melib: fix clippy lints

17 files changed, 252 insertions, 96 deletions

diff --git a/melib/src/addressbook.rs b/melib/src/addressbook.rs
index 36cbfaf8..276c0ae5 100644
--- a/melib/src/addressbook.rs
+++ b/melib/src/addressbook.rs
@@ -56,7 +56,7 @@ impl From<String> for CardId {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
 pub struct AddressBook {
     display_name: String,
     created: UnixTimestamp,
@@ -64,7 +64,7 @@ pub struct AddressBook {
     pub cards: HashMap<CardId, Card>,
 }
 
-#[derive(Debug, Clone, PartialEq, Deserialize, Serialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
 pub struct Card {
     id: CardId,
     title: String,
diff --git a/melib/src/backends.rs b/melib/src/backends.rs
index 088a34ee..b174abbd 100644
--- a/melib/src/backends.rs
+++ b/melib/src/backends.rs
@@ -398,49 +398,37 @@ pub trait MailBackend: ::std::fmt::Debug + Send + Sync {
 
     fn create_mailbox(
         &mut self,
-        _path: String,
-    ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)> {
-        Err(MeliError::new("Creating mailbox is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        path: String,
+    ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)>;
 
     fn delete_mailbox(
         &mut self,
-        _mailbox_hash: MailboxHash,
-    ) -> ResultFuture<HashMap<MailboxHash, Mailbox>> {
-        Err(MeliError::new("Deleting mailbox is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        mailbox_hash: MailboxHash,
+    ) -> ResultFuture<HashMap<MailboxHash, Mailbox>>;
 
     fn set_mailbox_subscription(
         &mut self,
-        _mailbox_hash: MailboxHash,
-        _val: bool,
-    ) -> ResultFuture<()> {
-        Err(MeliError::new("Setting mailbox subscription is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        mailbox_hash: MailboxHash,
+        val: bool,
+    ) -> ResultFuture<()>;
 
     fn rename_mailbox(
         &mut self,
-        _mailbox_hash: MailboxHash,
-        _new_path: String,
-    ) -> ResultFuture<Mailbox> {
-        Err(MeliError::new("Renaming mailbox is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        mailbox_hash: MailboxHash,
+        new_path: String,
+    ) -> ResultFuture<Mailbox>;
 
     fn set_mailbox_permissions(
         &mut self,
-        _mailbox_hash: MailboxHash,
-        _val: MailboxPermissions,
-    ) -> ResultFuture<()> {
-        Err(MeliError::new("Setting mailbox permissions is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        mailbox_hash: MailboxHash,
+        val: MailboxPermissions,
+    ) -> ResultFuture<()>;
 
     fn search(
         &self,
-        _query: crate::search::Query,
-        _mailbox_hash: Option<MailboxHash>,
-    ) -> ResultFuture<SmallVec<[EnvelopeHash; 512]>> {
-        Err(MeliError::new("Search is currently unimplemented.").set_kind(ErrorKind::NotImplemented))
-    }
+        query: crate::search::Query,
+        mailbox_hash: Option<MailboxHash>,
+    ) -> ResultFuture<SmallVec<[EnvelopeHash; 512]>>;
 
     fn submit(
         &self,
@@ -448,7 +436,8 @@ pub trait MailBackend: ::std::fmt::Debug + Send + Sync {
         _mailbox_hash: Option<MailboxHash>,
         _flags: Option<Flag>,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Not supported in this backend.").set_kind(ErrorKind::NotSupported))
+        Err(MeliError::new("Submission not supported in this backend.")
+            .set_kind(ErrorKind::NotSupported))
     }
 }
 
