diff --git a/.changeset/fair-buttons-sell.md b/.changeset/fair-buttons-sell.md
new file mode 100644
index 0000000..aee1817
--- /dev/null
+++ b/.changeset/fair-buttons-sell.md
@@ -0,0 +1,5 @@
+---
+'@rekajs/core': patch
+---
+
+Fix assignment op on member expressions
diff --git a/packages/core/src/expression.ts b/packages/core/src/expression.ts
index 6eef3f1..b004d37 100644
--- a/packages/core/src/expression.ts
+++ b/packages/core/src/expression.ts
@@ -64,7 +64,7 @@ const updateLocalValue = (
   let targetValue = baseValue;
 
   for (let i = 1; i < path.length - 1; i++) {
-    targetValue = baseValue[path[i]];
+    targetValue = targetValue[path[i]];
   }
 
   targetValue[path[path.length - 1]] = newValue;