diff --git a/src/libhttp/headers/connection.rs b/src/libhttp/headers/connection.rs
index 312aace..04acd6f 100644
--- a/src/libhttp/headers/connection.rs
+++ b/src/libhttp/headers/connection.rs
@@ -23,7 +23,7 @@ impl ToStr for Connection {
     }
 }
 
-impl super::CommaListHeaderConvertible for Connection;
+impl super::CommaListHeaderConvertible for Connection {}
 
 impl super::HeaderConvertible for Connection {
     fn from_stream<T: Reader>(reader: &mut super::HeaderValueByteIterator<T>)
diff --git a/src/libhttp/headers/mod.rs b/src/libhttp/headers/mod.rs
index 1c7bc7f..e81a915 100644
--- a/src/libhttp/headers/mod.rs
+++ b/src/libhttp/headers/mod.rs
@@ -612,7 +612,7 @@ impl HeaderConvertible for Url {
     }
 }
 
-impl CommaListHeaderConvertible for Method;
+impl CommaListHeaderConvertible for Method {}
 
 impl HeaderConvertible for Method {
     fn from_stream<T: Reader>(reader: &mut HeaderValueByteIterator<T>) -> Option<Method> {
diff --git a/src/libhttp/headers/transfer_encoding.rs b/src/libhttp/headers/transfer_encoding.rs
index 2aa4e0c..619b69b 100644
--- a/src/libhttp/headers/transfer_encoding.rs
+++ b/src/libhttp/headers/transfer_encoding.rs
@@ -16,7 +16,7 @@ pub enum TransferCoding {
     TransferExtension(~str, ~[(~str, ~str)]),
 }
 
-impl super::CommaListHeaderConvertible for TransferCoding;
+impl super::CommaListHeaderConvertible for TransferCoding {}
 
 impl super::HeaderConvertible for TransferCoding {
     fn from_stream<T: Reader>(reader: &mut super::HeaderValueByteIterator<T>)