diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 7a52634..b10df3b 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -2,9 +2,9 @@ name: checks
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
   # allow manual trigger
   workflow_dispatch:
 
@@ -20,51 +20,22 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         rust:
+          - 1.63 # MSRV from Cargo.toml
           - 1.84.1 # pre edition2024
           - 1.87
           - stable
+          - nightly
     steps:
-    - uses: actions/checkout@v2
-
-    - uses: actions-rs/toolchain@v1
-      with:
-        profile: minimal
-        toolchain: ${{matrix.rust}}
-        override: true
-
-    - name: Build lib
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose
-    - name: Build examples
-      run: cargo build --example '*'
-
-  style:
-    name: Style checks for ${{matrix.rust}} on ${{matrix.os}}
-    runs-on: ${{matrix.os}}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        rust:
-          - 1.84.1 # pre edition2024
-          - 1.87   # clippy became more picky after this
-          - stable
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@v6
+      - uses: dtolnay/rust-toolchain@v1
         with:
-          profile: minimal
-          toolchain: ${{matrix.rust}}
-          override: true
           components: rustfmt, clippy
+          toolchain: ${{matrix.rust}}
+      - name: Build lib
+        run: cargo build --verbose --all-targets --all-features
+      - name: Run tests
+        run: cargo test --verbose
       - name: fmt
-        uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: --all -- --check
+        run: cargo fmt --all -- --check
       - name: clippy
-        uses: actions-rs/cargo@v1
-        with:
-          command: clippy
-          args: --all-targets --all-features -- -D warnings
+        run: cargo clippy --all-targets --all-features -- -D warnings
diff --git a/Cargo.toml b/Cargo.toml
index f1d99c1..012f09c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,7 @@ readme = "README.md"
 keywords = ["patch", "diff", "parse", "nom"]
 license = "MIT"
 edition = "2018"
+rust-version = "1.63" # matches .github/workflows/checks.yml
 
 [dependencies]
 nom = "7.1.0"
diff --git a/src/ast.rs b/src/ast.rs
index d923f10..48374c4 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -299,7 +299,7 @@ mod tests {
             range_hint: "",
             lines: vec![],
         };
-        for (input, expected) in vec![
+        for (input, expected) in [
             ("", None),
             (" ", None),
             ("  ", None),