Microsoft/TypeScript

Give better error messages when reserved names are used for binding identifiers

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#11,648 opened on Oct 14, 2016

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 (4 comments) (0 reactions) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
Domain: Error MessagesEffort: ModerateHelp WantedSuggestion

Description

const data = { in: 1 };
const { in } = data; // <-- [ts] ':' expected.

Contributor guide

Tech stack
typescript
Domain
developer experiencetooling
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.
1-3 hours
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 basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate how TypeScript's parser handles destructuring with reserved words like 'in'. Look in src/compiler/parser.ts for error reporting logic around binding identifiers. The error message currently says ':' expected when 'in' is used as a destructuring variable name. A better message should indicate that reserved words cannot be used as identifiers. Consider linking to similar error handling for other reserved words.