Add dyn keyword to Trait objects

And fix some unused var warnings as well

21 files changed, 62 insertions, 76 deletions

diff --git a/melib/src/backends.rs b/melib/src/backends.rs
index 94863652..fe7ee1a4 100644
--- a/melib/src/backends.rs
+++ b/melib/src/backends.rs
@@ -37,12 +37,13 @@ use std::ops::Deref;
 use fnv::FnvHashMap;
 use std;
 
-pub type BackendCreator = Box<Fn(&AccountSettings, Box<Fn(&str) -> bool>) -> Box<MailBackend>>;
+pub type BackendCreator =
+    Box<dyn Fn(&AccountSettings, Box<dyn Fn(&str) -> bool>) -> Box<dyn MailBackend>>;
 
 /// A hashmap containing all available mail backends.
 /// An abstraction over any available backends.
 pub struct Backends {
-    map: FnvHashMap<std::string::String, Box<Fn() -> BackendCreator>>,
+    map: FnvHashMap<std::string::String, Box<dyn Fn() -> BackendCreator>>,
 }
 
 impl Default for Backends {
@@ -78,7 +79,7 @@ impl Backends {
         self.map[key]()
     }
 
-    pub fn register(&mut self, key: String, backend: Box<Fn() -> BackendCreator>) {
+    pub fn register(&mut self, key: String, backend: Box<dyn Fn() -> BackendCreator>) {
         if self.map.contains_key(&key) {
             panic!("{} is an already registered backend", key);
         }
@@ -116,9 +117,9 @@ impl RefreshEvent {
 /// A `RefreshEventConsumer` is a boxed closure that must be used to consume a `RefreshEvent` and
 /// send it to a UI provided channel. We need this level of abstraction to provide an interface for
 /// all users of mailbox refresh events.
-pub struct RefreshEventConsumer(Box<Fn(RefreshEvent) -> () + Send + Sync>);
+pub struct RefreshEventConsumer(Box<dyn Fn(RefreshEvent) -> () + Send + Sync>);
 impl RefreshEventConsumer {
-    pub fn new(b: Box<Fn(RefreshEvent) -> () + Send + Sync>) -> Self {
+    pub fn new(b: Box<dyn Fn(RefreshEvent) -> () + Send + Sync>) -> Self {
         RefreshEventConsumer(b)
     }
     pub fn send(&self, r: RefreshEvent) {
@@ -126,7 +127,7 @@ impl RefreshEventConsumer {
     }
 }
 
-pub struct NotifyFn(Box<Fn(FolderHash) -> () + Send + Sync>);
+pub struct NotifyFn(Box<dyn Fn(FolderHash) -> () + Send + Sync>);
 
 impl fmt::Debug for NotifyFn {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -134,14 +135,14 @@ impl fmt::Debug for NotifyFn {
     }
 }
 
-impl From<Box<Fn(FolderHash) -> () + Send + Sync>> for NotifyFn {
-    fn from(kind: Box<Fn(FolderHash) -> () + Send + Sync>) -> Self {
+impl From<Box<dyn Fn(FolderHash) -> () + Send + Sync>> for NotifyFn {
+    fn from(kind: Box<dyn Fn(FolderHash) -> () + Send + Sync>) -> Self {
         NotifyFn(kind)
     }
 }
 
 impl NotifyFn {
-    pub fn new(b: Box<Fn(FolderHash) -> () + Send + Sync>) -> Self {
+    pub fn new(b: Box<dyn Fn(FolderHash) -> () + Send + Sync>) -> Self {
         NotifyFn(b)
     }
     pub fn notify(&self, f: FolderHash) {
@@ -164,10 +165,10 @@ pub trait MailBackend: ::std::fmt::Debug {
     fn get(&mut self, folder: &Folder) -> Async<Result<Vec<Envelope>>>;
     fn watch(&self, sender: RefreshEventConsumer) -> Result<()>;
     fn folders(&self) -> FnvHashMap<FolderHash, Folder>;
-    fn operation(&self, hash: EnvelopeHash, folder_hash: FolderHash) -> Box<BackendOp>;
+    fn operation(&self, hash: EnvelopeHash, folder_hash: FolderHash) -> Box<dyn BackendOp>;
 
