Fix clippy warnings (#2108)

* Fix clippy warnings

* review feedback.

src/platform_impl/linux/x11/util/format.rs

@@ -23,9 +23,9 @@ impl Format {
 
     pub fn get_actual_size(&self) -> usize {
         match self {
-            &Format::Char => mem::size_of::<c_char>(),
-            &Format::Short => mem::size_of::<c_short>(),
-            &Format::Long => mem::size_of::<c_long>(),
+            Format::Char => mem::size_of::<c_char>(),
+            Format::Short => mem::size_of::<c_short>(),
+            Format::Long => mem::size_of::<c_long>(),
         }
     }
 }

src/platform_impl/linux/x11/util/geometry.rs

@@ -248,7 +248,7 @@ impl XConnection {
             );
 
             // The list of children isn't used
-            if children != ptr::null_mut() {
+            if !children.is_null() {
                 (self.xlib.XFree)(children as *mut _);
             }
 

src/platform_impl/linux/x11/util/icon.rs

@@ -27,7 +27,7 @@ impl Icon {
         data.push(rgba_icon.height as Cardinal);
         let pixels = rgba_icon.rgba.as_ptr() as *const Pixel;
         for pixel_index in 0..pixel_count {
-            let pixel = unsafe { &*pixels.offset(pixel_index as isize) };
+            let pixel = unsafe { &*pixels.add(pixel_index) };
             data.push(pixel.to_packed_argb());
         }
         data

src/platform_impl/linux/x11/util/keys.rs

@@ -36,7 +36,7 @@ impl Iterator for KeymapIter<'_> {
 
     fn next(&mut self) -> Option<ffi::KeyCode> {
         if self.item.is_none() {
-            while let Some((index, &item)) = self.iter.next() {
+            for (index, &item) in self.iter.by_ref() {
                 if item != 0 {
                     self.index = index;
                     self.item = Some(item);

src/platform_impl/linux/x11/util/modifiers.rs

@@ -151,7 +151,7 @@ impl ModifierKeyState {
 
     pub fn key_release(&mut self, keycode: ffi::KeyCode) {
         if let Some(modifier) = self.keys.remove(&keycode) {
-            if self.keys.values().find(|&&m| m == modifier).is_none() {
+            if !self.keys.values().any(|&m| m == modifier) {
                 set_modifier(&mut self.state, modifier, false);
             }
         }

src/platform_impl/linux/x11/util/randr.rs

@@ -39,15 +39,15 @@ impl XConnection {
     pub unsafe fn get_xft_dpi(&self) -> Option<f64> {
         (self.xlib.XrmInitialize)();
         let resource_manager_str = (self.xlib.XResourceManagerString)(self.display);
-        if resource_manager_str == ptr::null_mut() {
+        if resource_manager_str.is_null() {
             return None;
         }
         if let Ok(res) = ::std::ffi::CStr::from_ptr(resource_manager_str).to_str() {
             let name: &str = "Xft.dpi:\t";
-            for pair in res.split("\n") {
+            for pair in res.split('\n') {
                 if pair.starts_with(&name) {
                     let res = &pair[name.len()..];
-                    return f64::from_str(&res).ok();
+                    return f64::from_str(res).ok();
                 }
             }
         }

src/platform_impl/linux/x11/util/window_property.rs

@@ -97,7 +97,7 @@ impl XConnection {
                         quantity_returned,
                         new_data,
                     );*/
-                    data.extend_from_slice(&new_data);
+                    data.extend_from_slice(new_data);
                     // Fun fact: XGetWindowProperty allocates one extra byte at the end.
                     (self.xlib.XFree)(buf as _); // Don't try to access new_data after this.
                 } else {

src/platform_impl/linux/x11/util/wm.rs

@@ -62,11 +62,7 @@ impl XConnection {
 
             let wm_check = result.ok().and_then(|wm_check| wm_check.get(0).cloned());
 
-            if let Some(wm_check) = wm_check {
-                wm_check
-            } else {
-                return None;
-            }
+            wm_check?
         };
 
         // Querying the same property on the child window we were given, we should get this child
@@ -76,11 +72,7 @@ impl XConnection {
 
             let wm_check = result.ok().and_then(|wm_check| wm_check.get(0).cloned());
 
-            if let Some(wm_check) = wm_check {
-                wm_check
-            } else {
-                return None;
-            }
+            wm_check?
         };
 
         // These values should be the same.