More clever highlighting, incl draft for structs

crates/ra_syntax/src/syntax_node.rs

@@ -523,10 +523,6 @@ impl<'a> SyntaxElement<'a> {
         }
     }
 
-    pub fn as_ast_node<T: AstNode>(&self) -> Option<&T> {
-        self.as_node().and_then(|x| <T as AstNode>::cast(x))
-    }
-
     pub fn as_token(&self) -> Option<SyntaxToken<'a>> {
         match self {
             SyntaxElement::Node(_) => None,