Add support for unions in inference and lowering

crates/ra_hir_ty/src/infer.rs

@@ -440,6 +440,12 @@ impl<'a> InferenceContext<'a> {
                 let ty = self.insert_type_vars(ty.subst(&substs));
                 forbid_unresolved_segments((ty, Some(strukt.into())), unresolved)
             }
+            TypeNs::AdtId(AdtId::UnionId(u)) => {
+                let substs = Ty::substs_from_path(&ctx, path, u.into(), true);
+                let ty = self.db.ty(u.into());
+                let ty = self.insert_type_vars(ty.subst(&substs));
+                forbid_unresolved_segments((ty, Some(u.into())), unresolved)
+            }
             TypeNs::EnumVariantId(var) => {
                 let substs = Ty::substs_from_path(&ctx, path, var.into(), true);
                 let ty = self.db.ty(var.parent.into());
@@ -490,10 +496,7 @@ impl<'a> InferenceContext<'a> {
                 // FIXME potentially resolve assoc type
                 (Ty::Unknown, None)
             }
-            TypeNs::AdtId(AdtId::EnumId(_))
+            TypeNs::AdtId(AdtId::EnumId(_)) | TypeNs::BuiltinType(_) | TypeNs::TraitId(_) => {
-            | TypeNs::AdtId(AdtId::UnionId(_))
-            | TypeNs::BuiltinType(_)
-            | TypeNs::TraitId(_) => {
                 // FIXME diagnostic
                 (Ty::Unknown, None)
             }

crates/ra_hir_ty/src/lower.rs

@@ -518,6 +518,7 @@ impl Ty {
         let (segment, generic_def) = match resolved {
             ValueTyDefId::FunctionId(it) => (last, Some(it.into())),
             ValueTyDefId::StructId(it) => (last, Some(it.into())),
+            ValueTyDefId::UnionId(it) => (last, Some(it.into())),
             ValueTyDefId::ConstId(it) => (last, Some(it.into())),
             ValueTyDefId::StaticId(_) => (last, None),
             ValueTyDefId::EnumVariantId(var) => {
@@ -1148,11 +1149,12 @@ impl_from!(BuiltinType, AdtId(StructId, EnumId, UnionId), TypeAliasId for TyDefI
 pub enum ValueTyDefId {
     FunctionId(FunctionId),
     StructId(StructId),
+    UnionId(UnionId),
     EnumVariantId(EnumVariantId),
     ConstId(ConstId),
     StaticId(StaticId),
 }
-impl_from!(FunctionId, StructId, EnumVariantId, ConstId, StaticId for ValueTyDefId);
+impl_from!(FunctionId, StructId, UnionId, EnumVariantId, ConstId, StaticId for ValueTyDefId);
 
 /// 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
@@ -1179,6 +1181,7 @@ pub(crate) fn value_ty_query(db: &dyn HirDatabase, def: ValueTyDefId) -> Binders
     match def {
         ValueTyDefId::FunctionId(it) => type_for_fn(db, it),
         ValueTyDefId::StructId(it) => type_for_struct_constructor(db, it),
+        ValueTyDefId::UnionId(it) => type_for_adt(db, it.into()),
         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),

crates/ra_hir_ty/src/tests/simple.rs

@@ -350,7 +350,7 @@ fn infer_union() {
             57..172 '{     ...); } }': ()
             67..68 'u': MyUnion
             71..89 'MyUnio...o: 0 }': MyUnion
-            86..87 '0': i32
+            86..87 '0': u32
             95..113 'unsafe...(u); }': ()
             102..113 '{ baz(u); }': ()
             104..107 'baz': fn baz(MyUnion)
@@ -358,7 +358,7 @@ fn infer_union() {
             108..109 'u': MyUnion
             122..123 'u': MyUnion
             126..146 'MyUnio... 0.0 }': MyUnion
-            141..144 '0.0': f64
+            141..144 '0.0': f32
             152..170 'unsafe...(u); }': ()
             159..170 '{ baz(u); }': ()
             161..164 'baz': fn baz(MyUnion)

crates/ra_ide/test_data/highlight_unsafe.html

@@ -50,13 +50,13 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 <span class="keyword">fn</span> <span class="function declaration">main</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span>
     <span class="keyword">let</span> <span class="variable declaration">x</span> <span class="operator">=</span> <span class="operator">&</span><span class="numeric_literal">5</span> <span class="keyword">as</span> <span class="keyword">*</span><span class="keyword">const</span> <span class="builtin_type">usize</span><span class="punctuation">;</span>
-    <span class="keyword">let</span> <span class="variable declaration">u</span> <span class="operator">=</span> <span class="union">Union</span> <span class="punctuation">{</span> <span class="unresolved_reference">b</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">u</span> <span class="operator">=</span> <span class="union">Union</span> <span class="punctuation">{</span> <span class="field">b</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
     <span class="keyword unsafe">unsafe</span> <span class="punctuation">{</span>
         <span class="function unsafe">unsafe_fn</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
-        <span class="keyword">let</span> <span class="variable declaration">b</span> <span class="operator">=</span> <span class="variable">u</span><span class="punctuation">.</span><span class="unresolved_reference">b</span><span class="punctuation">;</span>
+        <span class="keyword">let</span> <span class="variable declaration">b</span> <span class="operator">=</span> <span class="variable">u</span><span class="punctuation">.</span><span class="field">b</span><span class="punctuation">;</span>
         <span class="keyword control">match</span> <span class="variable">u</span> <span class="punctuation">{</span>
-            <span class="union">Union</span> <span class="punctuation">{</span> <span class="unresolved_reference">b</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span> <span class="operator">=&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">,</span>
+            <span class="union">Union</span> <span class="punctuation">{</span> <span class="field">b</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span> <span class="operator">=&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">,</span>
-            <span class="union">Union</span> <span class="punctuation">{</span> <span class="variable declaration">a</span> <span class="punctuation">}</span> <span class="operator">=&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">,</span>
+            <span class="union">Union</span> <span class="punctuation">{</span> <span class="field">a</span> <span class="punctuation">}</span> <span class="operator">=&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">,</span>
         <span class="punctuation">}</span>
         <span class="struct">HasUnsafeFn</span><span class="punctuation">.</span><span class="function unsafe">unsafe_method</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
         <span class="keyword">let</span> <span class="variable declaration">y</span> <span class="operator">=</span> <span class="operator unsafe">*</span><span class="punctuation">(</span><span class="variable">x</span><span class="punctuation">)</span><span class="punctuation">;</span>