Map/Set's for...of loop doesn't work for class instance field

[codehz]

What happened

I found Map/Set inside class instance field doesn't work in for...of loop

What you expected

It should works like module level Map/Set do

Minimal reproduction

/**
 * Minimal reproduction for Perry bug:
 * `for...of` loop body is silently skipped when the iterable is a class instance field Map or Set.
 *
 * Tested with: ~/Projects/perry/target/release/perry (latest local build)
 * Reproduces with: perry test_minimal_repro.ts && ./test_minimal_repro
 *
 * Expected output (Bun / Node.js):
 *   class Map size: 2
 *   class Map for...of:
 *     entry 1 -> a
 *     entry 2 -> b       <-- Perry: MISSING
 *   class Set size: 2
 *   class Set for...of:
 *     elem x             <-- Perry: MISSING
 *     elem y             <-- Perry: MISSING
 *   module-level Map (works in Perry):
 *     entry 1 -> x
 *     entry 2 -> y
 *
 * Actual Perry output:
 *   class Map size: 2
 *   class Map for...of:       <-- loop body never executes
 *   class Set size: 2
 *   class Set for...of:       <-- loop body never executes
 *   module-level Map (works in Perry):
 *     entry 1 -> x
 *     entry 2 -> y
 *
 * Notes:
 *   - .size, .get(), .has(), .set(), .add(), .clear() all work correctly on class field Map/Set
 *   - for...of on class field Array works correctly
 *   - for...of on module-level Map/Set works correctly
 *   - Affects both `private` and `public` class fields
 *   - Affects both same-file and imported classes
 */

class Example {
  public classMap: Map<number, string> = new Map();
  public classSet: Set<string> = new Set();

  run(): void {
    this.classMap.set(1, "a");
    this.classMap.set(2, "b");
    this.classSet.add("x");
    this.classSet.add("y");

    // .size works correctly
    console.log("class Map size:", this.classMap.size); // 2 ✓
    console.log("class Map for...of:");
    for (const [k, v] of this.classMap) {
      console.log("  entry", k, "->", v); // Perry: never printed ✗
    }

    console.log("class Set size:", this.classSet.size); // 2 ✓
    console.log("class Set for...of:");
    for (const v of this.classSet) {
      console.log("  elem", v); // Perry: never printed ✗
    }
  }
}

new Example().run();

// Module-level Map/Set: for...of works correctly in Perry
const m = new Map<number, string>([
  [1, "x"],
  [2, "y"],
]);
console.log("module-level Map (works in Perry):");
for (const [k, v] of m) {
  console.log("  entry", k, "->", v); // Perry: works ✓
}

Command you ran:

perry test.ts && ./test

Environment

• Perry version: 0.5.386
• Host OS: ArchLinux
• Target: native
• Rust toolchain (if building from source): rustc 1.95.0 (59807616e 2026-04-14)
• Installed via: from source

Diagnostic output

Perry Doctor

Environment Checks
──────────────────
  ✓ perry version: 0.5.386
  ✓ update status: up to date
  ✓ clang (LLVM codegen): clang version 22.1.3
  ✓ system linker (cc): cc (GCC) 15.2.1 20260209
  ✓ runtime library: /home/codehz/Projects/perry/target/release/libperry_runtime.a
  ⚠ project config (perry.toml): not found - run: perry init

All critical checks passed with some warnings.

Anything else

I found it in my ecs demo, it hit infinite loop, so I create a minimal repro it using AI