more functional

src/mimeparser.rs

@@ -910,18 +910,18 @@ impl MimeMessage {
                 .to_ascii_lowercase()
                 .contains("daemon")
             && self.failure_report.is_none()
-        {
-            for line in self
-                .parts
-                .iter()
-                .filter_map(|p| p.msg_raw.as_ref())
-                .flat_map(|p| p.lines())
         {
             lazy_static! {
                 static ref RE: regex::Regex = regex::Regex::new(r"Message-ID:(.*)").unwrap();
             }
-                if let Some(c) = RE.captures(line) {
-                    if let Ok(original_message_id) = parse_message_id(&c[1]) {
+            for captures in self
+                .parts
+                .iter()
+                .filter_map(|part| part.msg_raw.as_ref())
+                .flat_map(|part| part.lines())
+                .filter_map(|line| RE.captures(line))
+            {
+                if let Ok(original_message_id) = parse_message_id(&captures[1]) {
                     if let Ok(Some(_)) =
                         message::rfc724_mid_exists(context, &original_message_id).await
                     {
@@ -933,7 +933,6 @@ impl MimeMessage {
                 }
             }
         }
-        }
         None // Always return None, we just return anything so that we can use the '?' operator.
     }