9 files changed, 91 insertions, 26 deletions

diff --git a/crates/ra_hir/src/adt.rs b/crates/ra_hir/src/adt.rs
index e027eedd9..5e5905f15 100644
--- a/crates/ra_hir/src/adt.rs
+++ b/crates/ra_hir/src/adt.rs
@@ -10,7 +10,7 @@ use ra_syntax::{
 };
 
 use crate::{
-    Name, AsName, Struct, Enum, EnumVariant, Crate,
+    Name, AsName, Struct, Union, Enum, EnumVariant, Crate,
     HirDatabase, HirFileId, StructField, FieldSource,
     type_ref::TypeRef, DefDatabase,
 };
@@ -18,14 +18,16 @@ use crate::{
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum AdtDef {
     Struct(Struct),
+    Union(Union),
     Enum(Enum),
 }
-impl_froms!(AdtDef: Struct, Enum);
+impl_froms!(AdtDef: Struct, Union, Enum);
 
 impl AdtDef {
     pub(crate) fn krate(self, db: &impl HirDatabase) -> Option<Crate> {
         match self {
             AdtDef::Struct(s) => s.module(db),
+            AdtDef::Union(s) => s.module(db),
             AdtDef::Enum(e) => e.module(db),
         }
         .krate(db)
@@ -38,6 +40,7 @@ impl Struct {
     }
 }
 
+/// Note that we use `StructData` for unions as well!
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct StructData {
     pub(crate) name: Option<Name>,
diff --git a/crates/ra_hir/src/code_model_api.rs b/crates/ra_hir/src/code_model_api.rs
index 0c4a80bfa..970b78412 100644
--- a/crates/ra_hir/src/code_model_api.rs
+++ b/crates/ra_hir/src/code_model_api.rs
@@ -71,6 +71,7 @@ pub enum ModuleDef {
     Module(Module),
     Function(Function),
     Struct(Struct),
+    Union(Union),
     Enum(Enum),
     // Can't be directly declared, but can be imported.
     EnumVariant(EnumVariant),
@@ -83,6 +84,7 @@ impl_froms!(
     ModuleDef: Module,
     Function,
     Struct,
+    Union,
     Enum,
     EnumVariant,
     Const,
@@ -326,6 +328,42 @@ impl Docs for Struct {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Union {
+    pub(crate) id: StructId,
+}
+
+impl Union {
+    pub fn source(&self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::StructDef>) {
+        self.id.source(db)
+    }
+
+    pub fn name(&self, db: &impl HirDatabase) -> Option<Name> {
+        db.struct_data(Struct { id: self.id }).name.clone()
+    }
+
+    pub fn module(&self, db: &impl HirDatabase) -> Module {
+        self.id.module(db)
+    }
+
+    // FIXME move to a more general type
+    /// Builds a resolver for type references inside this union.
+    pub(crate) fn resolver(&self, db: &impl HirDatabase) -> Resolver {
+        // take the outer scope...
+        let r = self.module(db).resolver(db);
+        // ...and add generic params, if present
+        let p = self.generic_params(db);
+        let r = if !p.params.is_empty() { r.push_generic_params_scope(p) } else { r };
+        r
+    }
+}
+
+impl Docs for Union {
+    fn docs(&self, db: &impl HirDatabase) -> Option<Documentation> {
+        docs_from_ast(&*self.source(db).1)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Enum {
     pub(crate) id: EnumId,
 }
diff --git a/crates/ra_hir/src/generics.rs b/crates/ra_hir/src/generics.rs
index 79a7fa23a..8effbbe35 100644
--- a/crates/ra_hir/src/generics.rs
+++ b/crates/ra_hir/src/generics.rs
@@ -9,7 +9,7 @@ use ra_syntax::ast::{self, NameOwner, TypeParamsOwner, TypeBoundsOwner, DefaultT
 
 use crate::{
     db::{ HirDatabase, DefDatabase},
-    Name, AsName, Function, Struct, Enum, Trait, TypeAlias, ImplBlock, Container, path::Path, type_ref::TypeRef, AdtDef
+    Name, AsName, Function, Struct, Union, Enum, Trait, TypeAlias, ImplBlock, Container, path::Path, type_ref::TypeRef, AdtDef
 };
 
