separete structure from symbols

crates/libsyntax2/src/ast/generated.rs

@@ -86,6 +86,24 @@ impl<R: TreeRoot> AstNode<R> for FnDef<R> {
 impl<R: TreeRoot> ast::NameOwner<R> for FnDef<R> {}
 impl<R: TreeRoot> FnDef<R> {}
 
+// ImplItem
+#[derive(Debug, Clone, Copy)]
+pub struct ImplItem<R: TreeRoot = Arc<SyntaxRoot>> {
+    syntax: SyntaxNode<R>,
+}
+
+impl<R: TreeRoot> AstNode<R> for ImplItem<R> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self> {
+        match syntax.kind() {
+            IMPL_ITEM => Some(ImplItem { syntax }),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode<R> { &self.syntax }
+}
+
+impl<R: TreeRoot> ImplItem<R> {}
+
 // Module
 #[derive(Debug, Clone, Copy)]
 pub struct Module<R: TreeRoot = Arc<SyntaxRoot>> {

crates/libsyntax2/src/ast/mod.rs

@@ -10,8 +10,9 @@ use {
 };
 pub use self::generated::*;
 
-pub trait AstNode<R: TreeRoot>: Sized {
-    fn cast(syntax: SyntaxNode<R>) -> Option<Self>;
+pub trait AstNode<R: TreeRoot> {
+    fn cast(syntax: SyntaxNode<R>) -> Option<Self>
+        where Self: Sized;
     fn syntax(&self) -> &SyntaxNode<R>;
 }
 

crates/libsyntax2/src/grammar.ron

@@ -229,6 +229,7 @@ Grammar(
         "ConstDef": ( traits: ["NameOwner"] ),
         "StaticDef": ( traits: ["NameOwner"] ),
         "TypeDef": ( traits: ["NameOwner"] ),
+        "ImplItem": (),
         "Name": (),
         "NameRef": (),
     },