Support extern types

Author: jonas-schievink

Cargo.lock

@@ -557,6 +557,10 @@ impl Ctx {
                             let statik = self.lower_static(&ast)?;
                             statik.into()
                         }
+                        ast::ExternItem::TypeAlias(ty) => {
+                            let id = self.lower_type_alias(&ty)?;
+                            id.into()
+                        }
                         ast::ExternItem::MacroCall(_) => return None,
                     };
                     self.add_attrs(id.into(), attrs);

crates/hir_def/src/item_tree/lower.rs

@@ -46,6 +46,7 @@ union U { to_be: bool, not_to_be: u8 }
 enum E { V }
 
 extern {
+    type Ext;
     static EXT: u8;
     fn ext();
 }
@@ -65,6 +66,7 @@ extern {
             Baz: t v
             E: t
             EXT: v
+            Ext: t
             U: t
             ext: v
         "#]],

crates/hir_def/src/nameres/tests.rs

@@ -1380,6 +1380,7 @@ pub enum ExternItem {
     Fn(Fn),
     MacroCall(MacroCall),
     Static(Static),
+    TypeAlias(TypeAlias),
 }
 impl ast::AttrsOwner for ExternItem {}
 impl ast::NameOwner for ExternItem {}
@@ -3339,10 +3340,13 @@ impl From<MacroCall> for ExternItem {
 impl From<Static> for ExternItem {
     fn from(node: Static) -> ExternItem { ExternItem::Static(node) }
 }
+impl From<TypeAlias> for ExternItem {
+    fn from(node: TypeAlias) -> ExternItem { ExternItem::TypeAlias(node) }
+}
 impl AstNode for ExternItem {
     fn can_cast(kind: SyntaxKind) -> bool {
         match kind {
-            FN | MACRO_CALL | STATIC => true,
+            FN | MACRO_CALL | STATIC | TYPE_ALIAS => true,
             _ => false,
         }
     }
@@ -3351,6 +3355,7 @@ impl AstNode for ExternItem {
             FN => ExternItem::Fn(Fn { syntax }),
             MACRO_CALL => ExternItem::MacroCall(MacroCall { syntax }),
             STATIC => ExternItem::Static(Static { syntax }),
+            TYPE_ALIAS => ExternItem::TypeAlias(TypeAlias { syntax }),
             _ => return None,
         };
         Some(res)
@@ -3360,6 +3365,7 @@ impl AstNode for ExternItem {
             ExternItem::Fn(it) => &it.syntax,
             ExternItem::MacroCall(it) => &it.syntax,
             ExternItem::Static(it) => &it.syntax,
+            ExternItem::TypeAlias(it) => &it.syntax,
         }
     }
 }

crates/syntax/src/ast/generated/nodes.rs

@@ -15,7 +15,7 @@ flate2 = "1.0"
 pico-args = "0.3.1"
 proc-macro2 = "1.0.8"
 quote = "1.0.2"
-ungrammar = "1.1.1"
+ungrammar = "1.1.3"
 walkdir = "2.3.1"
 write-json =  "0.1.0"
 # Avoid adding more dependencies to this crate