@@ -634,7 +623,7 @@ impl std::fmt::Display for MailboxPermissions {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct EnvelopeHashBatch {
     pub first: EnvelopeHash,
     pub rest: SmallVec<[EnvelopeHash; 64]>,
diff --git a/melib/src/backends/imap/managesieve.rs b/melib/src/backends/imap/managesieve.rs
index 67c036c6..d60f2238 100644
--- a/melib/src/backends/imap/managesieve.rs
+++ b/melib/src/backends/imap/managesieve.rs
@@ -349,10 +349,8 @@ impl ManageSieveConnection {
             ManageSieveResponse::Ok { .. } => Ok(()),
             ManageSieveResponse::NoBye { code, message } => Err(format!(
                 "Could not upload script: {} {}",
-                code.map(|b| String::from_utf8_lossy(b)).unwrap_or_default(),
-                message
-                    .map(|b| String::from_utf8_lossy(b))
-                    .unwrap_or_default()
+                code.map(String::from_utf8_lossy).unwrap_or_default(),
+                message.map(String::from_utf8_lossy).unwrap_or_default()
             )
             .into()),
         }
@@ -386,10 +384,8 @@ impl ManageSieveConnection {
             ManageSieveResponse::Ok { .. } => Ok(()),
             ManageSieveResponse::NoBye { code, message } => Err(format!(
                 "Checkscript reply: {} {}",
-                code.map(|b| String::from_utf8_lossy(b)).unwrap_or_default(),
-                message
-                    .map(|b| String::from_utf8_lossy(b))
-                    .unwrap_or_default()
+                code.map(String::from_utf8_lossy).unwrap_or_default(),
+                message.map(String::from_utf8_lossy).unwrap_or_default()
             )
             .into()),
         }
@@ -409,10 +405,8 @@ impl ManageSieveConnection {
             ManageSieveResponse::Ok { .. } => Ok(()),
             ManageSieveResponse::NoBye { code, message } => Err(format!(
                 "Could not set active script: {} {}",
-                code.map(|b| String::from_utf8_lossy(b)).unwrap_or_default(),
-                message
-                    .map(|b| String::from_utf8_lossy(b))
-                    .unwrap_or_default()
+                code.map(String::from_utf8_lossy).unwrap_or_default(),
+                message.map(String::from_utf8_lossy).unwrap_or_default()
             )
             .into()),
         }
@@ -432,10 +426,8 @@ impl ManageSieveConnection {
         {
             return Err(format!(
                 "Could not set active script: {} {}",
-                code.map(|b| String::from_utf8_lossy(b)).unwrap_or_default(),
-                message
-                    .map(|b| String::from_utf8_lossy(b))
-                    .unwrap_or_default()
+                code.map(String::from_utf8_lossy).unwrap_or_default(),
+                message.map(String::from_utf8_lossy).unwrap_or_default()
             )
             .into());
         }
@@ -460,10 +452,8 @@ impl ManageSieveConnection {
             ManageSieveResponse::Ok { .. } => Ok(()),
             ManageSieveResponse::NoBye { code, message } => Err(format!(
                 "Could not delete script: {} {}",
-                code.map(|b| String::from_utf8_lossy(b)).unwrap_or_default(),
-                message
-                    .map(|b| String::from_utf8_lossy(b))
-                    .unwrap_or_default()
+                code.map(String::from_utf8_lossy).unwrap_or_default(),
+                message.map(String::from_utf8_lossy).unwrap_or_default()
             )
             .into()),
         }
diff --git a/melib/src/backends/jmap.rs b/melib/src/backends/jmap.rs
index 12fe8ffe..4b03e404 100644
--- a/melib/src/backends/jmap.rs
+++ b/melib/src/backends/jmap.rs
@@ -586,14 +586,18 @@ impl MailBackend for JmapType {
         _mailbox_hash: MailboxHash,
         _new_path: String,
     ) -> ResultFuture<Mailbox> {
-        Err(MeliError::new("Renaming mailbox is currently unimplemented for jmap backend."))
+        Err(MeliError::new(
+            "Renaming mailbox is currently unimplemented for jmap backend.",
+        ))
     }
 
     fn create_mailbox(
         &mut self,
         _path: String,
     ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)> {
-        Err(MeliError::new("Creating mailbox is currently unimplemented for jmap backend."))
+        Err(MeliError::new(
+            "Creating mailbox is currently unimplemented for jmap backend.",
+        ))
     }
 
     fn copy_messages(
@@ -860,7 +864,9 @@ impl MailBackend for JmapType {
         _env_hashes: EnvelopeHashBatch,
         _mailbox_hash: MailboxHash,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Deleting messages is currently unimplemented for jmap backend."))
+        Err(MeliError::new(
+            "Deleting messages is currently unimplemented for jmap backend.",
+        ))
     }
 }
 
