Cannot 'export default' abstract, ambient class or interface

Description

export default abstract class B {

}

export default declare class B {

}

Contributor guide

Tech stack

typescript

Domain

tooling

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-2 days

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

TypeScript basicsparser knowledge

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

25

Research direction

Investigate the TypeScript parser source code, likely in src/parser.ts, to understand how export declarations are handled. Look for how abstract and declare modifiers are parsed. Check existing comments in the issue for any suggested fix approaches.