Merge #1290

1290: Add Union to code_model r=matklad a=matklad

@flodiebold I am conflicted about two possible implementation approaches:

* we can add a separate `struct Union` to code model
* we can add `fn is_union(&self)` to existing `Struct`

This PR goes with the former approach, because it seems like Unions are sufficiently different in semantics to warrant a separate types. Which is in contrast to Syntax Tree, where both structs and unions share the same node kind, because their syntax is the same. 

What would be the right thing to do here?

Co-authored-by: Aleksey Kladov <[email protected]>

2 files changed, 15 insertions, 10 deletions

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())