microsoft / microsoft/TypeScript
Invalid error on computed property name using a variable with the same name as a constructor parameter of that class
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Nobody has claimed this yet.
Bug
Domain: classes
- Dominant language
- Go
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Description
TypeScript Version: 4.1.3
Search Terms:
Expected behavior:
No error. The downlevel emit is fine, so this won't give any unexpected behavior at runtime.
Actual behavior:
Initializer of instance member variable '[a]' cannot reference identifier 'a' declared in the constructor.
Code
const a = Symbol();
class C {
[a] = 1;
constructor(a) {}
}
Output
"use strict";
var _a;
const a = Symbol();
class C {
constructor(a) {
this[_a] = 1;
}
}
_a = a;
Compiler Options
{
"compilerOptions": {
"noImplicitAny": true,
"strictNullChecks": true,
"strictFunctionTypes": true,
"strictPropertyInitialization": true,
"strictBindCallApply": true,
"noImplicitThis": true,
"noImplicitReturns": true,
"alwaysStrict": true,
"esModuleInterop": true,
"declaration": true,
"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"moduleResolution": 2,
"target": "ES2017",
"jsx": "React",
"module": "ESNext"
}
}
Playground Link: Provided
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the reported TypeScript 4.1.3 example with the supplied compiler options and compare the diagnostic with the emitted JavaScript. The issue is done when the computed property name using the outer variable produces no erroneous diagnostic while retaining the shown valid downlevel output.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 42/100