     fn save(&self, bytes: &[u8], folder: &str, flags: Option<Flag>) -> Result<()>;
-    fn folder_operation(&mut self, path: &str, op: FolderOperation) -> Result<()> {
+    fn folder_operation(&mut self, _path: &str, _op: FolderOperation) -> Result<()> {
         Ok(())
     }
 }
@@ -234,11 +235,11 @@ pub trait BackendOp: ::std::fmt::Debug + ::std::marker::Send {
 /// Seen flag when fetching an envelope)
 #[derive(Debug)]
 pub struct ReadOnlyOp {
-    op: Box<BackendOp>,
+    op: Box<dyn BackendOp>,
 }
 
 impl ReadOnlyOp {
-    pub fn new(op: Box<BackendOp>) -> Box<BackendOp> {
+    pub fn new(op: Box<dyn BackendOp>) -> Box<dyn BackendOp> {
         Box::new(ReadOnlyOp { op })
     }
 }
diff --git a/melib/src/backends/imap.rs b/melib/src/backends/imap.rs
index 99a51d71..d68ff490 100644
--- a/melib/src/backends/imap.rs
+++ b/melib/src/backends/imap.rs
@@ -245,7 +245,7 @@ impl MailBackend for ImapType {
             .collect()
     }
 
-    fn operation(&self, hash: EnvelopeHash, _folder_hash: FolderHash) -> Box<BackendOp> {
+    fn operation(&self, hash: EnvelopeHash, _folder_hash: FolderHash) -> Box<dyn BackendOp> {
         let (uid, folder_hash) = self.hash_index.lock().unwrap()[&hash];
         Box::new(ImapOp::new(
             uid,
@@ -400,7 +400,7 @@ macro_rules! exit_on_error {
     }
 }
 impl ImapType {
-    pub fn new(s: &AccountSettings, is_subscribed: Box<Fn(&str) -> bool>) -> Self {
+    pub fn new(s: &AccountSettings, is_subscribed: Box<dyn Fn(&str) -> bool>) -> Self {
         use std::io::prelude::*;
         use std::net::TcpStream;
         debug!(s);
diff --git a/melib/src/backends/imap/watch.rs b/melib/src/backends/imap/watch.rs
index 8528549f..7819be07 100644
--- a/melib/src/backends/imap/watch.rs
+++ b/melib/src/backends/imap/watch.rs
@@ -57,7 +57,7 @@ pub fn poll_with_examine(kit: ImapWatchKit) {
     let mut response = String::with_capacity(8 * 1024);
     loop {
         std::thread::sleep(std::time::Duration::from_millis(5 * 60 * 1000));
-        for (hash, folder) in &folders {
+        for folder in folders.values() {
             examine_updates(folder, &sender, &mut conn, &hash_index, &uid_index);
         }
         let mut main_conn = main_conn.lock().unwrap();
@@ -318,11 +318,6 @@ pub fn idle(kit: ImapWatchKit) {
             }
         }
     }
-    debug!("failure");
-    sender.send(RefreshEvent {
-        hash: folder_hash,
-        kind: RefreshEventKind::Failure(MeliError::new("conn_error")),
-    });
 }
 
 fn examine_updates(
diff --git a/melib/src/backends/maildir/backend.rs b/melib/src/backends/maildir/backend.rs
index 9a7b50e7..46b51eec 100644
--- a/melib/src/backends/maildir/backend.rs
+++ b/melib/src/backends/maildir/backend.rs
@@ -460,7 +460,7 @@ impl MailBackend for MaildirType {
         Ok(())
     }
 
-    fn operation(&self, hash: EnvelopeHash, folder_hash: FolderHash) -> Box<BackendOp> {
+    fn operation(&self, hash: EnvelopeHash, folder_hash: FolderHash) -> Box<dyn BackendOp> {
         Box::new(MaildirOp::new(hash, self.hash_indexes.clone(), folder_hash))
     }
 