 /// Data about a generic parameter (to a function, struct, impl, ...).
@@ -42,12 +42,13 @@ pub struct WherePredicate {
 pub enum GenericDef {
     Function(Function),
     Struct(Struct),
+    Union(Union),
     Enum(Enum),
     Trait(Trait),
     TypeAlias(TypeAlias),
     ImplBlock(ImplBlock),
 }
-impl_froms!(GenericDef: Function, Struct, Enum, Trait, TypeAlias, ImplBlock);
+impl_froms!(GenericDef: Function, Struct, Union, Enum, Trait, TypeAlias, ImplBlock);
 
 impl GenericParams {
     pub(crate) fn generic_params_query(
@@ -58,7 +59,10 @@ impl GenericParams {
         let parent = match def {
             GenericDef::Function(it) => it.container(db).map(GenericDef::from),
             GenericDef::TypeAlias(it) => it.container(db).map(GenericDef::from),
-            GenericDef::Struct(_) | GenericDef::Enum(_) | GenericDef::Trait(_) => None,
+            GenericDef::Struct(_)
+            | GenericDef::Union(_)
+            | GenericDef::Enum(_)
+            | GenericDef::Trait(_) => None,
             GenericDef::ImplBlock(_) => None,
         };
         generics.parent_params = parent.map(|p| db.generic_params(p));
@@ -66,6 +70,7 @@ impl GenericParams {
         match def {
             GenericDef::Function(it) => generics.fill(&*it.source(db).1, start),
             GenericDef::Struct(it) => generics.fill(&*it.source(db).1, start),
+            GenericDef::Union(it) => generics.fill(&*it.source(db).1, start),
             GenericDef::Enum(it) => generics.fill(&*it.source(db).1, start),
             GenericDef::Trait(it) => {
                 // traits get the Self type as an implicit first type parameter
@@ -171,6 +176,7 @@ impl GenericDef {
         match self {
             GenericDef::Function(inner) => inner.resolver(db),
             GenericDef::Struct(inner) => inner.resolver(db),
+            GenericDef::Union(inner) => inner.resolver(db),
             GenericDef::Enum(inner) => inner.resolver(db),
             GenericDef::Trait(inner) => inner.resolver(db),
             GenericDef::TypeAlias(inner) => inner.resolver(db),
@@ -192,6 +198,7 @@ impl From<crate::adt::AdtDef> for GenericDef {
     fn from(adt: crate::adt::AdtDef) -> Self {
         match adt {
             AdtDef::Struct(s) => s.into(),
+            AdtDef::Union(u) => u.into(),
             AdtDef::Enum(e) => e.into(),
         }
     }
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 0c6d7c2b7..0135644db 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -77,7 +77,7 @@ pub use self::code_model_api::{
     Crate, CrateDependency,
     DefWithBody,
     Module, ModuleDef, ModuleSource,
-    Struct, Enum, EnumVariant,
+    Struct, Union, Enum, EnumVariant,
     Function, FnSignature,
     StructField, FieldSource,
     Static, Const, ConstSignature,
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index c615d80c3..621236551 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -6,7 +6,7 @@ use ra_db::FileId;
 use ra_syntax::ast;
 
