diff --git a/packages/effect-fc/src/Lens.ts b/packages/effect-fc/src/Lens.ts
index f7f98c6..1c1fb62 100644
--- a/packages/effect-fc/src/Lens.ts
+++ b/packages/effect-fc/src/Lens.ts
@@ -155,10 +155,17 @@ export const mapStructAt: {
 ))
 
 export const mapArrayAt: {
+    <A, ER, EW, RR, RW>(
+        self: Lens<A[], ER, EW, RR, RW>,
+        index: number,
+    ): Lens<A, ER | NoSuchElementException, EW | NoSuchElementException, RR, RW>
     <A, ER, EW, RR, RW>(
         self: Lens<readonly A[], ER, EW, RR, RW>,
         index: number,
     ): Lens<A, ER | NoSuchElementException, EW | NoSuchElementException, RR, RW>
+    <A, ER, EW, RR, RW>(
+        index: number
+    ): (self: Lens<A[], ER, EW, RR, RW>) => Lens<A, ER | NoSuchElementException, EW | NoSuchElementException, RR, RW>
     <A, ER, EW, RR, RW>(
         index: number
     ): (self: Lens<readonly A[], ER, EW, RR, RW>) => Lens<A, ER | NoSuchElementException, EW | NoSuchElementException, RR, RW>
@@ -289,8 +296,8 @@ export const updateAndGetEffect: {
 
 Effect.gen(function*() {
     const ref = yield* SubscriptionRef.make({
-        values: [13, 69, 1488]
-    })
+        values: [13, 69, 1488] as readonly number[]
+    } as const)
 
     const myValueLens = ref.pipe(
         fromSubscriptionRef,
@@ -298,6 +305,8 @@ Effect.gen(function*() {
         mapArrayAt(1),
     )
 
+    const myValueLens2 = mapArrayAt(mapStructAt(fromSubscriptionRef(ref), "values"), 1)
+
     console.log(yield* ref.get, yield* myValueLens.get)
     yield* set(myValueLens, 22)
     console.log(yield* ref.get, yield* myValueLens.get)