From c959443a8054b80d47909825f87a4da52a363965 Mon Sep 17 00:00:00 2001
From: Malte Ubl <malte@vercel.com>
Date: Tue, 27 Oct 2026 19:34:46 -0700
Subject: [PATCH] Exercise the unary island-call fix from the corpus program

The corpus case passed `new Swapper(tricky)` straight to `+`, which the
argument check already treated as effectful, so it never distinguished
the two lowerings. Bind the swapper to a local: an identifier is what
the old check called inert, and the program now prints "replaced
replaced" without the fix and matches Node with it. The class also used
a parameter property, which Node's strip-only mode rejects.

Co-Authored-By: Claude 5.5 <noreply@anthropic.com>
---
 tests/corpus/6816-node-island-objects/main.ts   | 17 ++++++++++++++---
 .../node_modules/islandkit/index.d.ts           |  2 +-
 .../node_modules/islandkit/index.js             |  5 ++---
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/tests/corpus/6816-node-island-objects/main.ts b/tests/corpus/6816-node-island-objects/main.ts
index 7a2724f8c..002613b33 100644
--- a/tests/corpus/6816-node-island-objects/main.ts
+++ b/tests/corpus/6816-node-island-objects/main.ts
@@ -3,7 +3,7 @@
 // require() specifier) runs in a Node island: its objects cross as
 // handles, so the same object returned twice is ===, and writes through
 // one reference are visible through every other, on both sides.
-import { Store, createStore, describe, VERSION, makePoint, addPoints, ping, makeTricky } from "islandkit";
+import { Store, createStore, describe, VERSION, makePoint, addPoints, ping, makeTricky, type Tricky } from "islandkit";
 import * as kit from "islandkit";
 
 console.log(VERSION);
@@ -35,10 +35,21 @@ console.log(p.x, p.y);
 p.x = 100;
 console.log(p.x + p.y);
 
-// JavaScript reads `tricky.method` before it evaluates `+tricky`, whose
+// JavaScript reads `tricky.method` before it evaluates `+swapper`, whose
 // valueOf replaces the method: the call must reach the original.
+class Swapper {
+  target: Tricky;
+  constructor(target: Tricky) {
+    this.target = target;
+  }
+  valueOf(): number {
+    this.target.method = this.target.other;
+    return 1;
+  }
+}
 const tricky = makeTricky();
-console.log("unary", tricky.method(+tricky), tricky.method(1));
+const swapper = new Swapper(tricky);
+console.log("unary", tricky.method(+swapper), tricky.method(1));
 
 console.log(ping(), ping(), kit.ping());
 
diff --git a/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.d.ts b/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.d.ts
index 360f0f783..7f1e9cf1c 100644
--- a/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.d.ts
+++ b/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.d.ts
@@ -26,6 +26,6 @@ export declare let loads: number;
 export declare function ping(): number;
 export interface Tricky {
   method(value: number): string;
-  valueOf(): number;
+  other(): string;
 }
 export declare function makeTricky(): Tricky;
diff --git a/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.js b/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.js
index 09334ef4d..613181936 100644
--- a/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.js
+++ b/tests/corpus/6816-node-island-objects/node_modules/islandkit/index.js
@@ -20,8 +20,7 @@ exports.makeTricky = () => ({
   method() {
     return "original";
   },
-  valueOf() {
-    this.method = () => "replaced";
-    return 1;
+  other() {
+    return "replaced";
   },
 });