 use crate::{
-    Function, Module, Struct, Enum, Const, Static, Trait, TypeAlias,
+    Function, Module, Struct, Union, Enum, Const, Static, Trait, TypeAlias,
     DefDatabase, HirFileId, Name, Path,
     KnownName,
     nameres::{
@@ -495,6 +495,10 @@ where
                 let s = def!(Struct, ast_id);
                 PerNs::both(s, s)
             }
+            raw::DefKind::Union(ast_id) => {
+                let s = def!(Union, ast_id);
+                PerNs::both(s, s)
+            }
             raw::DefKind::Enum(ast_id) => PerNs::types(def!(Enum, ast_id)),
             raw::DefKind::Const(ast_id) => PerNs::values(def!(Const, ast_id)),
             raw::DefKind::Static(ast_id) => PerNs::values(def!(Static, ast_id)),
diff --git a/crates/ra_hir/src/nameres/raw.rs b/crates/ra_hir/src/nameres/raw.rs
index bd32b264b..1b4dcbb7a 100644
--- a/crates/ra_hir/src/nameres/raw.rs
+++ b/crates/ra_hir/src/nameres/raw.rs
@@ -1,7 +1,4 @@
-use std::{
-    sync::Arc,
-    ops::Index,
-};
+use std::{sync::Arc, ops::Index};
 
 use test_utils::tested_by;
 use ra_arena::{Arena, impl_arena_id, RawId, map::ArenaMap};
@@ -10,10 +7,7 @@ use ra_syntax::{
     ast::{self, NameOwner, AttrsOwner},
 };
 
-use crate::{
-    DefDatabase, Name, AsName, Path, HirFileId, ModuleSource,
-    AstIdMap, FileAstId, Either,
-};
+use crate::{DefDatabase, Name, AsName, Path, HirFileId, ModuleSource, AstIdMap, FileAstId, Either};
 
 /// `RawItems` is a set of top-level items in a file (except for impls).
 ///
@@ -161,6 +155,7 @@ pub(super) struct DefData {
 pub(super) enum DefKind {
     Function(FileAstId<ast::FnDef>),
     Struct(FileAstId<ast::StructDef>),
+    Union(FileAstId<ast::StructDef>),
     Enum(FileAstId<ast::EnumDef>),
     Const(FileAstId<ast::ConstDef>),
     Static(FileAstId<ast::StaticDef>),
@@ -215,7 +210,13 @@ impl RawItemsCollector {
                 return;
             }
             ast::ModuleItemKind::StructDef(it) => {
-                (DefKind::Struct(self.source_ast_id_map.ast_id(it)), it.name())
+                let id = self.source_ast_id_map.ast_id(it);
+                let name = it.name();
+                if it.is_union() {
+                    (DefKind::Union(id), name)
+                } else {
+                    (DefKind::Struct(id), name)
+                }
             }
             ast::ModuleItemKind::EnumDef(it) => {
                 (DefKind::Enum(self.source_ast_id_map.ast_id(it)), it.name())
diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index 3679a2242..76d34c12b 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -536,6 +536,7 @@ impl HirDisplay for ApplicationTy {
             TypeCtor::Adt(def_id) => {
                 let name = match def_id {
                     AdtDef::Struct(s) => s.name(f.db),
+                    AdtDef::Union(u) => u.name(f.db),
                     AdtDef::Enum(e) => e.name(f.db),
                 }
                 .unwrap_or_else(Name::missing);
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index a48272981..7d8250292 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -27,13 +27,13 @@ use ra_prof::profile;
 use test_utils::tested_by;
 
 use crate::{
-    Function, StructField, Path, Name,
-    FnSignature, AdtDef,ConstSignature,
-    HirDatabase,
-    DefWithBody,
-    ImplItem,
+    Function, StructField, Path, Name, FnSignature, AdtDef, ConstSignature, HirDatabase,
+    DefWithBody, ImplItem,
     type_ref::{TypeRef, Mutability},
-    expr::{Body, Expr, BindingAnnotation, Literal, ExprId, Pat, PatId, UnaryOp, BinaryOp, Statement, FieldPat,Array, self},
+    expr::{
+        Body, Expr, BindingAnnotation, Literal, ExprId, Pat, PatId, UnaryOp, BinaryOp, Statement,
+        FieldPat, Array, self,
+    },
     generics::{GenericParams, HasGenericParams},
     path::{GenericArgs, GenericArg},
     ModuleDef,
@@ -644,7 +644,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 let ty = self.insert_type_vars(ty.apply_substs(substs));
                 (ty, Some(var.into()))
             }
-            TypableDef::TypeAlias(_)
+            TypableDef::Union(_)
+            | TypableDef::TypeAlias(_)
             | TypableDef::Function(_)
             | TypableDef::Enum(_)
             | TypableDef::Const(_)
@@ -1407,7 +1408,11 @@ impl Expectation {
 }
 
 mod diagnostics {
-    use crate::{expr::ExprId, diagnostics::{DiagnosticSink, NoSuchField}, HirDatabase, Function};
+    use crate::{
+        expr::ExprId,
+        diagnostics::{DiagnosticSink, NoSuchField},
+        HirDatabase, Function,
+};
 
