var.parent_enum(self.db).ty(self.db);
+            Some(TypeNs::EnumVariantId(var)) => {
+                let substs = Ty::substs_from_path(self.db, resolver, path, var.into());
+                let ty = self.db.ty(var.parent.into());
                 let ty = self.insert_type_vars(ty.apply_substs(substs));
-                (ty, Some(var.into()))
+                (ty, Some(VariantDef::EnumVariant(var.into())))
             }
-            TypableDef::Adt(Adt::Enum(_))
-            | TypableDef::Adt(Adt::Union(_))
-            | TypableDef::TypeAlias(_)
-            | TypableDef::Function(_)
-            | TypableDef::Const(_)
-            | TypableDef::Static(_)
-            | TypableDef::BuiltinType(_) => (Ty::Unknown, None),
+            Some(_) | None => (Ty::Unknown, None),
         }
     }
 
diff --git a/crates/ra_hir/src/ty/infer/expr.rs b/crates/ra_hir/src/ty/infer/expr.rs
index 3d0895dc6..eb221d6bc 100644
--- a/crates/ra_hir/src/ty/infer/expr.rs
+++ b/crates/ra_hir/src/ty/infer/expr.rs
@@ -17,8 +17,8 @@ use crate::{
     expr::{Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp},
     ty::{
         autoderef, method_resolution, op, traits::InEnvironment, CallableDef, InferTy, IntTy,
-        Mutability, Namespace, Obligation, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty,
-        TypeCtor, TypeWalk, Uncertain,
+        Mutability, Obligation, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
+        TypeWalk, Uncertain,
     },
     Name,
 };
@@ -558,11 +558,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Some((ty, func)) => {
                 let ty = canonicalized_receiver.decanonicalize_ty(ty);
                 self.write_method_resolution(tgt_expr, func);
-                (
-                    ty,
-                    self.db.type_for_def(func.into(), Namespace::Values),
-                    Some(self.db.generic_params(func.id.into())),
-                )
+                (ty, self.db.value_ty(func.id.into()), Some(self.db.generic_params(func.id.into())))
             }
             None => (receiver_ty, Ty::Unknown, None),
         };
diff --git a/crates/ra_hir/src/ty/infer/path.rs b/crates/ra_hir/src/ty/infer/path.rs
index 202fff4f3..be2067dd4 100644
--- a/crates/ra_hir/src/ty/infer/path.rs
+++ b/crates/ra_hir/src/ty/infer/path.rs
@@ -7,7 +7,7 @@ use hir_def::{
 
 use crate::{
     db::HirDatabase,
-    ty::{method_resolution, Namespace, Substs, Ty, TypableDef, TypeWalk},
+    ty::{method_resolution, Substs, Ty, TypeWalk, ValueTyDefId},
     AssocItem, Container, Function, Name, Path,
 };
 
@@ -56,7 +56,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
         };
 
-        let typable: TypableDef = match value {
+        let typable: ValueTyDefId = match value {
             ValueNs::LocalBinding(pat) => {
                 let ty = self.result.type_of_pat.get(pat)?.clone();
                 let ty = self.resolve_ty_as_possible(&mut vec![], ty);
@@ -69,11 +69,10 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             ValueNs::EnumVariantId(it) => it.into(),
         };
 
-        let mut ty = self.db.type_for_def(typable, Namespace::Values);
+        let mut ty = self.db.value_ty(typable);
         if let Some(self_subst) = self_subst {
             ty = ty.subst(&self_subst);
         }
-
         let substs = Ty::substs_from_path(self.db, &self.resolver, path, typable);
         let ty = ty.subst(&substs);
         Some(ty)
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index c3c47a576..709492d21 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -14,8 +14,8 @@ use hir_def::{
     path::{GenericArg, PathSegment},
     resolver::{HasResolver, Resolver, TypeNs},
     type_ref::{TypeBound, TypeRef},
-    AdtId, AstItemDef, EnumVariantId, FunctionId, GenericDefId, HasModule, LocalStructFieldId,
-    Lookup, StructId, TraitId, VariantId,
+    AdtId, AstItemDef, ConstId, EnumId, EnumVariantId, FunctionId, GenericDefId, HasModule,
+    LocalStructFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId, UnionId, VariantId,
 };
 use ra_arena::map::ArenaMap;
 use ra_db::CrateId;
@@ -35,17 +35,6 @@ use crate::{
     TypeAlias, Union,
 };
 
