diff --git a/src/common/cache_control.rs b/src/common/cache_control.rs
index 1c811484..d5661ebd 100644
--- a/src/common/cache_control.rs
+++ b/src/common/cache_control.rs
@@ -305,7 +305,7 @@ impl FromIterator<KnownDirective> for FromIter {
 
 struct Fmt<'a>(&'a CacheControl);
 
-impl<'a> fmt::Display for Fmt<'a> {
+impl fmt::Display for Fmt<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let if_flag = |f: Flags, dir: Directive| {
             if self.0.flags.contains(f) {
diff --git a/src/common/connection.rs b/src/common/connection.rs
index b7acd251..eed92384 100644
--- a/src/common/connection.rs
+++ b/src/common/connection.rs
@@ -108,21 +108,21 @@ mod sealed {
     }
     pub trait Sealed {}
 
-    impl<'a> AsConnectionOption for &'a str {
+    impl AsConnectionOption for &str {
         fn as_connection_option(&self) -> &str {
             self
         }
     }
 
-    impl<'a> Sealed for &'a str {}
+    impl Sealed for &str {}
 
-    impl<'a> AsConnectionOption for &'a HeaderName {
+    impl AsConnectionOption for &HeaderName {
         fn as_connection_option(&self) -> &str {
             self.as_ref()
         }
     }
 
-    impl<'a> Sealed for &'a HeaderName {}
+    impl Sealed for &HeaderName {}
 
     impl AsConnectionOption for HeaderName {
         fn as_connection_option(&self) -> &str {
diff --git a/src/common/content_encoding.rs b/src/common/content_encoding.rs
index c218ea96..ff2f204e 100644
--- a/src/common/content_encoding.rs
+++ b/src/common/content_encoding.rs
@@ -89,9 +89,9 @@ mod sealed {
         fn as_coding(&self) -> &str;
     }
 
-    impl<'a> AsCoding for &'a str {}
+    impl AsCoding for &str {}
 
-    impl<'a> Sealed for &'a str {
+    impl Sealed for &str {
         fn as_coding(&self) -> &str {
             self
         }
diff --git a/src/common/content_range.rs b/src/common/content_range.rs
index dd5da002..08de5ccf 100644
--- a/src/common/content_range.rs
+++ b/src/common/content_range.rs
@@ -146,7 +146,7 @@ impl Header for ContentRange {
     fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {
         struct Adapter<'a>(&'a ContentRange);
 
-        impl<'a> fmt::Display for Adapter<'a> {
+        impl fmt::Display for Adapter<'_> {
             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 f.write_str("bytes ")?;
 
diff --git a/src/common/strict_transport_security.rs b/src/common/strict_transport_security.rs
index e0381432..5122e971 100644
--- a/src/common/strict_transport_security.rs
+++ b/src/common/strict_transport_security.rs
@@ -147,7 +147,7 @@ impl Header for StrictTransportSecurity {
     fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {
         struct Adapter<'a>(&'a StrictTransportSecurity);
 
-        impl<'a> fmt::Display for Adapter<'a> {
+        impl fmt::Display for Adapter<'_> {
             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 if self.0.include_subdomains {
                     write!(f, "max-age={}; includeSubdomains", self.0.max_age)
diff --git a/src/map_ext.rs b/src/map_ext.rs
index c79e59e0..f92a3697 100644
--- a/src/map_ext.rs
+++ b/src/map_ext.rs
@@ -61,7 +61,7 @@ enum State<'a> {
     Tmp,
 }
 
-impl<'a> Extend<HeaderValue> for ToValues<'a> {
+impl Extend<HeaderValue> for ToValues<'_> {
     fn extend<T: IntoIterator<Item = HeaderValue>>(&mut self, iter: T) {
         for value in iter {
             let entry = match ::std::mem::replace(&mut self.state, State::Tmp) {