diff --git a/melib/src/backends/maildir/backend.rs b/melib/src/backends/maildir/backend.rs
index 405a1dfb..55b6ca47 100644
--- a/melib/src/backends/maildir/backend.rs
+++ b/melib/src/backends/maildir/backend.rs
@@ -1047,7 +1047,9 @@ impl MailBackend for MaildirType {
         &mut self,
         _mailbox_hash: MailboxHash,
     ) -> ResultFuture<HashMap<MailboxHash, Mailbox>> {
-        Err(MeliError::new("Deleting messages is currently unimplemented for maildir backend."))
+        Err(MeliError::new(
+            "Deleting mailboxes is currently unimplemented for maildir backend.",
+        ))
     }
 
     fn set_mailbox_subscription(
@@ -1055,7 +1057,9 @@ impl MailBackend for MaildirType {
         _mailbox_hash: MailboxHash,
         _val: bool,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Mailbox description is currently unimplemented for maildir backend."))
+        Err(MeliError::new(
+            "Mailbox subscriptions are not possible for the maildir backend.",
+        ))
     }
 
     fn rename_mailbox(
@@ -1063,7 +1067,9 @@ impl MailBackend for MaildirType {
         _mailbox_hash: MailboxHash,
         _new_path: String,
     ) -> ResultFuture<Mailbox> {
-        Err(MeliError::new("Renaming mailbox is currently unimplemented for maildir backend."))
+        Err(MeliError::new(
+            "Renaming mailboxes is currently unimplemented for maildir backend.",
+        ))
     }
 
     fn set_mailbox_permissions(
@@ -1071,7 +1077,20 @@ impl MailBackend for MaildirType {
         _mailbox_hash: MailboxHash,
         _val: crate::backends::MailboxPermissions,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Setting mailbox permissions is currently unimplemented for maildir backend."))
+        Err(MeliError::new(
+            "Setting mailbox permissions is not possible for the maildir backend.",
+        ))
+    }
+
+    fn search(
+        &self,
+        _query: crate::search::Query,
+        _mailbox_hash: Option<MailboxHash>,
+    ) -> ResultFuture<SmallVec<[EnvelopeHash; 512]>> {
+        Err(
+            MeliError::new("Search is unimplemented for the maildir backend.")
+                .set_kind(ErrorKind::NotImplemented),
+        )
     }
 
     fn as_any(&self) -> &dyn Any {
diff --git a/melib/src/backends/mbox.rs b/melib/src/backends/mbox.rs
index bffbf025..9b08063b 100644
--- a/melib/src/backends/mbox.rs
+++ b/melib/src/backends/mbox.rs
@@ -126,13 +126,13 @@ use crate::collection::Collection;
 use crate::conf::AccountSettings;
 use crate::email::parser::BytesExt;
 use crate::email::*;
-use crate::error::{MeliError, Result};
+use crate::error::{ErrorKind, MeliError, Result};
 use crate::get_path_hash;
 use crate::shellexpand::ShellExpandTrait;
 use nom::bytes::complete::tag;
 use nom::character::complete::digit1;
 use nom::combinator::map_res;
-use nom::{self, error::Error as NomError, error::ErrorKind, IResult};
+use nom::{self, error::Error as NomError, error::ErrorKind as NomErrorKind, IResult};
 
 extern crate notify;
 use self::notify::{watcher, DebouncedEvent, RecursiveMode, Watcher};
@@ -494,7 +494,7 @@ impl MboxFormat {
                             debug!("Could not parse mail {:?}", err);
                             Err(nom::Err::Error(NomError {
                                 input,
-                                code: ErrorKind::Tag,
+                                code: NomErrorKind::Tag,
                             }))
                         }
                     }
@@ -541,7 +541,7 @@ impl MboxFormat {
                             debug!("Could not parse mail at {:?}", err);
                             Err(nom::Err::Error(NomError {
                                 input,
-                                code: ErrorKind::Tag,
+                                code: NomErrorKind::Tag,
                             }))
                         }
                     }
@@ -598,7 +598,7 @@ impl MboxFormat {
                             debug!("Could not parse mail {:?}", err);
                             Err(nom::Err::Error(NomError {
                                 input,
-                                code: ErrorKind::Tag,
+                                code: NomErrorKind::Tag,
                             }))
                         }
                     }
@@ -645,7 +645,7 @@ impl MboxFormat {
                             debug!("Could not parse mail {:?}", err);
                             Err(nom::Err::Error(NomError {
                                 input,
-                                code: ErrorKind::Tag,
+                                code: NomErrorKind::Tag,
                             }))
                         }
                     }
@@ -739,7 +739,7 @@ pub fn mbox_parse(
     if input.is_empty() {
         return Err(nom::Err::Error(NomError {
             input,
-            code: ErrorKind::Tag,
+            code: NomErrorKind::Tag,
         }));
     }
     let mut offset = 0;
@@ -963,7 +963,9 @@ impl MailBackend for MboxType {
     }
 
