syntax: Add ToTokens for Option<T>

Author: bgamari

src/libsyntax/ext/quote.rs

@@ -67,6 +67,15 @@ pub mod rt {
         }
     }
 
+    impl<T: ToTokens> ToTokens for Option<T> {
+        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
+            match self {
+                &Some(ref t) => t.to_tokens(cx),
+                &None => Vec::new(),
+            }
+        }
+    }
+
     /* Should be (when bugs in default methods are fixed):
 
     trait ToSource : ToTokens {