From 3f05a5099efa329820564e5d717e2fe5b355e9bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Mon, 23 Mar 2026 20:51:45 +0100
Subject: [PATCH] Fix

---
 packages/effect-fc/src/Lens.ts | 38 ++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/packages/effect-fc/src/Lens.ts b/packages/effect-fc/src/Lens.ts
index a4c653b..ce7933c 100644
--- a/packages/effect-fc/src/Lens.ts
+++ b/packages/effect-fc/src/Lens.ts
@@ -79,7 +79,7 @@ export const map = <A, ER, RR, EW, RW, B>(
             (b: B): (parent: A) => A
             (parent: A, b: B): A
         },
-    }
+    },
 ): Lens<B, ER, RR, EW, RW> => make({
     get: Effect.map(self.get, options.get),
     changes: Stream.map(self.changes, options.get),
@@ -91,25 +91,37 @@ export const map = <A, ER, RR, EW, RW, B>(
             options.set.length >= 2
                 ? (options.set as (parent: A, b: B) => A)(a, next)
                 : (options.set as (b: B) => (parent: A) => A)(next)(a),
-        ] as const))
+        ]))
     ),
 })
 
 export const mapEffect = <A, ER, RR, EW, RW, B, EGet = never, RGet = never, ESet = never, RSet = never>(
     self: Lens<A, ER, RR, EW, RW>,
-    getF: (a: A) => Effect.Effect<B, EGet, RGet>,
-    setF: (b: B, parent: A) => Effect.Effect<A, ESet, RSet>,
+    options: {
+        readonly get: (a: A) => Effect.Effect<B, EGet, RGet>,
+        readonly set: {
+            (b: B): (parent: A) => Effect.Effect<A, ESet, RSet>
+            (parent: A, b: B): Effect.Effect<A, ESet, RSet>
+        },
+    },
 ): Lens<B, ER | EGet, RR | RGet, EW | ESet, RW | RSet> => {
-    const get = Effect.flatMap(self.get, getF)
-    const changes = Stream.mapEffect(self.changes, getF)
-    const modify = <C, E1 = never, R1 = never>(
-        h: (b: B) => Effect.Effect<readonly [C, B], E1, R1>
-    ) => self.modify((a: A) => Effect.flatMap(getF(a), b => Effect.flatMap(h(b), ([c, bNext]) => Effect.flatMap(setF(bNext, a), nextA => Effect.succeed([c, nextA] as const)))))
-
     return make({
-        get: Effect.flatMap(self.get, getF),
-        changes: Stream.mapEffect(self.changes, getF),
-        modify,
+        get: Effect.flatMap(self.get, options.get),
+        changes: Stream.mapEffect(self.changes, options.get),
+        modify: <C, E1 = never, R1 = never>(
+            f: (b: B) => Effect.Effect<readonly [C, B], E1, R1>
+        ) => self.modify(a => Effect.flatMap(
+            options.get(a),
+            b => Effect.flatMap(
+                f(b),
+                ([c, bNext]) => Effect.flatMap(
+                    options.set.length >= 2
+                        ? (options.set as (parent: A, b: B) => Effect.Effect<A, ESet, RSet>)(a, bNext)
+                        : (options.set as (b: B) => (parent: A) => Effect.Effect<A, ESet, RSet>)(bNext)(a),
+                    nextA => Effect.succeed([c, nextA] as const),
+                ),
+            )
+        )),
     })
 }