@@ -529,7 +529,7 @@ impl MailBackend for MaildirType {
 }
 
 impl MaildirType {
-    pub fn new(settings: &AccountSettings, is_subscribed: Box<Fn(&str) -> bool>) -> Self {
+    pub fn new(settings: &AccountSettings, is_subscribed: Box<dyn Fn(&str) -> bool>) -> Self {
         let mut folders: FnvHashMap<FolderHash, MaildirFolder> = Default::default();
         fn recurse_folders<P: AsRef<Path>>(
             folders: &mut FnvHashMap<FolderHash, MaildirFolder>,
diff --git a/melib/src/backends/mbox.rs b/melib/src/backends/mbox.rs
index 84b7a4b4..51d6231f 100644
--- a/melib/src/backends/mbox.rs
+++ b/melib/src/backends/mbox.rs
@@ -242,7 +242,7 @@ impl BackendOp for MboxOp {
         flags
     }
 
-    fn set_flag(&mut self, envelope: &mut Envelope, flag: Flag) -> Result<()> {
+    fn set_flag(&mut self, _envelope: &mut Envelope, _flag: Flag) -> Result<()> {
         Ok(())
     }
 }
@@ -526,7 +526,7 @@ impl MailBackend for MboxType {
             .map(|(h, f)| (*h, f.clone() as Folder))
             .collect()
     }
-    fn operation(&self, hash: EnvelopeHash, _folder_hash: FolderHash) -> Box<BackendOp> {
+    fn operation(&self, hash: EnvelopeHash, _folder_hash: FolderHash) -> Box<dyn BackendOp> {
         let (offset, length) = {
             let index = self.index.lock().unwrap();
             index[&hash]
@@ -540,7 +540,7 @@ impl MailBackend for MboxType {
 }
 
 impl MboxType {
-    pub fn new(s: &AccountSettings, _is_subscribed: Box<Fn(&str) -> bool>) -> Self {
+    pub fn new(s: &AccountSettings, _is_subscribed: Box<dyn Fn(&str) -> bool>) -> Self {
         let path = Path::new(s.root_folder.as_str());
         if !path.exists() {
             panic!(
diff --git a/melib/src/email.rs b/melib/src/email.rs
index 4bfba2ca..1775cb5e 100644
--- a/melib/src/email.rs
+++ b/melib/src/email.rs
@@ -387,7 +387,7 @@ impl Envelope {
         }
         Err(MeliError::new("Couldn't parse mail."))
     }
-    pub fn from_token(mut operation: Box<BackendOp>, hash: EnvelopeHash) -> Option<Envelope> {
+    pub fn from_token(mut operation: Box<dyn BackendOp>, hash: EnvelopeHash) -> Option<Envelope> {
         let mut e = Envelope::new(hash);
         e.flags = operation.fetch_flags();
         if let Ok(bytes) = operation.as_bytes() {
@@ -522,7 +522,7 @@ impl Envelope {
         Ok(())
     }
 
