Repository navigation
A shadowed variable is generated in a an async function with a default parameter declared as a static property of a class when targeting ES5. #57897
Description
🔎 Search Terms
"shadowed", "shadowed variable", "generator"
🕗 Version & Regression Information
- This changed in commit or PR Move complex parameter lists of async function into downlevel generator body #56296
⏯ Playground Link
💻 Code
class X {
public static a = async (someVar: boolean = true) => {
return await X.b();
};
public static b = async () => {
return "GOOD";
};
}
declare class process {
static exit(code: number): never;
}
X.a()
.then(console.log)
.catch(() => {
console.error("BAD");
process.exit(1);
});🙁 Actual behavior
Between TS v5.4.2 and TS v5.3.3, the generated code from the above code sample changes to shadow the _a variable in the outer closure. See diff below:
var X = /** @class */ (function () {
function X() {
}
var _a;
_a = X;
- X.a = function (someVar) {
- if (someVar === void 0) { someVar = true; }
- return __awaiter(_a, void 0, void 0, function () {
- return __generator(_a, function (_b) {
- switch (_b.label) {
+ X.a = function () {
+ var args_1 = [];
+ for (var _i = 0; _i < arguments.length; _i++) {
+ args_1[_i] = arguments[_i];
+ }
+ return __awaiter(_a, __spreadArray([], args_1, true), void 0, function (someVar) {
+ if (someVar === void 0) { someVar = true; }
+ return __generator(_a, function (_a) {
+ switch (_a.label) {
case 0: return [4 /*yield*/, _a.b()];
- case 1: return [2 /*return*/, _b.sent()];
+ case 1: return [2 /*return*/, _a.sent()];
}
});
});
};
X.b = function () { return __awaiter(_a, void 0, void 0, function () {
return __generator(_a, function (_b) {
return [2 /*return*/, "GOOD"];
});
}); };
return X;
}());
X.a()
.then(console.log)
.catch(function () {
console.error("BAD");
process.exit(1);
});
Note that helpers have been omitted from this code sample.
Notice that in the context of the function, the class/function X is assigned to a variable _a in the "ambient" context of the class. In TS v5.3.3, the async state machine's state variable is declared as _b, but in TS v.5.4.2 is appears as if the context is lost when the state machine is generated, so the state is declared as _a, shadowing the earlier-declared _a.
🙂 Expected behavior
Expected that the async state machine's state variable does not shadow another variable.
Additional information about the issue
No response
This issue was found by Liaoliang Ye (@ipip2005).
Activity
DanielRosenwasser commentedon Mar 28, 2024
jakebailey commentedon Mar 29, 2024
iclanton commentedon Apr 22, 2024
jakebailey commentedon Apr 22, 2024
cheit-epic commentedon May 2, 2024
Our organization encountered this during our upgrade to 5.4.4. It was enough to consider reverting back to 5.2, but ultimately we ended up working around it by moving the static functions to be top-level functions instead.