-// FIXME: this is only really used in `type_for_def`, which contains a bunch of
-// impossible cases. Perhaps we should recombine `TypeableDef` and `Namespace`
-// into a `AsTypeDef`, `AsValueDef` enums?
-#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub enum Namespace {
-    Types,
-    Values,
-    // Note that only type inference uses this enum, and it doesn't care about macros.
-    // Macro,
-}
-
 impl Ty {
     pub(crate) fn from_hir(db: &impl HirDatabase, resolver: &Resolver, type_ref: &TypeRef) -> Self {
         match type_ref {
@@ -281,27 +270,15 @@ impl Ty {
         db: &impl HirDatabase,
         resolver: &Resolver,
         segment: &PathSegment,
-        typable: TypableDef,
+        typable: TyDefId,
     ) -> Ty {
-        let ty = db.type_for_def(typable, Namespace::Types);
-        let substs = Ty::substs_from_path_segment(db, resolver, segment, typable);
-        ty.subst(&substs)
-    }
-
-    pub(super) fn substs_from_path_segment(
-        db: &impl HirDatabase,
-        resolver: &Resolver,
-        segment: &PathSegment,
-        resolved: TypableDef,
-    ) -> Substs {
-        let def_generic: Option<GenericDefId> = match resolved {
-            TypableDef::Function(func) => Some(func.id.into()),
-            TypableDef::Adt(adt) => Some(adt.into()),
-            TypableDef::EnumVariant(var) => Some(var.parent_enum(db).id.into()),
-            TypableDef::TypeAlias(t) => Some(t.id.into()),
-            TypableDef::Const(_) | TypableDef::Static(_) | TypableDef::BuiltinType(_) => None,
+        let generic_def = match typable {
+            TyDefId::BuiltinType(_) => None,
+            TyDefId::AdtId(it) => Some(it.into()),
+            TyDefId::TypeAliasId(it) => Some(it.into()),
         };
-        substs_from_path_segment(db, resolver, segment, def_generic, false)
+        let substs = substs_from_path_segment(db, resolver, segment, generic_def, false);
+        db.ty(typable).subst(&substs)
     }
 
     /// Collect generic arguments from a path into a `Substs`. See also
@@ -310,17 +287,18 @@ impl Ty {
         db: &impl HirDatabase,
         resolver: &Resolver,
         path: &Path,
-        resolved: TypableDef,
+        // Note that we don't call `db.value_type(resolved)` here,
+        // `ValueTyDefId` is just a convenient way to pass generics and
+        // special-case enum variants
+        resolved: ValueTyDefId,
     ) -> Substs {
         let last = path.segments.last().expect("path should have at least one segment");
-        let segment = match resolved {
-            TypableDef::Function(_)
-            | TypableDef::Adt(_)
-            | TypableDef::Const(_)
-            | TypableDef::Static(_)
-            | TypableDef::TypeAlias(_)
-            | TypableDef::BuiltinType(_) => last,
-            TypableDef::EnumVariant(_) => {
+        let (segment, generic_def) = match resolved {
+            ValueTyDefId::FunctionId(it) => (last, Some(it.into())),
+            ValueTyDefId::StructId(it) => (last, Some(it.into())),
+            ValueTyDefId::ConstId(it) => (last, Some(it.into())),
+            ValueTyDefId::StaticId(_) => (last, None),
+            ValueTyDefId::EnumVariantId(var) => {
                 // the generic args for an enum variant may be either specified
                 // on the segment referring to the enum, or on the segment
                 // referring to the variant. So `Option::<T>::None` and
@@ -334,10 +312,10 @@ impl Ty {
                     // Option::None::<T>
                     last
                 };
-                segment
+                (segment, Some(var.parent.into()))
             }
         };
-        Ty::substs_from_path_segment(db, resolver, segment, resolved)
+        substs_from_path_segment(db, resolver, segment, generic_def, false)
     }
 }
 