     fn refresh(&mut self, _mailbox_hash: MailboxHash) -> ResultFuture<()> {
-        Err(MeliError::new("Refreshing is currently unimplemented for mbox backend."))
+        Err(MeliError::new(
+            "Refreshing is currently unimplemented for mbox backend.",
+        ))
     }
 
     fn watch(&self) -> ResultFuture<()> {
@@ -1154,7 +1156,9 @@ impl MailBackend for MboxType {
         _destination_mailbox_hash: MailboxHash,
         _move_: bool,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Copying messages is currently unimplemented for mbox backend"))
+        Err(MeliError::new(
+            "Copying messages is currently unimplemented for mbox backend",
+        ))
     }
 
     fn set_flags(
@@ -1163,7 +1167,9 @@ impl MailBackend for MboxType {
         _mailbox_hash: MailboxHash,
         _flags: SmallVec<[(std::result::Result<Flag, String>, bool); 8]>,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Settings flags is currently unimplemented for mbox backend"))
+        Err(MeliError::new(
+            "Settings flags is currently unimplemented for mbox backend",
+        ))
     }
 
     fn delete_messages(
@@ -1171,7 +1177,9 @@ impl MailBackend for MboxType {
         _env_hashes: EnvelopeHashBatch,
         _mailbox_hash: MailboxHash,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Deleting messages is currently unimplemented for mbox backend"))
+        Err(MeliError::new(
+            "Deleting messages is currently unimplemented for mbox backend",
+        ))
     }
 
     fn save(
@@ -1180,7 +1188,9 @@ impl MailBackend for MboxType {
         _mailbox_hash: MailboxHash,
         _flags: Option<Flag>,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Saving messages is currently unimplemented for mbox backend"))
+        Err(MeliError::new(
+            "Saving messages is currently unimplemented for mbox backend",
+        ))
     }
 
     fn as_any(&self) -> &dyn Any {
@@ -1194,6 +1204,66 @@ impl MailBackend for MboxType {
     fn collection(&self) -> Collection {
         self.collection.clone()
     }
+
+    fn delete_mailbox(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+    ) -> ResultFuture<HashMap<MailboxHash, Mailbox>> {
+        Err(MeliError::new(
+            "Deleting mailboxes is currently unimplemented for mbox backend.",
+        ))
+    }
+
+    fn set_mailbox_subscription(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _val: bool,
+    ) -> ResultFuture<()> {
+        Err(MeliError::new(
+            "Mailbox subscriptions are not possible for the mbox backend.",
+        ))
+    }
+
+    fn rename_mailbox(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _new_path: String,
+    ) -> ResultFuture<Mailbox> {
+        Err(MeliError::new(
+            "Renaming mailboxes is currently unimplemented for mbox backend.",
+        ))
+    }
+
+    fn set_mailbox_permissions(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _val: crate::backends::MailboxPermissions,
+    ) -> ResultFuture<()> {
+        Err(MeliError::new(
+            "Setting mailbox permissions is not possible for the mbox backend.",
+        ))
+    }
+
+    fn search(
+        &self,
+        _query: crate::search::Query,
+        _mailbox_hash: Option<MailboxHash>,
+    ) -> ResultFuture<SmallVec<[EnvelopeHash; 512]>> {
+        Err(
+            MeliError::new("Search is unimplemented for the mbox backend.")
+                .set_kind(ErrorKind::NotImplemented),
+        )
+    }
+
+    fn create_mailbox(
+        &mut self,
+        _new_path: String,
+    ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)> {
+        Err(
+            MeliError::new("Creating mailboxes is unimplemented for the mbox backend.")
+                .set_kind(ErrorKind::NotImplemented),
+        )
+    }
 }
 
 macro_rules! get_conf_val {
diff --git a/melib/src/backends/nntp.rs b/melib/src/backends/nntp.rs
index a6c38864..695242f8 100644
--- a/melib/src/backends/nntp.rs
+++ b/melib/src/backends/nntp.rs
@@ -367,7 +367,10 @@ impl MailBackend for NntpType {
     }
 