-    pub fn populate_headers_from_token(&mut self, mut operation: Box<BackendOp>) -> Result<()> {
+    pub fn populate_headers_from_token(&mut self, mut operation: Box<dyn BackendOp>) -> Result<()> {
         let headers = operation.fetch_headers()?;
         self.populate_headers(headers)
     }
@@ -563,7 +563,7 @@ impl Envelope {
         let _strings: Vec<String> = self.to.iter().map(|a| format!("{}", a)).collect();
         _strings.join(", ")
     }
-    pub fn bytes(&self, mut operation: Box<BackendOp>) -> Vec<u8> {
+    pub fn bytes(&self, mut operation: Box<dyn BackendOp>) -> Vec<u8> {
         operation
             .as_bytes()
             .map(|v| v.into())
@@ -608,7 +608,7 @@ impl Envelope {
                 })
             })
     }
-    pub fn body(&self, mut operation: Box<BackendOp>) -> Attachment {
+    pub fn body(&self, mut operation: Box<dyn BackendOp>) -> Attachment {
         debug!("searching body for {:?}", self.message_id_display());
         let file = operation.as_bytes();
         self.body_bytes(file.unwrap())
@@ -781,7 +781,7 @@ impl Envelope {
     pub fn set_datetime(&mut self, new_val: chrono::DateTime<chrono::FixedOffset>) {
         self.timestamp = new_val.timestamp() as UnixTimestamp;
     }
-    pub fn set_flag(&mut self, f: Flag, mut operation: Box<BackendOp>) -> Result<()> {
+    pub fn set_flag(&mut self, f: Flag, mut operation: Box<dyn BackendOp>) -> Result<()> {
         self.flags.toggle(f);
         operation.set_flag(self, f)?;
         Ok(())
@@ -792,14 +792,14 @@ impl Envelope {
     pub fn flags(&self) -> Flag {
         self.flags
     }
-    pub fn set_seen(&mut self, operation: Box<BackendOp>) -> Result<()> {
+    pub fn set_seen(&mut self, operation: Box<dyn BackendOp>) -> Result<()> {
         if !self.flags.contains(Flag::SEEN) {
             self.set_flag(Flag::SEEN, operation)
         } else {
             Ok(())
         }
     }
-    pub fn set_unseen(&mut self, operation: Box<BackendOp>) -> Result<()> {
+    pub fn set_unseen(&mut self, operation: Box<dyn BackendOp>) -> Result<()> {
         if self.flags.contains(Flag::SEEN) {
             self.set_flag(Flag::SEEN, operation)
         } else {
diff --git a/melib/src/email/attachments.rs b/melib/src/email/attachments.rs
index 04fec24c..bea56b18 100644
--- a/melib/src/email/attachments.rs
+++ b/melib/src/email/attachments.rs
@@ -441,7 +441,7 @@ fn decode_rfc822(_raw: &[u8]) -> Attachment {
     builder.build()
 }
 
-type Filter<'a> = Box<FnMut(&'a Attachment, &mut Vec<u8>) -> () + 'a>;
+type Filter<'a> = Box<dyn FnMut(&'a Attachment, &mut Vec<u8>) -> () + 'a>;
 
 fn decode_rec_helper<'a>(a: &'a Attachment, filter: &mut Option<Filter<'a>>) -> Vec<u8> {
     match a.content_type {
diff --git a/melib/src/email/compose.rs b/melib/src/email/compose.rs
index b9d915e6..26ca3219 100644
--- a/melib/src/email/compose.rs
+++ b/melib/src/email/compose.rs
@@ -113,7 +113,7 @@ impl str::FromStr for Draft {
 }
 
 impl Draft {
-    pub fn edit(envelope: &Envelope, mut op: Box<BackendOp>) -> Self {
+    pub fn edit(envelope: &Envelope, mut op: Box<dyn BackendOp>) -> Self {
         let mut ret = Draft::default();
         //TODO: Inform user if error
         {
diff --git a/melib/src/email/parser.rs b/melib/src/email/parser.rs
index 89ea8d4a..28a3c940 100644
--- a/melib/src/email/parser.rs
+++ b/melib/src/email/parser.rs
@@ -247,7 +247,7 @@ pub fn headers_raw(input: &[u8]) -> IResult<&[u8], &[u8]> {
     if input.is_empty() {
         return IResult::Incomplete(Needed::Unknown);
     }
-    for (i, x) in input.iter().enumerate() {
+    for i in 0..input.len() {
         if input[i..].starts_with(b"\n\n") {
             return IResult::Done(&input[(i + 1)..], &input[0..=i]);
         } else if input[i..].starts_with(b"\r\n\r\n") {
diff --git a/melib/src/thread.rs b/melib/src/thread.rs
index b0c5d8f6..9e76879d 100644
--- a/melib/src/thread.rs
+++ b/melib/src/thread.rs
@@ -1107,6 +1107,7 @@ impl Threads {
         }
     }
 
