10 files changed, 89 insertions, 29 deletions

diff --git a/crates/completion/src/completions/qualified_path.rs b/crates/completion/src/completions/qualified_path.rs
index bbeaab496..2afa6979e 100644
--- a/crates/completion/src/completions/qualified_path.rs
+++ b/crates/completion/src/completions/qualified_path.rs
@@ -50,7 +50,8 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
             }
         }
         PathResolution::Def(def @ hir::ModuleDef::Adt(_))
-        | PathResolution::Def(def @ hir::ModuleDef::TypeAlias(_)) => {
+        | PathResolution::Def(def @ hir::ModuleDef::TypeAlias(_))
+        | PathResolution::Def(def @ hir::ModuleDef::BuiltinType(_)) => {
             if let hir::ModuleDef::Adt(Adt::Enum(e)) = def {
                 for variant in e.variants(ctx.db) {
                     acc.add_enum_variant(ctx, variant, None);
@@ -59,6 +60,13 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
             let ty = match def {
                 hir::ModuleDef::Adt(adt) => adt.ty(ctx.db),
                 hir::ModuleDef::TypeAlias(a) => a.ty(ctx.db),
+                hir::ModuleDef::BuiltinType(builtin) => {
+                    let module = match ctx.scope.module() {
+                        Some(it) => it,
+                        None => return,
+                    };
+                    builtin.ty(ctx.db, module)
+                }
                 _ => unreachable!(),
             };
 
@@ -780,4 +788,28 @@ impl Foo {
             "#]],
         );
     }
+
+    #[test]
+    fn completes_primitive_assoc_const() {
+        check(
+            r#"
+//- /lib.rs crate:lib deps:core
+fn f() {
+    u8::$0
+}
+
+//- /core.rs crate:core
+#[lang = "u8"]
+impl u8 {
+    pub const MAX: Self = 255;
+
+    pub fn func(self) {}
+}
+"#,
+            expect![[r#"
+                ct MAX     pub const MAX: Self = 255;
+                me func(…) -> ()
+            "#]],
+        );
+    }
 }
diff --git a/crates/hir/src/code_model.rs b/crates/hir/src/code_model.rs
index e9bb4f541..35b532602 100644
--- a/crates/hir/src/code_model.rs
+++ b/crates/hir/src/code_model.rs
@@ -6,7 +6,6 @@ use base_db::{CrateDisplayName, CrateId, Edition, FileId};
 use either::Either;
 use hir_def::{
     adt::{ReprKind, StructKind, VariantData},
-    builtin_type::BuiltinType,
     expr::{BindingAnnotation, LabelId, Pat, PatId},
     import_map,
     item_tree::ItemTreeNode,
@@ -245,7 +244,7 @@ impl ModuleDef {
             ModuleDef::Const(it) => it.name(db),
             ModuleDef::Static(it) => it.name(db),
 
-            ModuleDef::BuiltinType(it) => Some(it.as_name()),
+            ModuleDef::BuiltinType(it) => Some(it.name()),
         }
     }
 
@@ -995,6 +994,23 @@ impl HasVisibility for TypeAlias {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct BuiltinType {
+    pub(crate) inner: hir_def::builtin_type::BuiltinType,
+}
+
+impl BuiltinType {
+    pub fn ty(self, db: &dyn HirDatabase, module: Module) -> Type {
+        let resolver = module.id.resolver(db.upcast());
+        Type::new_with_resolver(db, &resolver, Ty::builtin(self.inner))
+            .expect("crate not present in resolver")
+    }
+
+    pub fn name(self) -> Name {
+        self.inner.as_name()
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct MacroDef {
     pub(crate) id: MacroDefId,
 }
diff --git a/crates/hir/src/from_id.rs b/crates/hir/src/from_id.rs
index c8c5fecd7..b5814da11 100644
--- a/crates/hir/src/from_id.rs
+++ b/crates/hir/src/from_id.rs
@@ -11,8 +11,9 @@ use hir_def::{
 };
 
 use crate::{
-    code_model::GenericParam, Adt, AssocItem, DefWithBody, Field, GenericDef, Label, Local,
-    MacroDef, ModuleDef, Variant, VariantDef,
+    code_model::{BuiltinType, GenericParam},
+    Adt, AssocItem, DefWithBody, Field, GenericDef, Label, Local, MacroDef, ModuleDef, Variant,
+    VariantDef,
 };
 
