ci,contrib: check unused deps via cargo-machete

.github/workflows/ci.yaml

@@ -37,6 +37,9 @@ jobs:
       - name: Rustdoc
         run: cargo doc --workspace --no-deps
 
+      - name: Unused dependencies
+        uses: bnjbvr/cargo-machete@v0.7.0
+
       - name: Typos
         uses: crate-ci/typos@v1.26.0
 

contrib/pre-commit

@@ -1,5 +1,9 @@
 #!/usr/bin/env bash
 set -euo pipefail
-typos
 cargo fmt -- --check
 fd -e nix | xargs nixfmt --check
+if ! out="$(cargo machete 2>/dev/null)"; then
+    echo "$out"
+    exit 1
+fi
+typos