Reduce cargo clippy warnings

src/widgets/audio/alsa_sound.rs

@@ -4,8 +4,8 @@ use crate::widgets::bar_widget::{BarWidget, BarWidgetImpl};
 
 use alsa::mixer::{Mixer, Selem, SelemChannelId, SelemId};
 
-const CARD_NAME: &'static str = "default";
-const SELEM_NAME: &'static str = "Master";
+const CARD_NAME: &str = "default";
+const SELEM_NAME: &str = "Master";
 const SELEM_ID: u32 = 0u32;
 
 #[inline]
@@ -15,8 +15,8 @@ fn alsa_error_to_io_error(fail: &'static str, err: &alsa::Error) -> ::std::io::E
     let errno = err
         .errno()
         .map(|errno| format!("; errno = {}", errno))
-        .unwrap_or(String::new());
-    return ::std::io::Error::new(kind, format!("{}: {}{}", fail, func, errno));
+        .unwrap_or_default();
+    ::std::io::Error::new(kind, format!("{}: {}{}", fail, func, errno))
 }
 
 #[inline]

src/widgets/audio/pulse_sound.rs

@@ -158,7 +158,7 @@ impl PulseAudioClient {
                             match req {
                                 PulseAudioClientRequest::GetDefaultDevice(s) => {
                                     introspector.get_server_info(move |info| {
-                                        let _res = PulseAudioClient::server_info_callback(
+                                        PulseAudioClient::server_info_callback(
                                             cl.clone(),
                                             l.clone(),
                                             info,
@@ -260,13 +260,12 @@ impl PulseAudioClient {
     }
 
     fn send(&self, request: PulseAudioClientRequest) -> Result<(), ::std::io::Error> {
-        let res = self.sender.send(request).map_err(|_e| {
+        self.sender.send(request).map_err(|_e| {
             ::std::io::Error::new(
                 ::std::io::ErrorKind::Other,
                 "unable to send pulseaudio request",
             )
-        });
-        res
+        })
     }
 
     fn server_info_callback<F>(s: Arc<Mutex<Self>>, listener: F, server_info: &ServerInfo)
@@ -371,10 +370,7 @@ impl PulseAudioSoundDevice {
             cl.default_sink.to_string()
         };
         (*inner.lock().unwrap()).name = Some(name.clone());
-        let device = PulseAudioSoundDevice {
-            client: cl,
-            inner: inner,
-        };
+        let device = PulseAudioSoundDevice { client: cl, inner };
         let (tx, rx) = channel();
         {
             let cl = client.lock().unwrap();
@@ -497,7 +493,7 @@ impl PulseAudio {
                 *dirty.lock().unwrap() = true;
                 sender.send(Cmd::Draw).unwrap();
             })?;
-            Ok(Box::new(PulseAudio { device: device }))
+            Ok(Box::new(PulseAudio { device }))
         })
     }
 }