@@ -522,33 +500,6 @@ fn assoc_type_bindings_from_type_bound<'a>(
         })
 }
 
-/// Build the declared type of an item. This depends on the namespace; e.g. for
-/// `struct Foo(usize)`, we have two types: The type of the struct itself, and
-/// the constructor function `(usize) -> Foo` which lives in the values
-/// namespace.
-pub(crate) fn type_for_def(db: &impl HirDatabase, def: TypableDef, ns: Namespace) -> Ty {
-    match (def, ns) {
-        (TypableDef::Function(f), Namespace::Values) => type_for_fn(db, f),
-        (TypableDef::Adt(Adt::Struct(s)), Namespace::Values) => type_for_struct_constructor(db, s),
-        (TypableDef::Adt(adt), Namespace::Types) => type_for_adt(db, adt),
-        (TypableDef::EnumVariant(v), Namespace::Values) => type_for_enum_variant_constructor(db, v),
-        (TypableDef::TypeAlias(t), Namespace::Types) => type_for_type_alias(db, t),
-        (TypableDef::Const(c), Namespace::Values) => type_for_const(db, c),
-        (TypableDef::Static(c), Namespace::Values) => type_for_static(db, c),
-        (TypableDef::BuiltinType(t), Namespace::Types) => type_for_builtin(t),
-
-        // 'error' cases:
-        (TypableDef::Function(_), Namespace::Types) => Ty::Unknown,
-        (TypableDef::Adt(Adt::Union(_)), Namespace::Values) => Ty::Unknown,
-        (TypableDef::Adt(Adt::Enum(_)), Namespace::Values) => Ty::Unknown,
-        (TypableDef::EnumVariant(_), Namespace::Types) => Ty::Unknown,
-        (TypableDef::TypeAlias(_), Namespace::Values) => Ty::Unknown,
-        (TypableDef::Const(_), Namespace::Types) => Ty::Unknown,
-        (TypableDef::Static(_), Namespace::Types) => Ty::Unknown,
-        (TypableDef::BuiltinType(_), Namespace::Values) => Ty::Unknown,
-    }
-}
-
 /// Build the signature of a callable item (function, struct or enum variant).
 pub(crate) fn callable_item_sig(db: &impl HirDatabase, def: CallableDef) -> FnSig {
     match def {
@@ -647,24 +598,24 @@ fn fn_sig_for_fn(db: &impl HirDatabase, def: FunctionId) -> FnSig {
 
 /// Build the declared type of a function. This should not need to look at the
 /// function body.
-fn type_for_fn(db: &impl HirDatabase, def: Function) -> Ty {
-    let generics = db.generic_params(def.id.into());
+fn type_for_fn(db: &impl HirDatabase, def: FunctionId) -> Ty {
+    let generics = db.generic_params(def.into());
     let substs = Substs::identity(&generics);
-    Ty::apply(TypeCtor::FnDef(def.id.into()), substs)
+    Ty::apply(TypeCtor::FnDef(def.into()), substs)
 }
 
 /// Build the declared type of a const.
-fn type_for_const(db: &impl HirDatabase, def: Const) -> Ty {
-    let data = db.const_data(def.id);
-    let resolver = def.id.resolver(db);
+fn type_for_const(db: &impl HirDatabase, def: ConstId) -> Ty {
+    let data = db.const_data(def);
+    let resolver = def.resolver(db);
 
     Ty::from_hir(db, &resolver, &data.type_ref)
 }
 
 /// Build the declared type of a static.
-fn type_for_static(db: &impl HirDatabase, def: Static) -> Ty {
-    let data = db.static_data(def.id);
-    let resolver = def.id.resolver(db);
+fn type_for_static(db: &impl HirDatabase, def: StaticId) -> Ty {
+    let data = db.static_data(def);
+    let resolver = def.resolver(db);
 
     Ty::from_hir(db, &resolver, &data.type_ref)
 }
@@ -688,19 +639,19 @@ fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> FnSig
         .iter()
         .map(|(_, field)| Ty::from_hir(db, &resolver, &field.type_ref))
         .collect::<Vec<_>>();
-    let ret = type_for_adt(db, Struct::from(def));
+    let ret = type_for_adt(db, def.into());
     FnSig::from_params_and_return(params, ret)
 }
 
 /// Build the type of a tuple struct constructor.
-fn type_for_struct_constructor(db: &impl HirDatabase, def: Struct) -> Ty {
-    let struct_data = db.struct_data(def.id.into());
+fn type_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> Ty {
+    let struct_data = db.struct_data(def.into());
     if struct_data.variant_data.is_unit() {
-        return type_for_adt(db, def); // Unit struct
+        return type_for_adt(db, def.into()); // Unit struct
     }
-    let generics = db.generic_params(def.id.into());
+    let generics = db.generic_params(def.into());
     let substs = Substs::identity(&generics);
-    Ty::apply(TypeCtor::FnDef(def.id.into()), substs)
+    Ty::apply(TypeCtor::FnDef(def.into()), substs)
 }
 
 fn fn_sig_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariantId) -> FnSig {
@@ -714,34 +665,33 @@ fn fn_sig_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariantId
         .collect::<Vec<_>>();
     let generics = db.generic_params(def.parent.into());
     let substs = Substs::identity(&generics);
-    let ret = type_for_adt(db, Enum::from(def.parent)).subst(&substs);
+    let ret = type_for_adt(db, def.parent.into()).subst(&substs);
     FnSig::from_params_and_return(params, ret)
 }
 
