Address Clippy lints

graphics/src/widget/canvas/path.rs

@@ -74,7 +74,7 @@ impl Path {
 pub(super) fn dashed(path: &Path, line_dash: LineDash<'_>) -> Path {
     Path::new(|builder| {
         let segments_odd = (line_dash.segments.len() % 2 == 1).then(|| {
-            [&line_dash.segments[..], &line_dash.segments[..]].concat()
+            [line_dash.segments, line_dash.segments].concat()
         });
 
         let mut draw_line = false;
@@ -103,8 +103,7 @@ pub(super) fn dashed(path: &Path, line_dash: LineDash<'_>) -> Path {
                 },
                 index: line_dash.offset,
                 intervals: segments_odd
-                    .as_ref()
-                    .map(Vec::as_slice)
+                    .as_deref()
                     .unwrap_or(line_dash.segments),
             },
         );

graphics/src/widget/canvas/path/builder.rs

@@ -53,7 +53,7 @@ impl Builder {
             let _ = self.raw.line_to(a);
         }
 
-        let _ = self.raw.arc_to(
+        self.raw.arc_to(
             math::Vector::new(radius, radius),
             math::Angle::radians(0.0),
             path::ArcFlags::default(),

graphics/src/widget/qr_code.rs

@@ -67,10 +67,7 @@ where
         let side_length = (self.state.width + 2 * QUIET_ZONE) as f32
             * f32::from(self.cell_size);
 
-        layout::Node::new(Size::new(
-            f32::from(side_length),
-            f32::from(side_length),
-        ))
+        layout::Node::new(Size::new(side_length, side_length))
     }
 
     fn draw(