diff --git a/macros/src/pre_expand.rs b/macros/src/pre_expand.rs
index 75abb47a..60fbffd8 100644
--- a/macros/src/pre_expand.rs
+++ b/macros/src/pre_expand.rs
@@ -26,8 +26,10 @@ pub fn pre_expand(from: &Path, to: &Path) {
     write_header(&from, &source, &mut file_to);
 
     let sess = parse::ParseSess::new();
+    let mut feature_gated_cfgs = Vec::new();
     let mut cx = ext::base::ExtCtxt::new(&sess, vec![],
-        ext::expand::ExpansionConfig::default("".to_owned()));
+        ext::expand::ExpansionConfig::default("".to_owned()),
+        &mut feature_gated_cfgs);
 
     let from = from.to_string_lossy().into_owned();
     let tts = parse::parse_tts_from_source_str(from, source, vec![], &sess);
diff --git a/tests/tokenizer.rs b/tests/tokenizer.rs
index ccac7469..59236fd1 100644
--- a/tests/tokenizer.rs
+++ b/tests/tokenizer.rs
@@ -144,7 +144,7 @@ fn tokenize(input: Vec<StrTendril>, opts: TokenizerOpts) -> Vec<Token> {
     tok.unwrap().get_tokens()
 }
 
-trait JsonExt {
+trait JsonExt: Sized {
     fn get_str(&self) -> String;
     fn get_tendril(&self) -> StrTendril;
     fn get_nullable_tendril(&self) -> Option<StrTendril>;