clippy:Fix clippy problems in components/scripts/binding (servo#31893)

* constants have by default a static lifetime

* constants have by default a static lifetime

* unneeded unit expression

* unneeded unit expression

* Box of default value

* casting raw pointers

* casting raw pointers

components/script/dom/bindings/buffer_source.rs

@@ -124,7 +124,7 @@ where
 {
     pub fn default() -> HeapBufferSource<T> {
         HeapBufferSource {
-            buffer_source: BufferSource::Default(Box::new(Heap::default())),
+            buffer_source: BufferSource::Default(Box::default()),
             phantom: PhantomData,
         }
     }

components/script/dom/bindings/callback.rs

@@ -127,7 +127,7 @@ pub trait CallbackContainer {
     ///
     /// ["callback context"]: https://heycam.github.io/webidl/#dfn-callback-context
     fn incumbent(&self) -> Option<&GlobalScope> {
-        self.callback_holder().incumbent.as_ref().map(Dom::deref)
+        self.callback_holder().incumbent.as_deref()
     }
 }
 

components/script/dom/bindings/conversions.rs

@@ -282,7 +282,7 @@ impl FromJSValConvertible for USVString {
         let mut length = 0;
         let chars = JS_GetTwoByteStringCharsAndLength(cx, ptr::null(), jsstr, &mut length);
         assert!(!chars.is_null());
-        let char_vec = slice::from_raw_parts(chars as *const u16, length);
+        let char_vec = slice::from_raw_parts(chars, length);
         Ok(ConversionResult::Success(USVString(
             String::from_utf16_lossy(char_vec),
         )))
@@ -395,7 +395,7 @@ pub unsafe fn get_dom_class(obj: *mut JSObject) -> Result<&'static DOMClass, ()>
     if is_dom_class(&*clasp) {
         trace!("plain old dom object");
         let domjsclass: *const DOMJSClass = clasp as *const DOMJSClass;
-        return Ok(&(&*domjsclass).dom_class);
+        return Ok(&(*domjsclass).dom_class);
     }
     if is_dom_proxy(obj) {
         trace!("proxy dom object");

components/script/dom/bluetoothuuid.rs

@@ -523,7 +523,7 @@ const BLUETOOTH_ASSIGNED_CHARCTERISTICS: &[(&str, u32)] = &[
 ];
 
 //https://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx
-const BLUETOOTH_ASSIGNED_DESCRIPTORS: &'static [(&'static str, u32)] = &[
+const BLUETOOTH_ASSIGNED_DESCRIPTORS: &'static [(&str, u32)] = &[
     (
         "org.bluetooth.descriptor.gatt.characteristic_extended_properties",
         0x2900_u32,
@@ -568,19 +568,18 @@ const CHARACTERISTIC_PREFIX: &str = "org.bluetooth.characteristic";
 const DESCRIPTOR_PREFIX: &str = "org.bluetooth.descriptor";
 const VALID_UUID_REGEX: &str = "^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$";
 // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/modules/bluetooth/BluetoothUUID.cpp?l=314
-const UUID_ERROR_MESSAGE: &'static str = "It must be a valid UUID alias (e.g. 0x1234), \
+const UUID_ERROR_MESSAGE: &str = "It must be a valid UUID alias (e.g. 0x1234), \
     UUID (lowercase hex characters e.g. '00001234-0000-1000-8000-00805f9b34fb'),\nor recognized standard name from";
 // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/modules/bluetooth/BluetoothUUID.cpp?l=321
-const SERVICES_ERROR_MESSAGE: &'static str =
+const SERVICES_ERROR_MESSAGE: &str =
     "https://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx\
      \ne.g. 'alert_notification'.";
 // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/modules/bluetooth/BluetoothUUID.cpp?l=327
-const CHARACTERISTIC_ERROR_MESSAGE: &'static str =
+const CHARACTERISTIC_ERROR_MESSAGE: &str =
     "https://developer.bluetooth.org/gatt/characteristics/Pages/\
      CharacteristicsHome.aspx\ne.g. 'aerobic_heart_rate_lower_limit'.";
 // https://cs.chromium.org/chromium/src/third_party/WebKit/Source/modules/bluetooth/BluetoothUUID.cpp?l=333
-const DESCRIPTOR_ERROR_MESSAGE: &'static str =
-    "https://developer.bluetooth.org/gatt/descriptors/Pages/\
+const DESCRIPTOR_ERROR_MESSAGE: &str = "https://developer.bluetooth.org/gatt/descriptors/Pages/\
      DescriptorsHomePage.aspx\ne.g. 'gatt.characteristic_presentation_format'.";
 
 #[allow(non_snake_case)]

components/script/dom/htmlformelement.rs

@@ -1125,7 +1125,6 @@ impl HTMLFormElement {
                     },
                     HTMLElementTypeId::HTMLObjectElement => {
                         // Unimplemented
-                        ()
                     },
                     HTMLElementTypeId::HTMLSelectElement => {
                         let select = child.downcast::<HTMLSelectElement>().unwrap();

components/script/dom/htmlinputelement.rs

@@ -83,8 +83,8 @@ use crate::textinput::KeyReaction::{
 use crate::textinput::Lines::Single;
 use crate::textinput::{Direction, SelectionDirection, TextInput, UTF16CodeUnits, UTF8Bytes};
 
-const DEFAULT_SUBMIT_VALUE: &'static str = "Submit";
-const DEFAULT_RESET_VALUE: &'static str = "Reset";
+const DEFAULT_SUBMIT_VALUE: &str = "Submit";
+const DEFAULT_RESET_VALUE: &str = "Reset";
 const PASSWORD_REPLACEMENT_CHAR: char = '●';
 
 #[derive(Clone, Copy, JSTraceable, PartialEq)]
@@ -2850,7 +2850,7 @@ impl Activatable for HTMLInputElement {
                 // https://html.spec.whatwg.org/multipage/#radio-button-state-(type=radio):activation-behavior
                 // Check if document owner is fully active
                 if !self.upcast::<Node>().is_connected() {
-                    return ();
+                    return;
                 }
                 let target = self.upcast::<EventTarget>();
                 target.fire_bubbling_event(atom!("input"));

components/script/dom/node.rs

@@ -1873,7 +1873,6 @@ impl Node {
         // Step 1.
         match parent.type_id() {
             NodeTypeId::Document(_) | NodeTypeId::DocumentFragment(_) | NodeTypeId::Element(..) => {
-                ()
             },
             _ => return Err(Error::HierarchyRequest),
         }
@@ -2640,7 +2639,6 @@ impl NodeMethods for Node {
         // Step 1.
         match self.type_id() {
             NodeTypeId::Document(_) | NodeTypeId::DocumentFragment(_) | NodeTypeId::Element(..) => {
-                ()
             },
             _ => return Err(Error::HierarchyRequest),
         }