microsoft / microsoft/TypeScript
strictPropertyInitialization should consider `return`
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Experience Enhancement
Suggestion
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Description
TypeScript Version: 3.2.0-dev.20181004
Code
class C {
x: number;
constructor(b: boolean) {
if (b) {
this.x = 3;
} else {
return new C(true);
}
}
}
Expected behavior:
No error.
Actual behavior:
src/a.ts:2:5 - error TS2564: Property 'x' has no initializer and is not definitely assigned in the constructor.
2 x: number;
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
Start with the TypeScript example and the strictPropertyInitialization diagnostic for property x. Trace the constructor control-flow analysis that handles return statements, then verify the example produces no TS2564 error when the return path creates a new C.
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
- Mostly clear
- Newbie friendliness
- 35/100