Microsoft/TypeScript

Better error for semicolon after decorator

Open

#21,050 opened on Jan 6, 2018

View on GitHub
 (1 comment) (7 reactions) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
Domain: Error MessagesHelp WantedSuggestion

Description

TypeScript Version: 2.7.0-dev.20171230

Code

import { component } from "babyioc";

import { Member } from "./Effects";

class Example {
    @component(Member);
    public readonly member: Member;
}

Expected behavior:

file.ts(6,23): error TSXXXX: Semicolons not allowed after decorators.

Actual behavior:

file.ts(6,23): error TS1146: Declaration expected.

Not very important IMO, but a little confusing.

Contributor guide

Tech stack
typescript
Domain
developer experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
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
None
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
The error message 'Declaration expected' is generated by the parser when a semicolon is encountered after a decorator. To fix, locate the parser logic that handles decorators and add a specific check for semicolons, emitting a clearer error like 'Semicolons not allowed after decorators.' The change should be in the parser file, possibly around decorator parsing, and the new error message needs to be added to the diagnostic messages list.