Microsoft/TypeScript

Inconsistent behavior of "export as" symbols.

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#30,223 opened on Mar 5, 2019

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 (6 comments) (0 reactions) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
BugDomain: Error MessagesHelp Wanted

Description

TypeScript Version: 3.4.0-dev.20190305

Search Terms: export alias

Code

This is file of some-lib:

export { LongNameOfInnerClass as PublicNameClass } from './long-name-of-inner-class';

This is other file, that import above lib:

import { PublicNameClass } from 'some-lib';

new PublicNameClass(); // Here hints is OK

new PublicNameClass(wrongArgument); // Error ref to LongNameOfInnerClass

Expected behavior: TypeScript hints have same "export as" aliases for working code and for errors.

Actual behavior: TypeScript hints for the working code are different from the hints for errors.

Related Issues: Not sure, but it seems that this issue has a similar problem: symbolToName does handle exports of namespaces

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.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 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 fundamentalscompiler concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the symbol resolution logic in the TypeScript compiler, specifically in the binder or checker. Look at how exported aliases are handled in error messages vs. completions. The related issue #29459 may provide clues. Check files like src/compiler/binder.ts and src/compiler/checker.ts for symbol name handling.