+    /*
     fn link_envelope(&mut self, envelope: &mut Envelope) {
         let t_idx: ThreadHash = {
             let m_id = envelope.message_id().raw();
@@ -1215,7 +1216,7 @@ impl Threads {
             }
             ref_ptr = parent_id;
         }
-    }
+    }*/
 
     fn tree_insert_root(&mut self, new_id: ThreadHash, envelopes: &Envelopes) {
         debug_assert!(
diff --git a/ui/src/components/contacts/contact_list.rs b/ui/src/components/contacts/contact_list.rs
index 3807bc12..a718ef0f 100644
--- a/ui/src/components/contacts/contact_list.rs
+++ b/ui/src/components/contacts/contact_list.rs
@@ -22,7 +22,7 @@ pub struct ContactList {
 
     mode: ViewMode,
     dirty: bool,
-    view: Option<Box<Component>>,
+    view: Option<Box<dyn Component>>,
     id: ComponentId,
 }
 
diff --git a/ui/src/components/indexer/index.rs b/ui/src/components/indexer/index.rs
index 0472e67a..585b3703 100644
--- a/ui/src/components/indexer/index.rs
+++ b/ui/src/components/indexer/index.rs
@@ -33,7 +33,7 @@ pub struct Index {
     dirty: bool,
     state: IndexState,
 
-    content: Box<IndexContent>,
+    content: Box<dyn IndexContent>,
     id: ComponentId,
 }
 
@@ -117,7 +117,6 @@ impl Component for Index {
             IndexState::Unfocused => {
                 self.content.draw(grid, area, context);
             }
-            //IndexState::Search => unreachable!(),
         }
 
         self.dirty = false;
diff --git a/ui/src/components/mail/listing/compact.rs b/ui/src/components/mail/listing/compact.rs
index 72a7a1fa..c557e1d7 100644
--- a/ui/src/components/mail/listing/compact.rs
+++ b/ui/src/components/mail/listing/compact.rs
@@ -112,11 +112,6 @@ impl ListingTrait for CompactListing {
             return;
         }
         let i = self.get_envelope_under_cursor(idx, context);
-        let account = &context.accounts[self.cursor_pos.0];
-        let is_seen = {
-            let root_envelope: &Envelope = &account.get_env(&i);
-            root_envelope.is_seen()
-        };
 
         let fg_color = self.data_columns.columns[0][(0, idx)].fg();
         let bg_color = if self.cursor_pos.2 == idx {
@@ -128,7 +123,6 @@ impl ListingTrait for CompactListing {
         };
 
         let (upper_left, bottom_right) = area;
-        let (width, height) = self.data_columns.columns[3].size();
         change_colors(grid, area, fg_color, bg_color);
         let mut x = get_x(upper_left)
             + self.data_columns.widths[0]
diff --git a/ui/src/components/mail/listing/thread.rs b/ui/src/components/mail/listing/thread.rs
index e9fb9d29..6a1169e2 100644
--- a/ui/src/components/mail/listing/thread.rs
+++ b/ui/src/components/mail/listing/thread.rs
@@ -502,12 +502,8 @@ impl Component for ThreadListing {
                     false
                 } else {
                     let account = &mut context.accounts[self.cursor_pos.0];
-                    let (hash, is_seen) = {
-                        let envelope: &Envelope =
-                            &account.get_env(&self.locations[self.cursor_pos.2]);
-                        (envelope.hash(), envelope.is_seen())
-                    };
-                    is_seen
+                    let envelope: &Envelope = &account.get_env(&self.locations[self.cursor_pos.2]);
+                    envelope.is_seen()
                 }
             };
 
