Impl arbitrary::Arbitrary for Array

Support for creating arbitrary arrays using rust-fuzz's `arbitrary`
crate, which is useful for randomized testing

Author: tarcieri

.github/workflows/hybrid-array.yml

@@ -38,7 +38,6 @@ jobs:
           targets: ${{ matrix.target }}
       - uses: RustCrypto/actions/cargo-hack-install@master
       - run: cargo hack build --target ${{ matrix.target }} --feature-powerset --optional-deps bytemuck,serde,subtle,zeroize
-      - run: cargo build --all-features --release
 
   careful:
     runs-on: ubuntu-latest
@@ -106,5 +105,5 @@ jobs:
         with:
           toolchain: ${{ matrix.toolchain }}
       - uses: RustCrypto/actions/cargo-hack-install@master
-      - run: cargo hack test --feature-powerset --optional-deps bytemuck,serde,subtle,zeroize
+      - run: cargo hack test --feature-powerset --optional-deps arbitrary,bytemuck,serde,subtle,zeroize
       - run: cargo test --all-features --release

Cargo.lock

@@ -20,6 +20,7 @@ rust-version = "1.85"
 typenum = { version = "1.17", features = ["const-generics"] }
 
 # optional dependencies
+arbitrary = { version = "1", optional = true }
 bytemuck = { version = "1", optional = true, default-features = false }
 serde = { version = "1", optional = true, default-features = false }
 subtle = { version = "2", optional = true, default-features = false, features = ["const-generics"] }

Cargo.toml

@@ -145,6 +145,9 @@ use core::{
 };
 use typenum::{Diff, Sum};
 
+#[cfg(feature = "arbitrary")]
+use arbitrary::Arbitrary;
+
 #[cfg(feature = "bytemuck")]
 use bytemuck::{Pod, Zeroable};
 
@@ -1028,6 +1031,17 @@ where
     }
 }
 
+#[cfg(feature = "arbitrary")]
+impl<'a, T, U> Arbitrary<'a> for Array<T, U>
+where
+    T: Arbitrary<'a>,
+    U: ArraySize,
+{
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        Self::try_from_fn(|_n| Arbitrary::arbitrary(u))
+    }
+}
+
 #[cfg(feature = "bytemuck")]
 unsafe impl<T, U> Pod for Array<T, U>
 where