microsoft / microsoft/TypeScript

JS typedef merged with default modified class errors strangely

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Bug Domain: Error Messages Domain: JavaScript
Dominant language
Go
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Avg merge
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Merged PRs (30d)
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Description

TypeScript Version: 3.4.0-dev.201xxxxx

Search Terms:

Code

export default class C {};
/**
 * @typedef {string | number} default
 */

Expected behavior:
An coherent error on attempting to merge a class and a typedef.

Actual behavior:

Duplicate identifier 'default'.

and

Duplicate identifier 'C'.

on the default type alias and class C, respectively.

cc @sandersn

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Research direction

No source files or tests are named. Start by reproducing the supplied JavaScript and JSDoc typedef with the referenced TypeScript 3.4 development version, then trace how the compiler reports the class and typedef merge. Done means the invalid merge produces one coherent diagnostic rather than the reported duplicate identifiers.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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