 macro_rules! from_id {
@@ -111,7 +112,7 @@ impl From<ModuleDefId> for ModuleDef {
             ModuleDefId::StaticId(it) => ModuleDef::Static(it.into()),
             ModuleDefId::TraitId(it) => ModuleDef::Trait(it.into()),
             ModuleDefId::TypeAliasId(it) => ModuleDef::TypeAlias(it.into()),
-            ModuleDefId::BuiltinType(it) => ModuleDef::BuiltinType(it),
+            ModuleDefId::BuiltinType(it) => ModuleDef::BuiltinType(it.into()),
         }
     }
 }
@@ -127,7 +128,7 @@ impl From<ModuleDef> for ModuleDefId {
             ModuleDef::Static(it) => ModuleDefId::StaticId(it.into()),
             ModuleDef::Trait(it) => ModuleDefId::TraitId(it.into()),
             ModuleDef::TypeAlias(it) => ModuleDefId::TypeAliasId(it.into()),
-            ModuleDef::BuiltinType(it) => ModuleDefId::BuiltinType(it),
+            ModuleDef::BuiltinType(it) => ModuleDefId::BuiltinType(it.into()),
         }
     }
 }
@@ -274,3 +275,15 @@ impl From<ModuleDef> for ItemInNs {
         }
     }
 }
+
+impl From<hir_def::builtin_type::BuiltinType> for BuiltinType {
+    fn from(inner: hir_def::builtin_type::BuiltinType) -> Self {
+        Self { inner }
+    }
+}
+
+impl From<BuiltinType> for hir_def::builtin_type::BuiltinType {
+    fn from(it: BuiltinType) -> Self {
+        it.inner
+    }
+}
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 0a30b4f5b..59292d5a2 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -49,7 +49,7 @@ impl PathResolution {
         match self {
             PathResolution::Def(ModuleDef::Adt(adt)) => Some(TypeNs::AdtId((*adt).into())),
             PathResolution::Def(ModuleDef::BuiltinType(builtin)) => {
-                Some(TypeNs::BuiltinType(*builtin))
+                Some(TypeNs::BuiltinType((*builtin).into()))
             }
             PathResolution::Def(ModuleDef::Const(_))
             | PathResolution::Def(ModuleDef::Variant(_))
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index bed3fa50f..dc21f6051 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -28,8 +28,9 @@ use syntax::{
 };
 
 use crate::{
-    db::HirDatabase, semantics::PathResolution, Adt, Const, Field, Function, Local, MacroDef,
-    ModuleDef, Static, Struct, Trait, Type, TypeAlias, TypeParam, Variant,
+    code_model::BuiltinType, db::HirDatabase, semantics::PathResolution, Adt, Const, Field,
+    Function, Local, MacroDef, ModuleDef, Static, Struct, Trait, Type, TypeAlias, TypeParam,
+    Variant,
 };
 use base_db::CrateId;
 
@@ -479,7 +480,7 @@ fn resolve_hir_path_(
             }
             TypeNs::EnumVariantId(it) => PathResolution::Def(Variant::from(it).into()),
             TypeNs::TypeAliasId(it) => PathResolution::Def(TypeAlias::from(it).into()),
-            TypeNs::BuiltinType(it) => PathResolution::Def(it.into()),
+            TypeNs::BuiltinType(it) => PathResolution::Def(BuiltinType::from(it).into()),
             TypeNs::TraitId(it) => PathResolution::Def(Trait::from(it).into()),
         })
     };
@@ -555,7 +556,7 @@ fn resolve_hir_path_qualifier(
         TypeNs::AdtSelfType(it) | TypeNs::AdtId(it) => PathResolution::Def(Adt::from(it).into()),
         TypeNs::EnumVariantId(it) => PathResolution::Def(Variant::from(it).into()),
         TypeNs::TypeAliasId(it) => PathResolution::Def(TypeAlias::from(it).into()),
-        TypeNs::BuiltinType(it) => PathResolution::Def(it.into()),
+        TypeNs::BuiltinType(it) => PathResolution::Def(BuiltinType::from(it).into()),
         TypeNs::TraitId(it) => PathResolution::Def(Trait::from(it).into()),
     })
 }
diff --git a/crates/hir_def/src/resolver.rs b/crates/hir_def/src/resolver.rs
index a8467c88e..e85f85e49 100644
--- a/crates/hir_def/src/resolver.rs
+++ b/crates/hir_def/src/resolver.rs
@@ -361,6 +361,7 @@ impl Resolver {
     }
 
     pub fn krate(&self) -> Option<CrateId> {
+        // FIXME: can this ever be `None`?
         self.module_scope().map(|t| t.0.krate())
     }
 
