nested module works as-is with non-nested arrays

Plan to leverage this by refactoring the `nested` module into lib.rs,
thereby supporting both "flat" and nested arrays with same simple syntax

refs #2

src/nested.rs

@@ -50,12 +50,12 @@ impl<'a, T: Serialize, const N: usize> Serialize for ArrayWrap<'a, T, N> {
     }
 }
 
-pub trait NestedArray<T: Serialize, const N: usize> {
+pub trait SerializeArray<T: Serialize, const N: usize> {
     fn serialize<S>(&self, ser: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer;
 }
-impl<T: Serialize, const N: usize, const M: usize> NestedArray<T, N> for [[T; N]; M] {
+impl<T: Serialize, const N: usize, const M: usize> SerializeArray<T, N> for [[T; N]; M] {
     fn serialize<S>(&self, ser: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
@@ -70,7 +70,7 @@ impl<T: Serialize, const N: usize, const M: usize> NestedArray<T, N> for [[T; N]
         s.end()
     }
 }
-impl<T: Serialize, const N: usize> NestedArray<T, N> for Vec<[T; N]> {
+impl<T: Serialize, const N: usize> SerializeArray<T, N> for Vec<[T; N]> {
     fn serialize<S>(&self, ser: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
@@ -83,10 +83,18 @@ impl<T: Serialize, const N: usize> NestedArray<T, N> for Vec<[T; N]> {
         s.end()
     }
 }
+impl<T: Serialize, const N: usize> SerializeArray<T, N> for [T; N] {
+    fn serialize<S>(&self, ser: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        super::serialize(self, ser)
+    }
+}
 
 pub fn serialize<A, S, T, const N: usize>(data: &A, ser: S) -> Result<S::Ok, S::Error>
 where
-    A: NestedArray<T, N>,
+    A: SerializeArray<T, N>,
     S: Serializer,
     T: Serialize,
 {

tests/common/nested.rs

@@ -24,3 +24,9 @@ pub struct VecArray<const N: usize> {
     #[serde(with = "serde_arrays::nested")]
     pub arr: Vec<[u32; N]>,
 }
+
+#[derive(Serialize, Debug, PartialEq, Eq)]
+pub struct FlatArray<const N: usize> {
+    #[serde(with = "serde_arrays::nested")]
+    pub arr: [u32; N],
+}

tests/serialize_nested.rs

@@ -25,3 +25,10 @@ fn serialize_nested_array() {
     assert_eq!(json, &j_generic);
     assert_eq!(json, &j_vecced);
 }
+
+#[test]
+fn serialize_flat_as_nested() {
+    let flat = FlatArray { arr: [1; 3] };
+    let j_flat = serde_json::to_string(&flat).unwrap();
+    assert_eq!("{\"arr\":[1,1,1]}", &j_flat);
+}