add lint workflow

.github/matchers/rust.json

@@ -0,0 +1,44 @@
+{
+    "problemMatcher": [
+        {
+            "owner": "cargo-common",
+            "pattern": [
+                {
+                    "regexp": "^(warning|warn|error)(\\[(\\S*)\\])?: (.*)$",
+                    "severity": 1,
+                    "message": 4,
+                    "code": 3
+                },
+                {
+                    "regexp": "^\\s+-->\\s(\\S+):(\\d+):(\\d+)$",
+                    "file": 1,
+                    "line": 2,
+                    "column": 3
+                }
+            ]
+        },
+        {
+            "owner": "cargo-test",
+            "pattern": [
+                {
+                    "regexp": "^.*panicked\\s+at\\s+'(.*)',\\s+(.*):(\\d+):(\\d+)$",
+                    "message": 1,
+                    "file": 2,
+                    "line": 3,
+                    "column": 4
+                }
+            ]
+        },
+        {
+            "owner": "cargo-fmt",
+            "pattern": [
+                {
+                    "regexp": "^(Diff in (\\S+)) at line (\\d+):",
+                    "message": 1,
+                    "file": 2,
+                    "line": 3
+                }
+            ]
+        }
+    ]
+}

.github/workflows/lint.yml

@@ -0,0 +1,51 @@
+# Copied from Twilight's Lint workflow.
+#
+# https://github.com/twilight-rs/twilight/blob/trunk/.github/workflows/lint.yml
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - name: Install toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: clippy
+
+      - name: Add problem matchers
+        run: echo "::add-matcher::.github/matchers/rust.json"
+
+      - name: Cache
+        uses: Swatinem/rust-cache@v2
+
+      - name: Run clippy
+        run: cargo clippy --tests -- -D warnings
+
+  rustfmt:
+    name: Format
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - name: Install toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rustfmt
+
+      - name: Add problem matchers
+        run: echo "::add-matcher::.github/matchers/rust.json"
+
+      - name: Cache
+        uses: Swatinem/rust-cache@v2
+
+      - name: Run cargo fmt
+        run: cargo fmt --all -- --check