From a0c95f748ed39467100ddda24698df8629b95369 Mon Sep 17 00:00:00 2001
From: Alexis Mousset <alexis.mousset@normation.com>
Date: Tue, 17 Apr 2018 00:21:43 +0200
Subject: [PATCH] feat(transport): Use an associated type for result type of
 EmailTransport

---
 lettre/src/file/mod.rs     | 4 +++-
 lettre/src/lib.rs          | 7 +++++--
 lettre/src/sendmail/mod.rs | 4 +++-
 lettre/src/smtp/mod.rs     | 4 +++-
 lettre/src/stub/mod.rs     | 4 +++-
 5 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/lettre/src/file/mod.rs b/lettre/src/file/mod.rs
index fcb80f6..db94f3a 100644
--- a/lettre/src/file/mod.rs
+++ b/lettre/src/file/mod.rs
@@ -31,7 +31,9 @@ impl FileEmailTransport {
     }
 }
 
-impl<'a, T: Read + 'a> EmailTransport<'a, T, FileResult> for FileEmailTransport {
+impl<'a, T: Read + 'a> EmailTransport<'a, T> for FileEmailTransport {
+    type Result = FileResult;
+
     fn send<U: SendableEmail<'a, T> + 'a>(&mut self, email: &'a U) -> FileResult {
         let mut file = self.path.clone();
         file.push(format!("{}.txt", email.message_id()));
diff --git a/lettre/src/lib.rs b/lettre/src/lib.rs
index 47b4028..d688a76 100644
--- a/lettre/src/lib.rs
+++ b/lettre/src/lib.rs
@@ -212,9 +212,12 @@ pub trait SendableEmail<'a, T: Read + 'a> {
 }
 
 /// Transport method for emails
-pub trait EmailTransport<'a, U: Read + 'a, V> {
+pub trait EmailTransport<'a, U: Read + 'a> {
+    /// Result type for the transport
+    type Result;
+
     /// Sends the email
-    fn send<T: SendableEmail<'a, U> + 'a>(&mut self, email: &'a T) -> V;
+    fn send<T: SendableEmail<'a, U> + 'a>(&mut self, email: &'a T) -> Self::Result;
 }
 
 /// Minimal email structure
diff --git a/lettre/src/sendmail/mod.rs b/lettre/src/sendmail/mod.rs
index a40d9d6..018b6bd 100644
--- a/lettre/src/sendmail/mod.rs
+++ b/lettre/src/sendmail/mod.rs
@@ -32,7 +32,9 @@ impl SendmailTransport {
     }
 }
 
-impl<'a, T: Read + 'a> EmailTransport<'a, T, SendmailResult> for SendmailTransport {
+impl<'a, T: Read + 'a> EmailTransport<'a, T> for SendmailTransport {
+    type Result = SendmailResult;
+
     fn send<U: SendableEmail<'a, T> + 'a>(&mut self, email: &'a U) -> SendmailResult {
         let envelope = email.envelope();
 
diff --git a/lettre/src/smtp/mod.rs b/lettre/src/smtp/mod.rs
index bec5480..4d7cba2 100644
--- a/lettre/src/smtp/mod.rs
+++ b/lettre/src/smtp/mod.rs
@@ -306,7 +306,9 @@ impl<'a> SmtpTransport {
     }
 }
 
-impl<'a, T: Read + 'a> EmailTransport<'a, T, SmtpResult> for SmtpTransport {
+impl<'a, T: Read + 'a> EmailTransport<'a, T> for SmtpTransport {
+    type Result = SmtpResult;
+
     /// Sends an email
     #[cfg_attr(feature = "cargo-clippy", allow(match_same_arms, cyclomatic_complexity))]
     fn send<U: SendableEmail<'a, T> + 'a>(&mut self, email: &'a U) -> SmtpResult {
diff --git a/lettre/src/stub/mod.rs b/lettre/src/stub/mod.rs
index 2e6247c..efa7034 100644
--- a/lettre/src/stub/mod.rs
+++ b/lettre/src/stub/mod.rs
@@ -27,7 +27,9 @@ impl StubEmailTransport {
 /// SMTP result type
 pub type StubResult = Result<(), ()>;
 
-impl<'a, T: Read + 'a> EmailTransport<'a, T, StubResult> for StubEmailTransport {
+impl<'a, T: Read + 'a> EmailTransport<'a, T> for StubEmailTransport {
+    type Result = StubResult;
+
     fn send<U: SendableEmail<'a, T>>(&mut self, email: &'a U) -> StubResult {
         let envelope = email.envelope();
         info!(