     #[derive(Debug, PartialEq, Eq, Clone)]
     pub(super) enum InferenceDiagnostic {
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index a1a2d0f6b..7defa7a9b 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -9,7 +9,7 @@ use std::sync::Arc;
 use std::iter;
 
 use crate::{
-    Function, Struct, StructField, Enum, EnumVariant, Path, ModuleDef, TypeAlias, Const, Static,
+    Function, Struct, Union, StructField, Enum, EnumVariant, Path, ModuleDef, TypeAlias, Const, Static,
     HirDatabase,
     type_ref::TypeRef,
     name::KnownName,
@@ -124,6 +124,7 @@ impl Ty {
         let def_generic: Option<GenericDef> = match resolved {
             TypableDef::Function(func) => Some(func.into()),
             TypableDef::Struct(s) => Some(s.into()),
+            TypableDef::Union(u) => Some(u.into()),
             TypableDef::Enum(e) => Some(e.into()),
             TypableDef::EnumVariant(var) => Some(var.parent_enum(db).into()),
             TypableDef::TypeAlias(t) => Some(t.into()),
@@ -144,6 +145,7 @@ impl Ty {
         let segment = match resolved {
             TypableDef::Function(_)
             | TypableDef::Struct(_)
+            | TypableDef::Union(_)
             | TypableDef::Enum(_)
             | TypableDef::Const(_)
             | TypableDef::Static(_)
@@ -293,12 +295,14 @@ pub(crate) fn type_for_def(db: &impl HirDatabase, def: TypableDef, ns: Namespace
         (TypableDef::Struct(s), Namespace::Values) => type_for_struct_constructor(db, s),
         (TypableDef::Enum(e), Namespace::Types) => type_for_adt(db, e),
         (TypableDef::EnumVariant(v), Namespace::Values) => type_for_enum_variant_constructor(db, v),
+        (TypableDef::Union(u), Namespace::Types) => type_for_adt(db, u),
         (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),
 
         // 'error' cases:
         (TypableDef::Function(_), Namespace::Types) => Ty::Unknown,
+        (TypableDef::Union(_), Namespace::Values) => Ty::Unknown,
         (TypableDef::Enum(_), Namespace::Values) => Ty::Unknown,
         (TypableDef::EnumVariant(_), Namespace::Types) => Ty::Unknown,
         (TypableDef::TypeAlias(_), Namespace::Values) => Ty::Unknown,
@@ -467,19 +471,21 @@ fn type_for_type_alias(db: &impl HirDatabase, t: TypeAlias) -> Ty {
 pub enum TypableDef {
     Function(Function),
     Struct(Struct),
+    Union(Union),
     Enum(Enum),
     EnumVariant(EnumVariant),
     TypeAlias(TypeAlias),
     Const(Const),
     Static(Static),
 }
-impl_froms!(TypableDef: Function, Struct, Enum, EnumVariant, TypeAlias, Const, Static);
+impl_froms!(TypableDef: Function, Struct, Union, Enum, EnumVariant, TypeAlias, Const, Static);
 
 impl From<ModuleDef> for Option<TypableDef> {
     fn from(def: ModuleDef) -> Option<TypableDef> {
         let res = match def {
             ModuleDef::Function(f) => f.into(),
             ModuleDef::Struct(s) => s.into(),
+            ModuleDef::Union(u) => u.into(),
             ModuleDef::Enum(e) => e.into(),
             ModuleDef::EnumVariant(v) => v.into(),
             ModuleDef::TypeAlias(t) => t.into(),