Bug 255396

Problem is observed with emscripten build. 

Generated Module looks in this way:

// Module.mjs
var Module = (() => {
	var _scriptDir = import.meta.url;

	return (
		async function(Module = {})  {
			console.log(Module) // result is null, expected value is data

			var Module = typeof Module != "undefined" ? Module : {};

			console.log(Module) // result is {}

			// emscripten stuff
		}
	);
})();

export default Module;

After import like this:

// index.mjs
let factory = (await import("Module.mjs")).default
await Module({/* data */})

Something is got wrong and Module value is lost.