diff --git a/openssl-sys/src/lib.rs b/openssl-sys/src/lib.rs
index 8550ce33100f75d9cde7090cba3eb22a3760e336..2a99d7108f9394f17f74be3a323f84830e50fd4d 100644
--- a/openssl-sys/src/lib.rs
+++ b/openssl-sys/src/lib.rs
@@ -39,7 +39,6 @@ pub type X509_NAME_ENTRY = c_void;
 pub type X509_REQ = c_void;
 pub type X509_STORE_CTX = c_void;
 
-#[allow(missing_copy_implementations)]
 #[repr(C)]
 pub struct EVP_MD_CTX {
     digest: *mut EVP_MD,
@@ -50,7 +49,8 @@ pub struct EVP_MD_CTX {
     update: *mut c_void
 }
 
-#[allow(missing_copy_implementations)]
+impl Copy for EVP_MD_CTX {}
+
 #[repr(C)]
 pub struct HMAC_CTX {
     md: *mut EVP_MD,
@@ -61,7 +61,8 @@ pub struct HMAC_CTX {
     key: [c_uchar, ..128]
 }
 
-#[allow(missing_copy_implementations)]
+impl Copy for HMAC_CTX {}
+
 #[repr(C)]
 pub struct X509V3_CTX {
     flags: c_int,
@@ -75,7 +76,8 @@ pub struct X509V3_CTX {
     // Maybe more here
 }
 
-#[allow(missing_copy_implementations)]
+impl Copy for X509V3_CTX {}
+
 #[repr(C)]
 pub struct BIGNUM {
     pub d: *mut c_void,
@@ -85,6 +87,8 @@ pub struct BIGNUM {
     pub flags: c_int,
 }
 
+impl Copy for BIGNUM {}
+
 pub type CRYPTO_EX_new = extern "C" fn(parent: *mut c_void, ptr: *mut c_void,
                                        ad: *const CRYPTO_EX_DATA, idx: c_int,
                                        argl: c_long, argp: *const c_void) -> c_int;
diff --git a/src/x509/mod.rs b/src/x509/mod.rs
index 47294c3d10f51db0ddae2ed00bc8baae0f339942..8baafe410b79e65b248edfe8aca463a163831350 100644
--- a/src/x509/mod.rs
+++ b/src/x509/mod.rs
@@ -362,7 +362,7 @@ impl<'ctx> X509<'ctx> {
     }
 
     /// Reads certificate from PEM, takes ownership of handle
-    pub fn from_pem(reader: &mut Reader) -> Result<X509<'ctx>, SslError> {
+    pub fn from_pem<R>(reader: &mut R) -> Result<X509<'ctx>, SslError> where R: Reader {
         let mut mem_bio = try!(MemBio::new());
         let buf = try!(reader.read_to_end().map_err(StreamError));
         try!(mem_bio.write(buf.as_slice()).map_err(StreamError));
@@ -404,7 +404,7 @@ impl<'ctx> X509<'ctx> {
     }
 
     /// Writes certificate as PEM
-    pub fn write_pem(&self, writer: &mut Writer) -> Result<(), SslError> {
+    pub fn write_pem<W>(&self, writer: &mut W) -> Result<(), SslError> where W: Writer{
         let mut mem_bio = try!(MemBio::new());
         unsafe {
             try_ssl!(ffi::PEM_write_bio_X509(mem_bio.get_handle(),