diff --git a/core/src/avm1/globals/color.rs b/core/src/avm1/globals/color.rs
index f5deabe41..44eaa535a 100644
--- a/core/src/avm1/globals/color.rs
+++ b/core/src/avm1/globals/color.rs
@@ -139,7 +139,7 @@ fn set_rgb<'gc>(
         let [b, g, r, _] = rgb.to_le_bytes();
 
         let mut base = target.base_mut(activation.context.gc_context);
-        let mut color_transform = base.color_transform_mut();
+        let color_transform = base.color_transform_mut();
         color_transform.r_multiply = Fixed8::ZERO;
         color_transform.g_multiply = Fixed8::ZERO;
         color_transform.b_multiply = Fixed8::ZERO;
diff --git a/core/src/backend/audio/decoders.rs b/core/src/backend/audio/decoders.rs
index 8a5694d91..29da6ae4b 100644
--- a/core/src/backend/audio/decoders.rs
+++ b/core/src/backend/audio/decoders.rs
@@ -21,7 +21,7 @@ use thiserror::Error;
 
 #[derive(Debug, Error)]
 pub enum Error {
-    #[cfg(all(feature = "mp3"))]
+    #[cfg(feature = "mp3")]
     #[error("Couldn't decode MP3")]
     InvalidMp3(#[from] mp3::Error),
 
diff --git a/core/src/display_object.rs b/core/src/display_object.rs
index f58cf9528..e31ea588f 100644
--- a/core/src/display_object.rs
+++ b/core/src/display_object.rs
@@ -282,7 +282,7 @@ impl<'gc> DisplayObjectBase<'gc> {
         let sin_x = f64::sin(degrees.into_radians());
         let cos_y = f64::cos(degrees.into_radians() + self.skew);
         let sin_y = f64::sin(degrees.into_radians() + self.skew);
-        let mut matrix = &mut self.transform.matrix;
+        let matrix = &mut self.transform.matrix;
         matrix.a = (self.scale_x.unit() * cos_x) as f32;
         matrix.b = (self.scale_x.unit() * sin_x) as f32;
         matrix.c = (self.scale_y.unit() * -sin_y) as f32;
@@ -308,7 +308,7 @@ impl<'gc> DisplayObjectBase<'gc> {
 
         let cos = f64::cos(self.rotation.into_radians());
         let sin = f64::sin(self.rotation.into_radians());
-        let mut matrix = &mut self.transform.matrix;
+        let matrix = &mut self.transform.matrix;
         matrix.a = (cos * value.unit()) as f32;
         matrix.b = (sin * value.unit()) as f32;
     }
@@ -332,7 +332,7 @@ impl<'gc> DisplayObjectBase<'gc> {
 
         let cos = f64::cos(self.rotation.into_radians() + self.skew);
         let sin = f64::sin(self.rotation.into_radians() + self.skew);
-        let mut matrix = &mut self.transform.matrix;
+        let matrix = &mut self.transform.matrix;
         matrix.c = (-sin * value.unit()) as f32;
         matrix.d = (cos * value.unit()) as f32;
     }
diff --git a/core/src/display_object/container.rs b/core/src/display_object/container.rs
index 99f891a72..64e5289b1 100644
--- a/core/src/display_object/container.rs
+++ b/core/src/display_object/container.rs
@@ -848,7 +848,7 @@ impl<'gc> ChildContainer<'gc> {
                 .unwrap();
             self.render_list.remove(old_position);
 
-            if let Some((_, below_child)) = self.depth_list.range(..depth).rev().next() {
+            if let Some((_, below_child)) = self.depth_list.range(..depth).next_back() {
                 let new_position = self
                     .render_list
                     .iter()
diff --git a/core/src/display_object/edit_text.rs b/core/src/display_object/edit_text.rs
index 25bcb0d87..855cf8c9f 100644
--- a/core/src/display_object/edit_text.rs
+++ b/core/src/display_object/edit_text.rs
@@ -320,7 +320,7 @@ impl<'gc> EditText<'gc> {
         // Set position.
         {
             let mut base = text_field.base_mut(context.gc_context);
-            let mut matrix = base.matrix_mut();
+            let matrix = base.matrix_mut();
             matrix.tx = Twips::from_pixels(x);
             matrix.ty = Twips::from_pixels(y);
         }
diff --git a/core/src/display_object/video.rs b/core/src/display_object/video.rs
index 838cc9c82..ce0b0d2dd 100644
--- a/core/src/display_object/video.rs
+++ b/core/src/display_object/video.rs
@@ -18,7 +18,7 @@ use ruffle_render::quality::StageQuality;
 use ruffle_video::error::Error;
 use ruffle_video::frame::EncodedFrame;
 use ruffle_video::VideoStreamHandle;
-use std::borrow::{Borrow, BorrowMut};
+use std::borrow::BorrowMut;
 use std::cell::{Ref, RefMut};
 use std::collections::{BTreeMap, BTreeSet};
 use std::sync::Arc;
@@ -242,8 +242,7 @@ impl<'gc> Video<'gc> {
             let prev_keyframe_id = read
                 .keyframes
                 .range(..=frame_id)
-                .rev()
-                .next()
+                .next_back()
                 .copied()
                 .unwrap_or(0);
 
@@ -458,14 +457,14 @@ impl<'gc> TDisplayObject<'gc> for Video<'gc> {
     }
 
     fn id(&self) -> CharacterId {
-        match (*self.0.read().source.read()).borrow() {
+        match &*self.0.read().source.read() {
             VideoSource::Swf { streamdef, .. } => streamdef.id,
             VideoSource::NetStream { .. } => 0,
         }
     }
 
     fn self_bounds(&self) -> Rectangle<Twips> {
-        match (*self.0.read().source.read()).borrow() {
+        match &*self.0.read().source.read() {
             VideoSource::Swf { streamdef, .. } => Rectangle {
                 x_min: Twips::ZERO,
                 y_min: Twips::ZERO,