diff --git a/src/header/common/cache_control.rs b/src/header/common/cache_control.rs
index adbcaf18b0..c9a19e17b9 100644
--- a/src/header/common/cache_control.rs
+++ b/src/header/common/cache_control.rs
@@ -66,6 +66,12 @@ impl Header for CacheControl {
 
 impl HeaderFormat for CacheControl {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for CacheControl {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt_comma_delimited(f, &self[..])
     }
 }
diff --git a/src/header/common/expect.rs b/src/header/common/expect.rs
index f380e5271a..2aa9ad5fb7 100644
--- a/src/header/common/expect.rs
+++ b/src/header/common/expect.rs
@@ -57,6 +57,12 @@ impl Header for Expect {
 
 impl HeaderFormat for Expect {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for Expect {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.write_str("100-continue")
     }
 }
diff --git a/src/header/common/origin.rs b/src/header/common/origin.rs
index 4f2d1ba17d..3fbbe05cfa 100644
--- a/src/header/common/origin.rs
+++ b/src/header/common/origin.rs
@@ -84,6 +84,12 @@ impl FromStr for Origin {
 
 impl HeaderFormat for Origin {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for Origin {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}://{}", self.scheme, self.host)
     }
 }
diff --git a/src/header/common/pragma.rs b/src/header/common/pragma.rs
index 39dee7e8c5..5acf4b926e 100644
--- a/src/header/common/pragma.rs
+++ b/src/header/common/pragma.rs
@@ -56,6 +56,12 @@ impl Header for Pragma {
 
 impl HeaderFormat for Pragma {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for Pragma {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.write_str(match *self {
             Pragma::NoCache => "no-cache",
             Pragma::Ext(ref string) => &string[..],
diff --git a/src/header/common/prefer.rs b/src/header/common/prefer.rs
index 71490da1be..a72effa09b 100644
--- a/src/header/common/prefer.rs
+++ b/src/header/common/prefer.rs
@@ -68,6 +68,12 @@ impl Header for Prefer {
 
 impl HeaderFormat for Prefer {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for Prefer {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt_comma_delimited(f, &self[..])
     }
 }
diff --git a/src/header/common/preference_applied.rs b/src/header/common/preference_applied.rs
index fd1bc36fd0..a6b789fa3d 100644
--- a/src/header/common/preference_applied.rs
+++ b/src/header/common/preference_applied.rs
@@ -65,6 +65,13 @@ impl Header for PreferenceApplied {
 
 impl HeaderFormat for PreferenceApplied {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for PreferenceApplied {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        //TODO: format this without allocating a Vec and cloning contents
         let preferences: Vec<_> = self.0.iter().map(|pref| match pref {
             // The spec ignores parameters in `Preferences-Applied`
             &Preference::Extension(ref name, ref value, _) => Preference::Extension(
diff --git a/src/header/common/referrer_policy.rs b/src/header/common/referrer_policy.rs
index 08fd85c9b3..1091a219b0 100644
--- a/src/header/common/referrer_policy.rs
+++ b/src/header/common/referrer_policy.rs
@@ -82,6 +82,12 @@ impl Header for ReferrerPolicy {
 
 impl HeaderFormat for ReferrerPolicy {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for ReferrerPolicy {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         use self::ReferrerPolicy::*;
         f.write_str(match *self {
             NoReferrer => "no-referrer",
diff --git a/src/header/common/strict_transport_security.rs b/src/header/common/strict_transport_security.rs
index 5497830765..e80503a3ce 100644
--- a/src/header/common/strict_transport_security.rs
+++ b/src/header/common/strict_transport_security.rs
@@ -131,6 +131,12 @@ impl Header for StrictTransportSecurity {
 
 impl HeaderFormat for StrictTransportSecurity {
     fn fmt_header(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self, f)
+    }
+}
+
+impl fmt::Display for StrictTransportSecurity {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         if self.include_subdomains {
             write!(f, "max-age={}; includeSubdomains", self.max_age)
         } else {