Fix nightly build

.github/workflows/build.yml

@@ -18,7 +18,6 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.56
           - stable
           - nightly
         os:
@@ -27,6 +26,7 @@ jobs:
         exclude:
           - rust: nightly
             os: windows-latest
+      fail-fast: false
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -46,6 +46,22 @@ jobs:
         if: matrix.rust == 'nightly'
         run: cargo check --all-targets
 
+  msrv:
+    name: Build MSRV
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Install Rust
+        run: rustup default 1.56
+
+      - uses: Swatinem/rust-cache@v2
+
+      - name: Build
+        run: cargo build
+
   build-documentation:
     name: Build documentation
     runs-on: ubuntu-latest

Cargo.toml

@@ -17,6 +17,7 @@ keywords = ["random", "text", "markov", "typography"]
 categories = ["text-processing"]
 license = "MIT"
 edition = "2021"
+rust-version = "1.56"
 
 [dependencies]
 rand = {version = "0.8.5", default-features = false, features = ["alloc"]}

src/lib.rs

@@ -96,7 +96,7 @@ impl<'a> MarkovChain<'a> {
         let words = sentence.split_whitespace().collect::<Vec<&str>>();
         for window in words.windows(3) {
             let (a, b, c) = (window[0], window[1], window[2]);
-            self.map.entry((a, b)).or_insert_with(Vec::new).push(c);
+            self.map.entry((a, b)).or_default().push(c);
         }
         // Sync the keys with the current map.
         self.keys = self.map.keys().cloned().collect();
@@ -556,8 +556,7 @@ pub fn lipsum_title() -> String {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use rand::{thread_rng, SeedableRng};
-    use rand_chacha::ChaCha20Rng;
+    use rand::thread_rng;
 
     #[test]
     fn starts_with_lorem_ipsum() {