     fn watch(&self) -> ResultFuture<()> {
-        Err(MeliError::new("Watching is currently uniplemented for nntp backend").set_kind(ErrorKind::NotImplemented))
+        Err(
+            MeliError::new("Watching is currently uniplemented for nntp backend")
+                .set_kind(ErrorKind::NotImplemented),
+        )
     }
 
     fn operation(&self, env_hash: EnvelopeHash) -> Result<Box<dyn BackendOp>> {
@@ -440,14 +443,18 @@ impl MailBackend for NntpType {
         &mut self,
         _path: String,
     ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)> {
-        Err(MeliError::new("Creating mailbox is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Creating mailbox is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn delete_mailbox(
         &mut self,
         _mailbox_hash: MailboxHash,
     ) -> ResultFuture<HashMap<MailboxHash, Mailbox>> {
-        Err(MeliError::new("Deleting a mailbox is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Deleting a mailbox is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn set_mailbox_subscription(
@@ -455,7 +462,9 @@ impl MailBackend for NntpType {
         _mailbox_hash: MailboxHash,
         _new_val: bool,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Setting mailbox description is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Setting mailbox description is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn rename_mailbox(
@@ -463,7 +472,9 @@ impl MailBackend for NntpType {
         _mailbox_hash: MailboxHash,
         _new_path: String,
     ) -> ResultFuture<Mailbox> {
-        Err(MeliError::new("Renaming mailbox is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Renaming mailbox is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn set_mailbox_permissions(
@@ -471,7 +482,9 @@ impl MailBackend for NntpType {
         _mailbox_hash: MailboxHash,
         _val: crate::backends::MailboxPermissions,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Setting mailbox permissions is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Setting mailbox permissions is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn search(
@@ -479,7 +492,9 @@ impl MailBackend for NntpType {
         _query: crate::search::Query,
         _mailbox_hash: Option<MailboxHash>,
     ) -> ResultFuture<SmallVec<[EnvelopeHash; 512]>> {
-        Err(MeliError::new("Searching is currently unimplemented for nntp backend."))
+        Err(MeliError::new(
+            "Searching is currently unimplemented for nntp backend.",
+        ))
     }
 
     fn submit(
diff --git a/melib/src/backends/notmuch.rs b/melib/src/backends/notmuch.rs
index 948a1c51..16dd6508 100644
--- a/melib/src/backends/notmuch.rs
+++ b/melib/src/backends/notmuch.rs
@@ -754,7 +754,9 @@ impl MailBackend for NotmuchDb {
         _destination_mailbox_hash: MailboxHash,
         _move_: bool,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Copying messages is currently unimplemented for notmuch backend"))
+        Err(MeliError::new(
+            "Copying messages is currently unimplemented for notmuch backend",
+        ))
     }
 
     fn set_flags(
@@ -874,7 +876,9 @@ impl MailBackend for NotmuchDb {
         _env_hashes: EnvelopeHashBatch,
         _mailbox_hash: MailboxHash,
     ) -> ResultFuture<()> {
-        Err(MeliError::new("Deleting messages is currently unimplemented for notmuch backend"))
+        Err(MeliError::new(
+            "Deleting messages is currently unimplemented for notmuch backend",
+        ))
     }
 
     fn search(
@@ -925,6 +929,55 @@ impl MailBackend for NotmuchDb {
     fn as_any_mut(&mut self) -> &mut dyn Any {
         self
     }
+
+    fn delete_mailbox(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+    ) -> ResultFuture<HashMap<MailboxHash, Mailbox>> {
+        Err(MeliError::new(
+            "Deleting mailboxes is currently unimplemented for notmuch backend.",
+        ))
+    }
+
+    fn set_mailbox_subscription(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _val: bool,
+    ) -> ResultFuture<()> {
+        Err(MeliError::new(
+            "Mailbox subscriptions are not possible for the notmuch backend.",
+        ))
+    }
+
+    fn rename_mailbox(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _new_path: String,
+    ) -> ResultFuture<Mailbox> {
+        Err(MeliError::new(
+            "Renaming mailboxes is currently unimplemented for notmuch backend.",
+        ))
+    }
+
+    fn set_mailbox_permissions(
+        &mut self,
+        _mailbox_hash: MailboxHash,
+        _val: crate::backends::MailboxPermissions,
+    ) -> ResultFuture<()> {
+        Err(MeliError::new(
+            "Setting mailbox permissions is not possible for the notmuch backend.",
+        ))
+    }
+
+    fn create_mailbox(
+        &mut self,
+        _new_path: String,
+    ) -> ResultFuture<(MailboxHash, HashMap<MailboxHash, Mailbox>)> {
+        Err(
+            MeliError::new("Creating mailboxes is unimplemented for the notmuch backend.")
+                .set_kind(ErrorKind::NotImplemented),
+        )
+    }
 }
 
