Clippy: assign operators and is_multiple_of in the continuity code

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/geom/src/brep/normal_section.rs

@@ -82,7 +82,7 @@ fn nonlinear(d: &Partials, du: &Series<f64>, dv: &Series<f64>) -> Series<Vec3> {
         let term = times(&pu[i], &pv[j]);
         let weight = 1.0 / (factorial(i) * factorial(j));
         for (o, t) in out.iter_mut().zip(term) {
-            *o = *o + d[i][j] * (t * weight);
+            *o += d[i][j] * (t * weight);
         }
     }
     out

crates/geom/src/tess/partials.rs

@@ -134,7 +134,7 @@ fn nurbs_partials(degree: [usize; 2], knots: &[Vec<f64>; 2], count: [usize; 2],
             let l = total - k;
             let mut x = xyz(a[k][l]);
             for (i, j) in (0..=k).flat_map(|i| (0..=l).map(move |j| (i, j))).filter(|ij| *ij != (0, 0)) {
-                x = x - d[k - i][l - j] * (binomial(k, i) * binomial(l, j) * a[i][j][3]);
+                x -= d[k - i][l - j] * (binomial(k, i) * binomial(l, j) * a[i][j][3]);
             }
             d[k][l] = x * (1.0 / w);
         }
@@ -169,7 +169,7 @@ impl EvalCurve {
         for k in 0..=order {
             let mut x = xyz(*a.get(k)?);
             for i in 1..=k {
-                x = x - *d.get(k - i)? * (binomial(k, i) * a.get(i)?[3]);
+                x -= *d.get(k - i)? * (binomial(k, i) * a.get(i)?[3]);
             }
             d.push(x * (1.0 / w));
         }

crates/kernel/src/continuity.rs

@@ -429,7 +429,7 @@ fn station(at: Vec3, tangent: Vec3, on_a: &mut FaceSurface, on_b: &mut FaceSurfa
     // round, so its k-th derivative of curvature reads (−1)^(k+1) times as much in face a's.
     let opposed = na.dot(nb) < 0.0;
     let jump = |k: usize, a: f64, b: f64| {
-        let flip = if opposed && k % 2 == 0 { -1.0 } else { 1.0 };
+        let flip = if opposed && k.is_multiple_of(2) { -1.0 } else { 1.0 };
         (a - flip * b).abs()
     };
     let [ka, ca, ra] = ja.values();

crates/ui-egui/src/dialogs_surface.rs

@@ -1111,7 +1111,7 @@ mod tests {
             for g in Continuity::ALL {
                 let (label, tip) = (locale.text(g.label_id()), locale.text(g.tip_id()));
                 assert!(label != g.label_id() && tip != g.tip_id(), "{lang}: {g:?} has no text");
-                assert!(!coded(&label), "{lang}: the {g:?} label names a code: {label}");
+                assert!(!coded(label), "{lang}: the {g:?} label names a code: {label}");
                 assert!(tip.contains(g.code()), "{lang}: the {g:?} hover text names its code: {tip}");
             }
         }