Update code for some new clippy lints

examples/sine_synth.rs

@@ -91,7 +91,6 @@ impl Plugin for SineSynth {
         }
     }
 
-    #[allow(unknown_lints)]
     #[allow(unused_variables)]
     #[allow(clippy::single_match)]
     fn process_events(&mut self, events: &Events) {

src/api.rs

@@ -132,7 +132,6 @@ pub struct AEffect {
 impl AEffect {
     /// Return handle to Plugin object. Only works for plugins created using this library.
     // Supresses warning about returning a reference to a box
-    #[allow(unknown_lints)]
     #[allow(clippy::borrowed_box)]
     pub unsafe fn get_plugin(&mut self) -> &mut Box<dyn Plugin> {
         //FIXME: find a way to do this without resorting to transmuting via a box

src/host.rs

@@ -725,10 +725,8 @@ impl<T: Float> HostBuffer<T> {
     /// was created for, or if the sample arrays do not all have the same length.
     pub fn bind<'a, I, O>(&'a mut self, input_arrays: &[I], output_arrays: &mut [O]) -> AudioBuffer<'a, T>
     where
-        I: AsRef<[T]>,
-        O: AsMut<[T]>,
-        I: 'a,
-        O: 'a,
+        I: AsRef<[T]> + 'a,
+        O: AsMut<[T]> + 'a,
     {
         // Check that number of desired inputs and outputs fit in allocation
         if input_arrays.len() > self.inputs.len() {

src/lib.rs

@@ -187,7 +187,9 @@ pub fn main<T: Plugin + Default>(callback: HostCallbackProc) -> *mut AEffect {
     // Create a Box containing a zeroed AEffect. This is transmuted into a *mut pointer so that it
     // can be passed into the HostCallback `wrap` method. The AEffect is then updated after the vst
     // object is created so that the host still contains a raw pointer to the AEffect struct.
-    let effect = unsafe { Box::into_raw(Box::new(mem::zeroed::<AEffect>())) };
+    let effect = unsafe {
+        Box::into_raw(Box::new(mem::MaybeUninit::zeroed().assume_init()))
+    };
 
     let host = HostCallback::wrap(callback, effect);
     if host.vst_version() == 0 {

src/util/parameter_transfer.rs

@@ -181,6 +181,7 @@ mod tests {
         assert!(transfer.iterate(true).next().is_none());
 
         // Verify final values
+        #[allow(clippy::needless_range_loop)]
         for p in 0..PARAMETERS {
             assert!((0..THREADS).any(|t| (results[t][p] - values[p]).abs() < std::f32::EPSILON));
         }