 #[derive(Debug)]
diff --git a/melib/src/conf.rs b/melib/src/conf.rs
index 7047215c..5ce85c71 100644
--- a/melib/src/conf.rs
+++ b/melib/src/conf.rs
@@ -172,7 +172,7 @@ mod strings {
     named_unit_variant!(ask);
 }
 
-#[derive(Copy, Debug, Clone, PartialEq)]
+#[derive(Copy, Debug, Clone, PartialEq, Eq)]
 pub enum ToggleFlag {
     Unset,
     InternalVal(bool),
diff --git a/melib/src/email/list_management.rs b/melib/src/email/list_management.rs
index 3ecbb202..b0e07d82 100644
--- a/melib/src/email/list_management.rs
+++ b/melib/src/email/list_management.rs
@@ -25,7 +25,7 @@ use super::Envelope;
 use smallvec::SmallVec;
 use std::convert::From;
 
-#[derive(Debug, PartialEq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum ListAction<'a> {
     Url(&'a [u8]),
     Email(&'a [u8]),
diff --git a/melib/src/error.rs b/melib/src/error.rs
index 06debaac..40a98550 100644
--- a/melib/src/error.rs
+++ b/melib/src/error.rs
@@ -34,7 +34,7 @@ use std::sync::Arc;
 
 pub type Result<T> = result::Result<T, MeliError>;
 
-#[derive(Debug, Copy, PartialEq, Clone)]
+#[derive(Debug, Copy, PartialEq, Eq, Clone)]
 pub enum NetworkErrorKind {
     /// Unspecified
     None,
@@ -312,7 +312,7 @@ impl From<isahc::http::StatusCode> for NetworkErrorKind {
     }
 }
 
-#[derive(Debug, Copy, PartialEq, Clone)]
+#[derive(Debug, Copy, PartialEq, Eq, Clone)]
 pub enum ErrorKind {
     None,
     External,
diff --git a/melib/src/gpgme/bindings.rs b/melib/src/gpgme/bindings.rs
index ddb61b0e..4883b899 100644
--- a/melib/src/gpgme/bindings.rs
+++ b/melib/src/gpgme/bindings.rs
@@ -24,6 +24,8 @@
 #![allow(non_snake_case)]
 #![allow(unused)]
 #![allow(dead_code)]
+#![allow(clippy::useless_transmute)]
+#![allow(clippy::too_many_arguments)]
 use libc::{off_t, time_t, FILE};
 
 /* automatically generated by rust-bindgen */
diff --git a/melib/src/gpgme/mod.rs b/melib/src/gpgme/mod.rs
index 9d8c4703..4a5926b0 100644
--- a/melib/src/gpgme/mod.rs
+++ b/melib/src/gpgme/mod.rs
@@ -64,7 +64,7 @@ mod bindings;
 use bindings::*;
 mod io;
 
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum GpgmeFlag {
     ///"auto-key-retrieve"
     AutoKeyRetrieve,
@@ -1314,12 +1314,14 @@ impl std::fmt::Debug for Key {
     }
 }
 
-impl std::cmp::PartialEq for Key {
+impl PartialEq for Key {
     fn eq(&self, other: &Key) -> bool {
         self.fingerprint() == other.fingerprint()
     }
 }
 
