diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 9a84a8f..c117dc2 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -23,13 +23,16 @@ jobs:
             ~/.cargo/registry
             ~/.cargo/git
             target
-          key: ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain') }}-${{ hashFiles('Cargo.lock') }}
+          key: ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
           restore-keys: |
-            ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain') }}-${{ hashFiles('Cargo.lock') }}
-            ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain') }}-
+            ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain.toml') }}-${{ hashFiles('Cargo.lock') }}
+            ${{ github.job }}-${{ runner.os }}-${{ hashFiles('rust-toolchain.toml') }}-
 
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
+        # This installs the toolchain specified in `rust-toolchain.toml`.
+        # There's no need to set it as the default toolchain since all
+        # rustup shims respect the aforementioned toolchain file.
+        run: rustup install
 
       - name: Install just
         uses: taiki-e/install-action@just
diff --git a/rust-toolchain b/rust-toolchain
deleted file mode 100644
index f288d11..0000000
--- a/rust-toolchain
+++ /dev/null
@@ -1 +0,0 @@
-1.85.0
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..b475f2f
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,3 @@
+[toolchain]
+channel = "1.85.0"
+components = ["rustfmt", "clippy"]