 /// Build the type of a tuple enum variant constructor.
-fn type_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariant) -> Ty {
-    let var_data = def.variant_data(db);
+fn type_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariantId) -> Ty {
+    let enum_data = db.enum_data(def.parent);
+    let var_data = &enum_data.variants[def.local_id].variant_data;
     if var_data.is_unit() {
-        return type_for_adt(db, def.parent_enum(db)); // Unit variant
+        return type_for_adt(db, def.parent.into()); // Unit variant
     }
-    let generics = db.generic_params(def.parent_enum(db).id.into());
+    let generics = db.generic_params(def.parent.into());
     let substs = Substs::identity(&generics);
     Ty::apply(TypeCtor::FnDef(EnumVariantId::from(def).into()), substs)
 }
 
-fn type_for_adt(db: &impl HirDatabase, adt: impl Into<Adt>) -> Ty {
-    let adt = adt.into();
-    let adt_id: AdtId = adt.into();
-    let generics = db.generic_params(adt_id.into());
-    Ty::apply(TypeCtor::Adt(adt_id), Substs::identity(&generics))
+fn type_for_adt(db: &impl HirDatabase, adt: AdtId) -> Ty {
+    let generics = db.generic_params(adt.into());
+    Ty::apply(TypeCtor::Adt(adt), Substs::identity(&generics))
 }
 
-fn type_for_type_alias(db: &impl HirDatabase, t: TypeAlias) -> Ty {
-    let generics = db.generic_params(t.id.into());
-    let resolver = t.id.resolver(db);
-    let type_ref = t.type_ref(db);
+fn type_for_type_alias(db: &impl HirDatabase, t: TypeAliasId) -> Ty {
+    let generics = db.generic_params(t.into());
+    let resolver = t.resolver(db);
+    let type_ref = &db.type_alias_data(t).type_ref;
     let substs = Substs::identity(&generics);
-    let inner = Ty::from_hir(db, &resolver, &type_ref.unwrap_or(TypeRef::Error));
+    let inner = Ty::from_hir(db, &resolver, type_ref.as_ref().unwrap_or(&TypeRef::Error));
     inner.subst(&substs)
 }
 
@@ -808,3 +758,42 @@ impl From<CallableDef> for GenericDefId {
         }
     }
 }
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum TyDefId {
+    BuiltinType(BuiltinType),
+    AdtId(AdtId),
+    TypeAliasId(TypeAliasId),
+}
+impl_froms!(TyDefId: BuiltinType, AdtId(StructId, EnumId, UnionId), TypeAliasId);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ValueTyDefId {
+    FunctionId(FunctionId),
+    StructId(StructId),
+    EnumVariantId(EnumVariantId),
+    ConstId(ConstId),
+    StaticId(StaticId),
+}
+impl_froms!(ValueTyDefId: FunctionId, StructId, EnumVariantId, ConstId, StaticId);
+
+/// Build the declared type of an item. This depends on the namespace; e.g. for
+/// `struct Foo(usize)`, we have two types: The type of the struct itself, and
+/// the constructor function `(usize) -> Foo` which lives in the values
+/// namespace.
+pub(crate) fn ty_query(db: &impl HirDatabase, def: TyDefId) -> Ty {
+    match def {
+        TyDefId::BuiltinType(it) => type_for_builtin(it),
+        TyDefId::AdtId(it) => type_for_adt(db, it),
+        TyDefId::TypeAliasId(it) => type_for_type_alias(db, it),
+    }
+}
+pub(crate) fn value_ty_query(db: &impl HirDatabase, def: ValueTyDefId) -> Ty {
+    match def {
+        ValueTyDefId::FunctionId(it) => type_for_fn(db, it),
+        ValueTyDefId::StructId(it) => type_for_struct_constructor(db, it),
+        ValueTyDefId::EnumVariantId(it) => type_for_enum_variant_constructor(db, it),
+        ValueTyDefId::ConstId(it) => type_for_const(db, it),
+        ValueTyDefId::StaticId(it) => type_for_static(db, it),
+    }
+}
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 02d37dead..4b0f4f56c 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -786,7 +786,7 @@ fn type_alias_associated_ty_value(
         .expect("assoc ty value should not exist"); // validated when building the impl data as well
     let generic_params = db.generic_params(impl_block.id.into());
     let bound_vars = Substs::bound_vars(&generic_params);
-    let ty = db.type_for_def(type_alias.into(), crate::ty::Namespace::Types).subst(&bound_vars);
+    let ty = db.ty(type_alias.id.into()).subst(&bound_vars);
     let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty: ty.to_chalk(db) };
     let value = chalk_rust_ir::AssociatedTyValue {
         impl_id,