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 6bec389f8..50d248674 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -27,6 +27,7 @@ use std::{iter, mem, ops::Deref, sync::Arc};
 
 use base_db::{salsa, CrateId};
 use hir_def::{
+    builtin_type::BuiltinType,
     expr::ExprId,
     type_ref::{Mutability, Rawness},
     AdtId, AssocContainerId, DefWithBodyId, FunctionId, GenericDefId, HasModule, LifetimeParamId,
@@ -738,6 +739,15 @@ impl Ty {
             Substs(sig.params_and_return),
         )
     }
+    pub fn builtin(builtin: BuiltinType) -> Self {
+        Ty::simple(match builtin {
+            BuiltinType::Char => TypeCtor::Char,
+            BuiltinType::Bool => TypeCtor::Bool,
+            BuiltinType::Str => TypeCtor::Str,
+            BuiltinType::Int(t) => TypeCtor::Int(IntTy::from(t).into()),
+            BuiltinType::Float(t) => TypeCtor::Float(FloatTy::from(t).into()),
+        })
+    }
 
     pub fn as_reference(&self) -> Option<(&Ty, Mutability)> {
         match self {
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index dfb573ff3..f9dc832bd 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -27,7 +27,6 @@ use test_utils::mark;
 
 use crate::{
     db::HirDatabase,
-    primitive::{FloatTy, IntTy},
     utils::{
         all_super_trait_refs, associated_type_by_name_including_super_traits, generics,
         make_mut_slice, variant_data,
@@ -1051,17 +1050,6 @@ fn type_for_static(db: &dyn HirDatabase, def: StaticId) -> Binders<Ty> {
     Binders::new(0, Ty::from_hir(&ctx, &data.type_ref))
 }
 
-/// Build the declared type of a static.
-fn type_for_builtin(def: BuiltinType) -> Ty {
-    Ty::simple(match def {
-        BuiltinType::Char => TypeCtor::Char,
-        BuiltinType::Bool => TypeCtor::Bool,
-        BuiltinType::Str => TypeCtor::Str,
-        BuiltinType::Int(t) => TypeCtor::Int(IntTy::from(t).into()),
-        BuiltinType::Float(t) => TypeCtor::Float(FloatTy::from(t).into()),
-    })
-}
-
 fn fn_sig_for_struct_constructor(db: &dyn HirDatabase, def: StructId) -> PolyFnSig {
     let struct_data = db.struct_data(def);
     let fields = struct_data.variant_data.fields();
@@ -1186,7 +1174,7 @@ impl_from!(FunctionId, StructId, UnionId, EnumVariantId, ConstId, StaticId for V
 /// namespace.
 pub(crate) fn ty_query(db: &dyn HirDatabase, def: TyDefId) -> Binders<Ty> {
     match def {
-        TyDefId::BuiltinType(it) => Binders::new(0, type_for_builtin(it)),
+        TyDefId::BuiltinType(it) => Binders::new(0, Ty::builtin(it)),
         TyDefId::AdtId(it) => type_for_adt(db, it),
         TyDefId::TypeAliasId(it) => type_for_type_alias(db, it),
     }
diff --git a/crates/ide/src/doc_links.rs b/crates/ide/src/doc_links.rs
index 730e0dd0a..f94adec9b 100644
--- a/crates/ide/src/doc_links.rs
+++ b/crates/ide/src/doc_links.rs
@@ -9,8 +9,7 @@ use url::Url;
 
 use hir::{
     db::{DefDatabase, HirDatabase},
-    Adt, AsAssocItem, AsName, AssocItem, AssocItemContainer, Crate, Field, HasAttrs, ItemInNs,
-    ModuleDef,
+    Adt, AsAssocItem, AssocItem, AssocItemContainer, Crate, Field, HasAttrs, ItemInNs, ModuleDef,
 };
 use ide_db::{
     defs::{Definition, NameClass, NameRefClass},
@@ -429,7 +428,7 @@ fn get_symbol_filename(db: &dyn HirDatabase, definition: &ModuleDef) -> Option<S
         ModuleDef::Module(_) => "index.html".to_string(),
         ModuleDef::Trait(t) => format!("trait.{}.html", t.name(db)),
         ModuleDef::TypeAlias(t) => format!("type.{}.html", t.name(db)),
-        ModuleDef::BuiltinType(t) => format!("primitive.{}.html", t.as_name()),
+        ModuleDef::BuiltinType(t) => format!("primitive.{}.html", t.name()),
         ModuleDef::Function(f) => format!("fn.{}.html", f.name(db)),
         ModuleDef::Variant(ev) => {
             format!("enum.{}.html#variant.{}", ev.parent_enum(db).name(db), ev.name(db))
diff --git a/crates/ide/src/hover.rs b/crates/ide/src/hover.rs
index 5d2d072b1..00745238a 100644
--- a/crates/ide/src/hover.rs
+++ b/crates/ide/src/hover.rs
@@ -334,7 +334,7 @@ fn hover_for_definition(db: &RootDatabase, def: Definition) -> Option<Markup> {
             ModuleDef::Static(it) => from_def_source(db, it, mod_path),
             ModuleDef::Trait(it) => from_def_source(db, it, mod_path),
             ModuleDef::TypeAlias(it) => from_def_source(db, it, mod_path),
-            ModuleDef::BuiltinType(it) => Some(Markup::fenced_block(&it)),
+            ModuleDef::BuiltinType(it) => Some(Markup::fenced_block(&it.name())),
         },
         Definition::Local(it) => Some(Markup::fenced_block(&it.ty(db).display(db))),
         Definition::SelfType(impl_def) => {