diff --git a/src/io/mod.rs b/src/io/mod.rs
index bd2313f8..2e53af42 100644
--- a/src/io/mod.rs
+++ b/src/io/mod.rs
@@ -3,6 +3,7 @@ pub use priv_io::Stream;
 
 use std::error::Error;
 use std::io::prelude::*;
+use std::fmt;
 
 #[cfg(feature = "openssl")]
 mod openssl;
@@ -25,10 +26,7 @@ pub trait StreamWrapper: Read+Write+Send {
 ///
 /// If the `security-framework` Cargo feature is enabled, this trait will be
 /// implemented for `security_framework::secure_transport::ClientBuilder`.
-///
-/// It is also implemented for `Fn(&str, Stream) -> Result<Box<StreamWrapper>,
-/// Box<Error + Sync + Send>` closures.
-pub trait NegotiateSsl {
+pub trait NegotiateSsl: fmt::Debug {
     /// Negotiates an SSL session, returning a wrapper around the provided
     /// stream.
     ///
@@ -39,14 +37,3 @@ pub trait NegotiateSsl {
                      stream: Stream)
                      -> Result<Box<StreamWrapper>, Box<Error + Sync + Send>>;
 }
-
-impl<F> NegotiateSsl for F
-    where F: Fn(&str, Stream) -> Result<Box<StreamWrapper>, Box<Error + Sync + Send>>
-{
-    fn negotiate_ssl(&self,
-                     host: &str,
-                     stream: Stream)
-                     -> Result<Box<StreamWrapper>, Box<Error + Sync + Send>> {
-        (*self)(host, stream)
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index f777408f..7374bff8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -352,6 +352,7 @@ impl IsolationLevel {
 }
 
 /// Specifies the SSL support requested for a new connection.
+#[derive(Debug)]
 pub enum SslMode<'a> {
     /// The connection will not use SSL.
     None,
@@ -361,16 +362,6 @@ pub enum SslMode<'a> {
     Require(&'a NegotiateSsl),
 }
 
-impl<'a> fmt::Debug for SslMode<'a> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            SslMode::None => fmt.write_str("None"),
-            SslMode::Prefer(..) => fmt.write_str("Prefer"),
-            SslMode::Require(..) => fmt.write_str("Require"),
-        }
-    }
-}
-
 #[derive(Clone)]
 struct CachedStatement {
     name: String,