diff --git a/serde2/serde2_macros/src/lib.rs b/serde2/serde2_macros/src/lib.rs
index 831ea512..fe5fd91b 100644
--- a/serde2/serde2_macros/src/lib.rs
+++ b/serde2/serde2_macros/src/lib.rs
@@ -9,7 +9,6 @@ use syntax::ast::{
     Item,
     Expr,
     MutMutable,
-    //LitNil,
 };
 use syntax::ast;
 use syntax::codemap::{Span, respan};
@@ -34,7 +33,6 @@ use syntax::ext::deriving::generic::ty::{
     LifetimeBounds,
     Ty,
     Path,
-    //Tuple,
     borrowed_explicit_self,
 };
 use syntax::parse::token;
diff --git a/serde2/src/ser.rs b/serde2/src/ser.rs
index aa4d3e6c..4c4ed8be 100644
--- a/serde2/src/ser.rs
+++ b/serde2/src/ser.rs
@@ -30,20 +30,6 @@ pub trait Visitor {
     type Value;
     type Error;
 
-    fn visit_unit(&mut self) -> Result<Self::Value, Self::Error>;
-
-    #[inline]
-    fn visit_named_unit(&mut self, _name: &str) -> Result<Self::Value, Self::Error> {
-        self.visit_unit()
-    }
-
-    #[inline]
-    fn visit_enum_unit(&mut self,
-                       _name: &str,
-                       _variant: &str) -> Result<Self::Value, Self::Error> {
-        self.visit_unit()
-    }
-
     fn visit_bool(&mut self, v: bool) -> Result<Self::Value, Self::Error>;
 
     #[inline]
@@ -109,6 +95,20 @@ pub trait Visitor {
 
     fn visit_str(&mut self, value: &str) -> Result<Self::Value, Self::Error>;
 
+    fn visit_unit(&mut self) -> Result<Self::Value, Self::Error>;
+
+    #[inline]
+    fn visit_named_unit(&mut self, _name: &str) -> Result<Self::Value, Self::Error> {
+        self.visit_unit()
+    }
+
+    #[inline]
+    fn visit_enum_unit(&mut self,
+                       _name: &str,
+                       _variant: &str) -> Result<Self::Value, Self::Error> {
+        self.visit_unit()
+    }
+
     fn visit_none(&mut self) -> Result<Self::Value, Self::Error>;
 
     fn visit_some<V>(&mut self, value: V) -> Result<Self::Value, Self::Error>
diff --git a/serde_macros/src/lib.rs b/serde_macros/src/lib.rs
index 563f94a4..5ec348eb 100644
--- a/serde_macros/src/lib.rs
+++ b/serde_macros/src/lib.rs
@@ -1,7 +1,7 @@
 #![crate_name = "serde_macros"]
 #![crate_type = "dylib"]
 
-#![feature(plugin_registrar, quote, unboxed_closures, rustc_private)]
+#![feature(core, plugin_registrar, quote, unboxed_closures, rustc_private)]
 
 extern crate syntax;
 extern crate rustc;
@@ -143,7 +143,7 @@ fn serialize_substructure(cx: &ExtCtxt,
                         let name = match (serial_name, name) {
                             (Some(serial), _) => serial.clone(),
                             (None, Some(id)) => token::get_ident(id),
-                            (None, None) => token::intern_and_get_ident(&format!("_field{}", i)),
+                            (None, None) => token::intern_and_get_ident(&format!("_field{}", i)[]),
                         };
 
                         let name = cx.expr_str(span, name);
@@ -261,7 +261,7 @@ fn deserialize_substructure(cx: &mut ExtCtxt,
                 cx,
                 span,
                 substr.type_ident,
-                &definition.fields,
+                &definition.fields[],
                 fields,
                 deserializer.clone(),
                 token)
@@ -271,8 +271,8 @@ fn deserialize_substructure(cx: &mut ExtCtxt,
                 cx,
                 span,
                 substr.type_ident,
-                &definition.variants,
-                &fields,
+                &definition.variants[],
+                &fields[],
                 deserializer,
                 token)
         }
@@ -300,7 +300,7 @@ fn deserialize_struct(
     let field_idents: Vec<ast::Ident> = fields.iter()
         .enumerate()
         .map(|(idx, _)| {
-            cx.ident_of(&format!("field{}", idx))
+            cx.ident_of(&format!("field{}", idx)[])
         })
         .collect();
 
@@ -415,7 +415,7 @@ fn deserialize_enum(
                 cx,
                 span,
                 path,
-                &serial_names,
+                &serial_names[],
                 parts,
                 |&: cx, _, _| {
                     quote_expr!(cx, try!($deserializer.expect_enum_elt()))
@@ -461,7 +461,7 @@ fn deserialize_static_fields<F>(
                     getarg(
                         cx,
                         span,
-                        token::intern_and_get_ident(&format!("_field{}", i))
+                        token::intern_and_get_ident(&format!("_field{}", i)[])
                     )
                 }).collect();
 
@@ -488,7 +488,7 @@ fn deserialize_static_fields<F>(
     }
 }
 
-fn find_serial_name<'a, I>(iterator: I) -> Option<token::InternedString> where
+fn find_serial_name<'a, I>(mut iterator: I) -> Option<token::InternedString> where
     I: Iterator<Item=&'a Attribute>
 {
     for at in iterator {