diff --git a/ui/src/components/mail/view.rs b/ui/src/components/mail/view.rs
index 0e7a24be..a8cc3d80 100644
--- a/ui/src/components/mail/view.rs
+++ b/ui/src/components/mail/view.rs
@@ -68,7 +68,7 @@ impl ViewMode {
 pub struct MailView {
     coordinates: (usize, usize, EnvelopeHash),
     pager: Option<Pager>,
-    subview: Option<Box<Component>>,
+    subview: Option<Box<dyn Component>>,
     dirty: bool,
     mode: ViewMode,
     expand_headers: bool,
@@ -89,7 +89,7 @@ impl MailView {
     pub fn new(
         coordinates: (usize, usize, EnvelopeHash),
         pager: Option<Pager>,
-        subview: Option<Box<Component>>,
+        subview: Option<Box<dyn Component>>,
     ) -> Self {
         MailView {
             coordinates,
diff --git a/ui/src/components/mail/view/envelope.rs b/ui/src/components/mail/view/envelope.rs
index 3cb4a516..58e49a6d 100644
--- a/ui/src/components/mail/view/envelope.rs
+++ b/ui/src/components/mail/view/envelope.rs
@@ -48,7 +48,7 @@ impl ViewMode {
 #[derive(Debug)]
 pub struct EnvelopeView {
     pager: Option<Pager>,
-    subview: Option<Box<Component>>,
+    subview: Option<Box<dyn Component>>,
     dirty: bool,
     mode: ViewMode,
     wrapper: EnvelopeWrapper,
@@ -69,7 +69,7 @@ impl EnvelopeView {
     pub fn new(
         wrapper: EnvelopeWrapper,
         pager: Option<Pager>,
-        subview: Option<Box<Component>>,
+        subview: Option<Box<dyn Component>>,
         account_pos: usize,
     ) -> Self {
         EnvelopeView {
diff --git a/ui/src/components/utilities.rs b/ui/src/components/utilities.rs
index b150627a..d1eb7409 100644
--- a/ui/src/components/utilities.rs
+++ b/ui/src/components/utilities.rs
@@ -30,8 +30,8 @@ pub use self::widgets::*;
 /// A horizontally split in half container.
 #[derive(Debug)]
 pub struct HSplit {
-    top: Box<Component>,
-    bottom: Box<Component>,
+    top: Box<dyn Component>,
+    bottom: Box<dyn Component>,
     show_divider: bool,
     ratio: usize, // bottom/whole height * 100
     id: ComponentId,
@@ -46,8 +46,8 @@ impl fmt::Display for HSplit {
 
 impl HSplit {
     pub fn new(
-        top: Box<Component>,
-        bottom: Box<Component>,
+        top: Box<dyn Component>,
+        bottom: Box<dyn Component>,
         ratio: usize,
         show_divider: bool,
     ) -> Self {
@@ -125,8 +125,8 @@ impl Component for HSplit {
 /// A vertically split in half container.
 #[derive(Debug)]
 pub struct VSplit {
-    left: Box<Component>,
-    right: Box<Component>,
+    left: Box<dyn Component>,
+    right: Box<dyn Component>,
     show_divider: bool,
     prev_visibility: (bool, bool),
     /// This is the width of the right container to the entire width.
@@ -143,8 +143,8 @@ impl fmt::Display for VSplit {
 
 impl VSplit {
     pub fn new(
-        left: Box<Component>,
-        right: Box<Component>,
+        left: Box<dyn Component>,
+        right: Box<dyn Component>,
         ratio: usize,
         show_divider: bool,
     ) -> Self {
@@ -602,7 +602,7 @@ impl Component for Pager {
 /// Status bar.
 #[derive(Debug)]
 pub struct StatusBar {
-    container: Box<Component>,
+    container: Box<dyn Component>,
     status: String,
     notifications: VecDeque<String>,
     ex_buffer: Field,
@@ -624,7 +624,7 @@ impl fmt::Display for StatusBar {
 }
 
 impl StatusBar {
-    pub fn new(container: Box<Component>) -> Self {
+    pub fn new(container: Box<dyn Component>) -> Self {
         StatusBar {
             container,
             status: String::with_capacity(256),
@@ -1120,7 +1120,7 @@ impl Component for Progress {
 #[derive(Debug)]
 pub struct Tabbed {
     pinned: usize,
-    children: Vec<Box<Component>>,
+    children: Vec<Box<dyn Component>>,
     cursor_pos: usize,
 
     show_shortcuts: bool,
@@ -1130,7 +1130,7 @@ pub struct Tabbed {
 }
 
 impl Tabbed {
-    pub fn new(children: Vec<Box<Component>>) -> Self {
+    pub fn new(children: Vec<Box<dyn Component>>) -> Self {
         let pinned = children.len();
         Tabbed {
             pinned,
@@ -1194,7 +1194,7 @@ impl Tabbed {
 
