Simplify lifetime bounds

A missing lifetime in the GetHeader trait was inferred by lifetime elision rules
to be shorter than necessary, leading to awkward lifetime constraints being
propagated throughout many functions that didnt need them.

Author: sftse

src/core/address.rs

@@ -73,7 +73,7 @@ impl<'x> Address<'x> {
     }
 
     /// Returns an iterator over the addresses in the list, or the addresses in the groups.
-    pub fn iter<'y: 'x>(&'y self) -> Box<dyn DoubleEndedIterator<Item = &Addr<'x>> + 'x> {
+    pub fn iter(&self) -> Box<dyn DoubleEndedIterator<Item = &Addr<'x>> + '_> {
         match self {
             Address::List(list) => Box::new(list.iter()),
             Address::Group(group) => {

src/core/header.rs

@@ -374,7 +374,7 @@ impl<'x> HeaderName<'x> {
         }
     }
 
-    pub fn as_str<'y: 'x>(&'y self) -> &'x str {
+    pub fn as_str(&self) -> &str {
         match self {
             HeaderName::Other(other) => other.as_ref(),
             _ => self.as_static_str(),
@@ -921,14 +921,14 @@ impl<'x> Host<'x> {
 }
 
 impl<'x> GetHeader<'x> for Vec<Header<'x>> {
-    fn header_value(&self, name: &HeaderName) -> Option<&HeaderValue<'x>> {
+    fn header_value(&self, name: &HeaderName<'_>) -> Option<&HeaderValue<'x>> {
         self.iter()
             .rev()
             .find(|header| &header.name == name)
             .map(|header| &header.value)
     }
 
-    fn header(&self, name: impl Into<HeaderName<'x>>) -> Option<&Header> {
+    fn header(&self, name: impl Into<HeaderName<'x>>) -> Option<&Header<'x>> {
         let name = name.into();
         self.iter().rev().find(|header| header.name == name)
     }

src/core/message.rs

@@ -90,8 +90,8 @@ impl<'x> Message<'x> {
     }
 
     /// Returns an iterator over the matching RFC headers of this message.
-    pub fn header_values<'y: 'x>(
-        &'y self,
+    pub fn header_values(
+        &self,
         name: impl Into<HeaderName<'x>>,
     ) -> impl Iterator<Item = &HeaderValue<'x>> {
         let name = name.into();
@@ -124,15 +124,15 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the BCC header field
-    pub fn bcc<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn bcc(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::Bcc)
             .and_then(|a| a.as_address())
     }
 
     /// Returns the CC header field
-    pub fn cc<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn cc(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::Cc)
@@ -156,7 +156,7 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the From header field
-    pub fn from<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn from(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::From)
@@ -268,23 +268,23 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the Reply-To header field
-    pub fn reply_to<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn reply_to(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ReplyTo)
             .and_then(|a| a.as_address())
     }
 
     /// Returns the Resent-BCC header field
-    pub fn resent_bcc<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn resent_bcc(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ResentBcc)
             .and_then(|a| a.as_address())
     }
 
     /// Returns the Resent-CC header field
-    pub fn resent_cc<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn resent_cc(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ResentTo)
@@ -300,7 +300,7 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the Resent-From header field
-    pub fn resent_from<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn resent_from(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ResentFrom)
@@ -316,15 +316,15 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the Sender header field
-    pub fn resent_sender<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn resent_sender(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ResentSender)
             .and_then(|a| a.as_address())
     }
 
     /// Returns the Resent-To header field
-    pub fn resent_to<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn resent_to(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::ResentTo)
@@ -353,7 +353,7 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the Sender header field
-    pub fn sender<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn sender(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::Sender)
@@ -375,7 +375,7 @@ impl<'x> Message<'x> {
     }
 
     /// Returns the To header field
-    pub fn to<'y: 'x>(&'y self) -> Option<&Address<'x>> {
+    pub fn to(&self) -> Option<&Address<'x>> {
         self.parts[0]
             .headers
             .header_value(&HeaderName::To)

src/lib.rs

@@ -649,8 +649,8 @@ pub trait MimeHeaders<'x> {
 }
 
 pub trait GetHeader<'x> {
-    fn header_value(&self, name: &HeaderName) -> Option<&HeaderValue>;
-    fn header(&self, name: impl Into<HeaderName<'x>>) -> Option<&Header>;
+    fn header_value(&self, name: &HeaderName<'_>) -> Option<&HeaderValue<'x>>;
+    fn header(&self, name: impl Into<HeaderName<'x>>) -> Option<&Header<'x>>;
 }
 
 #[doc(hidden)]