From 9711ecc80d130be155b8b3018b968c2ba42c4b64 Mon Sep 17 00:00:00 2001
From: Cold Fry <coldfry.business@gmail.com>
Date: Tue, 14 Apr 2026 07:12:52 +0000
Subject: [PATCH 1/2] fix array destructuring not preserving evaluation order
 with side effects (#1405)

---
 src/transformation/visitors/variable-declaration.ts | 4 ++--
 test/unit/destructuring.spec.ts                     | 9 +++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/transformation/visitors/variable-declaration.ts b/src/transformation/visitors/variable-declaration.ts
index f15ed0115..61d50cad4 100644
--- a/src/transformation/visitors/variable-declaration.ts
+++ b/src/transformation/visitors/variable-declaration.ts
@@ -12,7 +12,7 @@ import { createCallableTable, isFunctionTypeWithProperties } from "./function";
 import { transformIdentifier } from "./identifier";
 import { isMultiReturnCall } from "./language-extensions/multi";
 import { transformPropertyName } from "./literal";
-import { moveToPrecedingTemp } from "./expression-list";
+import { moveToPrecedingTemp, transformExpressionList } from "./expression-list";
 
 export function transformArrayBindingElement(
     context: TransformationContext,
@@ -205,7 +205,7 @@ export function transformBindingVariableDeclaration(
             // Don't unpack array literals
             const values =
                 initializer.elements.length > 0
-                    ? initializer.elements.map(e => context.transformExpression(e))
+                    ? transformExpressionList(context, initializer.elements)
                     : lua.createNilLiteral();
             statements.push(...createLocalOrExportedOrGlobalDeclaration(context, vars, values, initializer));
         } else {
diff --git a/test/unit/destructuring.spec.ts b/test/unit/destructuring.spec.ts
index 65ecf95a3..b525e2cf8 100644
--- a/test/unit/destructuring.spec.ts
+++ b/test/unit/destructuring.spec.ts
@@ -226,6 +226,15 @@ describe("array destructuring optimization", () => {
             .expectToMatchJsResult();
     });
 
+    test("array literal with side effects in elements", () => {
+        util.testFunction`
+            const arr = [1, 2];
+            let i = 0;
+            let [v1, v2] = [arr[i], arr[++i]];
+            return { v1, v2 };
+        `.expectToMatchJsResult();
+    });
+
     test("array union", () => {
         util.testFunction`
             const array: [string] | [] = ["bar"];

From 556cd1f2027f1fbf3c377f29b3ff66f0dc1b53ad Mon Sep 17 00:00:00 2001
From: Cold Fry <coldfry.business@gmail.com>
Date: Tue, 14 Apr 2026 07:26:10 +0000
Subject: [PATCH 2/2] add more test cases for array destructuring side effects

---
 test/unit/destructuring.spec.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/unit/destructuring.spec.ts b/test/unit/destructuring.spec.ts
index b525e2cf8..4820876a4 100644
--- a/test/unit/destructuring.spec.ts
+++ b/test/unit/destructuring.spec.ts
@@ -235,6 +235,24 @@ describe("array destructuring optimization", () => {
         `.expectToMatchJsResult();
     });
 
+    test("array literal with many side effects in elements", () => {
+        util.testFunction`
+            const arr = [10, 20, 30, 40];
+            let i = 0;
+            let [v1, v2, v3, v4] = [arr[i++], arr[i++], arr[i++], arr[i++]];
+            return { v1, v2, v3, v4 };
+        `.expectToMatchJsResult();
+    });
+
+    test("array literal with mixed pure and impure elements", () => {
+        util.testFunction`
+            const arr = [10, 20, 30];
+            let i = 0;
+            let [v1, v2, v3] = [1, arr[++i], 2];
+            return { v1, v2, v3, i };
+        `.expectToMatchJsResult();
+    });
+
     test("array union", () => {
         util.testFunction`
             const array: [string] | [] = ["bar"];