A function referenced inside its own module is a different object from the same function imported elsewhere: `export function isSame(x){ return x === f }` returns false for the imported `f`

[proggeramlug]

Found by the package audit (while fixing #10434) on Perry 7661bc0 (v0.5.1587→v0.5.1589 baseline), Linux x64.
A module-level function f compared by identity inside its defining module is not === to the f value an importer
receives, although two importers' views agree with each other (ns.f === f is true in the importer).

Reproduction

lib/fns.ts:

function f() { return 1; }
export function isSame(x: unknown) { return x === f; }
export { f };

main.ts:

import { f, isSame } from "./lib/fns.ts";
import * as ns from "./lib/fns.ts";
console.log(isSame(f), isSame(ns.f), ns.f === f);

node main.ts
PERRY_NO_AUTO_OPTIMIZE=1 perry compile main.ts -o main && ./main

Expected (Node 26.5.1)

true true true

Actual (Perry)

false false true

Impact

Identity checks against a module's own exported functions are common: registries and caches keyed by function
(map.get(handler)), "is this our default implementation" checks (if (opts.serialize === defaultSerialize)),
removeEventListener/off(fn) with an exported listener, memoization keyed by function, and plugin dedup. With
Perry these silently take the wrong branch or fail to remove listeners.

Notes

• Reported by the fixer as caused by the cross-module inliner cloning small exported functions together with the
  functions they reference (so the clone's f is a different value). Not confirmed: in this repro the result is
  identical with PERRY_NO_INLINE=1 set, which may not be the right knob — check which transform/lowering gives the
  in-module reference to f a different value than the export slot (in-module direct reference vs exported wrapper
  closure __perry_wrap_*, or inlined clone).
• Related but distinct: function F(){}; export default F; exports a different function object: importers lose F's prototype methods and statics, and missing arguments arrive as garbage instead of undefined #10434 (export default F handed importers a wrapper instead of F), fixed by PR fix(hir): export default F exports the declared function's own binding #10548.