microsoft / microsoft/TypeScript
TypeScript fails to detect self-reference issue in "Parameter Properties" of constructors
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Description
### 🔎 Search Terms
* private property self reference
* private property self reference constructor
* Parameter Properties constructor self reference
### 🕗 Version & Regression Information
- This is reproducible at least between v4.9.5 and nightly -- I have not tried earlier versions
### ⏯ Playground Link
https://www.typescriptlang.org/play/?target=9&module=1&ts=5.9.2#code/JYWwDg9gTgLgBAbzgKwsAdnAhgZzgfQDM4BfOQqCEOAcnQgBMBTALjCxgAsaBuAKD5YARjhhQsAY3gSANrjwBZAJ4BhOThwAhXE0QC4BuAHojcLsDwB3YDJlwJWAK45dFnI9eYA5gAoAlACEfIb2EOiiUI5S0HA+YFDAAG4cuoQsZkpgTBDERHAAvOR+eiEk+oZesQB0NVhQXjjpERheANoAusUIwSGGUEwwjlCY5jhVhD41VXUNfvylAj0GRgBUxqajcAwQTHj08JbQANYANHCcEJZMiUxQS3AgSgBijpg+aRlZOQTEhYRd9xCEzm9xIKyMfDKAlk8jgADkmJY1LCmAAPGBMdAMRSqdRaHQlQyoDDVWr1RpwZroNqdQm9MycCxVXxTGY4EELKESMKiewFODoRHwxHIjT+fjc8IQGRMKoyCC+CRVYnoHw0LA0M40ISa2gSGh+OZwIA
### 💻 Code
```ts
import { join as _f } from 'node:path';
abstract class MyClassBase {
// this will cause issue in g()!
constructor (private f: typeof _f = f) {
}
g (...args: string[]) {
return this.f(...args);
}
/* // this does not work, however
myFun (f: typeof _f = f) {
f();
}*/
}
class NewClass extends MyClassBase {
join (...args: string[]) {
this.g(...args);
}
}
const c = new NewClass();
console.log(c.join('a', 'b', 'c'));
```
### 🙁 Actual behavior
TypeScript compiler does not report any errors.
if you copy transpiled JS file and run that with Node.js, you will see
```
constructor(f = f) {
^
ReferenceError: Cannot access 'f' before initialization
```
### 🙂 Expected behavior
TypeScript clearly shows an error, similar to what would have been seen in regular function parameters
```
Parameter 'f' cannot reference itself.
```
### Additional information about the issue
The issue originated from this -- https://github.com/microsoft/vscode-js-debug-browsers/issues/19, and I just discovered that the issue in the project or TypeScript has never been fixed. If someone at Microsoft could do a favor and ping the maintainer of that repo as well, it will be much appreciated.
Guide de contribution
Ouvrir le guide de contribution
Piste de recherche
Commencez par la reproduction liée dans Playground et par le traitement par le compilateur des propriétés de paramètres du constructeur, en le comparant aux vérifications d’autoréférence des paramètres de fonction ordinaires. Confirmez l’échec du JavaScript généré et ajoutez une couverture au compilateur afin que le cas du constructeur signale une erreur telle que « Parameter 'f' cannot reference itself. »
Rédigé par le modèle d'indexation à partir du texte de l'issue.
Évaluation
- Stack technique
- typescript
- Domaine
- compilers
- Type d'issue
- Bug
- Difficulté
- 4/5
- Temps estimé
- 3-5 jours
- Activité
- À l'abandon
- Clarté
- Plutôt claire
- Accessibilité débutants
- 35/100