diff --git a/clippy.toml b/clippy.toml
new file mode 100644
index 00000000..4b6c79f5
--- /dev/null
+++ b/clippy.toml
@@ -0,0 +1,4 @@
+allow-unwrap-in-tests = true
+allow-expect-in-tests = true
+allow-panic-in-tests = true
+allow-indexing-slicing-in-tests = true
diff --git a/crates/path/src/fit.rs b/crates/path/src/fit.rs
index b9dbced1..337acc90 100644
--- a/crates/path/src/fit.rs
+++ b/crates/path/src/fit.rs
@@ -72,8 +72,7 @@ fn bern(t: f64) -> [f64; 4] {
 
 /// Solve the 2x2 normal equations for the handle lengths along the fixed tangents.
 fn generate(pts: &[Point], u: &[f64], t0: Vec2, t1: Vec2) -> CubicBez {
-    let p0 = pts[0];
-    let p3 = *pts.last().unwrap();
+    let (Some(&p0), Some(&p3)) = (pts.first(), pts.last()) else { return CubicBez::new(Point::ZERO, Point::ZERO, Point::ZERO, Point::ZERO) };
     let dir_in = -t1; // handle at the end points backwards
     let (mut c00, mut c01, mut c11, mut x0, mut x1) = (0.0, 0.0, 0.0, 0.0, 0.0);
     for (p, &t) in pts.iter().zip(u) {
diff --git a/crates/path/src/lib.rs b/crates/path/src/lib.rs
index 169a7428..249eb9fd 100644
--- a/crates/path/src/lib.rs
+++ b/crates/path/src/lib.rs
@@ -5,6 +5,8 @@
 //! pucker & bloat, zig zag, twist, wiggle, offset, merge) live in [`ops`]; curve-preserving booleans
 //! (for Merge Paths) in [`boolean`] and curve offsetting in [`offset`].
 
+#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
+
 pub mod boolean;
 pub mod feather;
 mod fit;
diff --git a/crates/path/src/ops.rs b/crates/path/src/ops.rs
index 33537ba0..ec6e1860 100644
--- a/crates/path/src/ops.rs
+++ b/crates/path/src/ops.rs
@@ -651,7 +651,8 @@ pub fn merge(paths: &[BezPath], mode: MergeMode) -> BezPath {
         MergeMode::Subtract => crate::boolean::boolean_n(&inputs, |m| m[0] && !m[1..].iter().any(|&b| b)),
         MergeMode::Intersect => crate::boolean::boolean_n(&inputs, |m| m.iter().all(|&b| b)),
         MergeMode::Exclude => crate::boolean::boolean_n(&inputs, |m| m.iter().filter(|&&b| b).count() % 2 == 1),
-        MergeMode::Merge => unreachable!(),
+        // Handled above (no boolean operation).
+        MergeMode::Merge => crate::boolean::boolean_n(&inputs, |m| m.iter().any(|&b| b)),
     }
 }
 
diff --git a/crates/raster/src/inpaint.rs b/crates/raster/src/inpaint.rs
index a4ae40ce..15bdaa0d 100644
--- a/crates/raster/src/inpaint.rs
+++ b/crates/raster/src/inpaint.rs
@@ -497,7 +497,7 @@ pub fn patch_fill(img: &Image, hole: &[bool], init: Option<&Image>, patch: usize
     // Pyramid: stop while the image is still a few patches across.
     let mut levels = vec![fine];
     while levels.len() < 6 {
-        let last = levels.last().expect("level");
+        let Some(last) = levels.last() else { break };
         if last.w.min(last.h) / 2 < patch * 4 || !last.hole.iter().any(|b| *b) {
             break;
         }
@@ -774,7 +774,11 @@ pub fn fill_sequence(input: &FillInput, o: &FillOpts, progress: &mut dyn FnMut(u
             out[t] = Some(img.clone());
         } else {
             // Warp the previous result here along the backward flow (t → t − 1).
-            let prev = out[t - 1].as_ref().expect("previous frame");
+            // Frames after `t0` are filled in order, so the previous one is set.
+            let Some(prev) = out[t - 1].as_ref() else {
+                out[t] = Some(patch_fill(img, left, None, o.patch, o.seed));
+                continue;
+            };
             let mut warped = img.clone();
             for i in 0..w * h {
                 if left[i] {
diff --git a/crates/raster/src/lib.rs b/crates/raster/src/lib.rs
index f3e64695..f1760282 100644
--- a/crates/raster/src/lib.rs
+++ b/crates/raster/src/lib.rs
@@ -3,6 +3,8 @@
 //! [`Image`] stores premultiplied RGBA in `f32` (values may exceed 1.0 in 32 bpc projects). Every
 //! heavy operation is row-parallel with rayon.
 
+#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
+
 pub mod blur;
 pub mod channels3d;
 pub mod cuts;