Fix clippy warnings

src/backend/curses.rs

@@ -54,7 +54,7 @@ impl Backend for CursesBackend {
         for (col, row, cell) in content {
             // eprintln!("{:?}", cell);
             if row != last_row || col != last_col + 1 {
-                self.curses.move_rc(row as i32, col as i32);
+                self.curses.move_rc(i32::from(row), i32::from(col));
             }
             last_col = col;
             last_row = row;
@@ -111,7 +111,7 @@ impl Backend for CursesBackend {
         Ok((x as u16, y as u16))
     }
     fn set_cursor(&mut self, x: u16, y: u16) -> io::Result<()> {
-        self.curses.move_rc(x as i32, y as i32);
+        self.curses.move_rc(i32::from(x), i32::from(y));
         Ok(())
     }
     fn clear(&mut self) -> io::Result<()> {

src/backend/rustbox.rs

@@ -103,7 +103,7 @@ impl Into<rustbox::Color> for Color {
             Color::Cyan | Color::LightCyan => rustbox::Color::Cyan,
             Color::White => rustbox::Color::White,
             Color::Blue | Color::LightBlue => rustbox::Color::Blue,
-            Color::Indexed(i) => rustbox::Color::Byte(i as u16),
+            Color::Indexed(i) => rustbox::Color::Byte(u16::from(i)),
             Color::Rgb(r, g, b) => rustbox::Color::Byte(rgb_to_byte(r, g, b)),
         }
     }

src/style.rs

@@ -26,7 +26,7 @@ pub enum Color {
 impl Color {
     /// Returns a short code associated with the color, used for debug purpose
     /// only
-    pub(crate) fn code(&self) -> &str {
+    pub(crate) fn code(self) -> &'static str {
         match self {
             Color::Reset => "X",
             Color::Black => "b",
@@ -68,7 +68,7 @@ bitflags! {
 impl Modifier {
     /// Returns a short code associated with the color, used for debug purpose
     /// only
-    pub(crate) fn code(&self) -> String {
+    pub(crate) fn code(self) -> String {
         use std::fmt::Write;
 
         let mut result = String::new();

src/widgets/list.rs

@@ -1,5 +1,5 @@
-use std::iter;
-use std::iter::Iterator;
+use std::convert::AsRef;
+use std::iter::{self, Iterator};
 
 use unicode_width::UnicodeWidthStr;
 
@@ -166,7 +166,7 @@ impl<'b> SelectableList<'b> {
     where
         I: AsRef<str> + 'b,
     {
-        self.items = items.iter().map(|i| i.as_ref()).collect::<Vec<&str>>();
+        self.items = items.iter().map(AsRef::as_ref).collect::<Vec<&str>>();
         self
     }