+impl Eq for Key {}
+
 impl Drop for Key {
     #[inline]
     fn drop(&mut self) {
diff --git a/melib/src/lib.rs b/melib/src/lib.rs
index 7aef047c..e1aa4cf1 100644
--- a/melib/src/lib.rs
+++ b/melib/src/lib.rs
@@ -240,7 +240,7 @@ pub mod shellexpand {
                         .components()
                         .last()
                         .map(|c| c.as_os_str())
-                        .unwrap_or(OsStr::from_bytes(b""));
+                        .unwrap_or_else(|| OsStr::from_bytes(b""));
                     let prefix = if let Some(p) = self.parent() {
                         p
                     } else {
diff --git a/melib/src/smtp.rs b/melib/src/smtp.rs
index b9643dd1..589bdfaa 100644
--- a/melib/src/smtp.rs
+++ b/melib/src/smtp.rs
@@ -88,7 +88,7 @@ use std::net::TcpStream;
 use std::process::Command;
 
 /// Kind of server security (StartTLS/TLS/None) the client should attempt
-#[derive(Debug, Copy, PartialEq, Clone, Serialize, Deserialize)]
+#[derive(Debug, Copy, PartialEq, Eq, Clone, Serialize, Deserialize)]
 #[serde(tag = "type")]
 pub enum SmtpSecurity {
     #[serde(alias = "starttls", alias = "STARTTLS")]
@@ -119,7 +119,7 @@ impl Default for SmtpSecurity {
 }
 
 /// Source of user's password for SMTP authentication
-#[derive(Debug, PartialEq, Clone, Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize)]
 #[serde(tag = "type", content = "value")]
 pub enum Password {
     #[serde(alias = "raw")]
@@ -129,7 +129,7 @@ pub enum Password {
 }
 
 /// Kind of server authentication the client should attempt
-#[derive(Debug, PartialEq, Clone, Serialize, Deserialize)]
+#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize)]
 #[serde(tag = "type")]
 pub enum SmtpAuth {
     #[serde(alias = "none")]
@@ -152,7 +152,7 @@ pub enum SmtpAuth {
     // md5, sasl, etc
 }
 
-#[derive(Debug, PartialEq, Clone, Serialize, Deserialize, Default)]
+#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize, Default)]
 pub struct SmtpAuthType {
     plain: bool,
     login: bool,
@@ -761,7 +761,7 @@ impl SmtpConnection {
 pub type ExpectedReplyCode = Option<(ReplyCode, &'static [ReplyCode])>;
 
 /// Recognized kinds of SMTP reply codes
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum ReplyCode {
     ///System status, or system help reply
     _211,
diff --git a/melib/src/text_processing/types.rs b/melib/src/text_processing/types.rs
index 1912e762..b088b79d 100644
--- a/melib/src/text_processing/types.rs
+++ b/melib/src/text_processing/types.rs
@@ -20,7 +20,7 @@
  */
 
 #[allow(clippy::upper_case_acronyms)]
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum LineBreakClass {
     BK,
     CM,
@@ -123,7 +123,7 @@ impl From<&str> for LineBreakClass {
     }
 }
 
-#[derive(PartialEq, Debug, Copy, Clone)]
+#[derive(PartialEq, Eq, Debug, Copy, Clone)]
 pub enum Reflow {
     No,
     All,
diff --git a/melib/src/thread.rs b/melib/src/thread.rs
index 69e47705..76ed82d8 100644
--- a/melib/src/thread.rs
+++ b/melib/src/thread.rs
@@ -452,13 +452,13 @@ impl SubjectPrefix for &str {
 
 /* Sorting states. */
 
-#[derive(Debug, Clone, PartialEq, Copy, Deserialize, Serialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Copy, Deserialize, Serialize)]
 pub enum SortOrder {
     Asc,
     Desc,
 }
 
-#[derive(Debug, Clone, PartialEq, Copy, Deserialize, Serialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Copy, Deserialize, Serialize)]
 pub enum SortField {
     Subject,
     Date,
@@ -550,6 +550,10 @@ impl Thread {
         self.attachments > 0
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.len == 0
+    }
+
     pub fn set_snoozed(&mut self, val: bool) {
         self.snoozed = val;
     }
@@ -654,6 +658,8 @@ impl PartialEq for ThreadNode {
     }
 }
 
+impl Eq for ThreadNode {}
+
 impl Threads {
     pub fn is_snoozed(&self, h: ThreadNodeHash) -> bool {
         self.thread_ref(self.thread_nodes[&h].group).snoozed()
@@ -1442,6 +1448,10 @@ impl Threads {
         self.hash_set.len()
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.hash_set.is_empty()
+    }
+
     pub fn root_len(&self) -> usize {
         self.tree_index.read().unwrap().len()
     }