         context.dirty_areas.push_back(area);
     }
-    pub fn add_component(&mut self, new: Box<Component>) {
+    pub fn add_component(&mut self, new: Box<dyn Component>) {
         self.children.push(new);
     }
 }
diff --git a/ui/src/components/utilities/widgets.rs b/ui/src/components/utilities/widgets.rs
index b84f0ea2..387fd906 100644
--- a/ui/src/components/utilities/widgets.rs
+++ b/ui/src/components/utilities/widgets.rs
@@ -1,7 +1,7 @@
 use super::*;
 use fnv::FnvHashMap;
 
-type AutoCompleteFn = Box<Fn(&Context, &str) -> Vec<AutoCompleteEntry> + Send>;
+type AutoCompleteFn = Box<dyn Fn(&Context, &str) -> Vec<AutoCompleteEntry> + Send>;
 
 #[derive(Debug, PartialEq)]
 enum FormFocus {
diff --git a/ui/src/conf/accounts.rs b/ui/src/conf/accounts.rs
index 4f84f8eb..3a0525ba 100644
--- a/ui/src/conf/accounts.rs
+++ b/ui/src/conf/accounts.rs
@@ -317,7 +317,7 @@ impl Account {
     }
     fn new_worker(
         folder: Folder,
-        backend: &mut Box<MailBackend>,
+        backend: &mut Box<dyn MailBackend>,
         notify_fn: Arc<NotifyFn>,
     ) -> Worker {
         let mailbox_handle = backend.get(&folder);
@@ -617,7 +617,7 @@ impl Account {
     pub fn contains_key(&self, h: EnvelopeHash) -> bool {
         self.collection.contains_key(&h)
     }
-    pub fn operation(&self, h: EnvelopeHash) -> Box<BackendOp> {
+    pub fn operation(&self, h: EnvelopeHash) -> Box<dyn BackendOp> {
         for mailbox in self.folders.values() {
             match mailbox {
                 MailboxEntry::Available(ref m) | MailboxEntry::Parsing(ref m, _, _) => {
diff --git a/ui/src/execute/actions.rs b/ui/src/execute/actions.rs
index ec62db90..02074bef 100644
--- a/ui/src/execute/actions.rs
+++ b/ui/src/execute/actions.rs
@@ -45,7 +45,7 @@ pub enum ListingAction {
 
 #[derive(Debug)]
 pub enum TabAction {
-    New(Option<Box<Component>>),
+    New(Option<Box<dyn Component>>),
     NewDraft(usize, Option<Draft>),
     Reply((usize, usize, usize), ThreadHash), // thread coordinates (account, mailbox, root_set idx) and thread hash
     Close,
diff --git a/ui/src/state.rs b/ui/src/state.rs
index 9fd5ae47..27084608 100644
--- a/ui/src/state.rs
+++ b/ui/src/state.rs
@@ -21,7 +21,7 @@
 
 /*! The application's state.
 
-The UI crate has an Box<Component>-Component-System design. The System part, is also the application's state, so they're both merged in the `State` struct.
+The UI crate has an Box<dyn Component>-Component-System design. The System part, is also the application's state, so they're both merged in the `State` struct.
 
 `State` owns all the Components of the UI. In the application's main event loop, input is handed to the state in the form of `UIEvent` objects which traverse the component graph. Components decide to handle each input or not.
 
@@ -128,7 +128,7 @@ pub struct State {
     stdout: Option<StateStdout>,
     child: Option<ForkType>,
     pub mode: UIMode,
-    components: Vec<Box<Component>>,
+    components: Vec<Box<dyn Component>>,
     pub context: Context,
     threads: FnvHashMap<thread::ThreadId, (chan::Sender<bool>, thread::JoinHandle<()>)>,
     work_controller: WorkController,
@@ -477,7 +477,7 @@ impl State {
             );
         }
     }
-    pub fn register_component(&mut self, component: Box<Component>) {
+    pub fn register_component(&mut self, component: Box<dyn Component>) {
         self.components.push(component);
     }
     /// Convert user commands to actions/method calls.