microsoft / microsoft/TypeScript

"Did you mean parent object or child property?" in error messsages

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Domain: Error Messages Effort: Moderate Experience Enhancement Help Wanted Suggestion
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Description

Discussed with @RyanCavanaugh from his personal dev experience.

It's common to get an error message when accidentally using an inner property of an object. Similarly, we might forget to actually fetch an inner property of an object.

// @strict: true

interface Person {
  residence: House;
}

interface House {
  isHouseOfPain: boolean;
}

declare let home: House;
declare let person: Person;

   home = person.residence.isHouseOfPain;
// ~~~~
// error: Type 'boolean' is not assignable to type 'House'.

   home = person;
// ~~~~
// error: Property 'isHouseOfPain' is missing in type 'Person' but required in type 'House'.
//   related: 'isHouseOfPain' is declared here.

It'd be nice if we could hint to the user "hey, you might have dotted too far into this object" or "hey, did you mean to grab the residence property?"

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First steps

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  4. Open a pull request that references the issue number.

Research direction

No files or tests are named. Start by reproducing the two strict-mode examples in the issue and tracing the TypeScript checker diagnostics they produce. Done means the relevant errors can provide a useful hint about selecting a parent property or accessing a child property, with behavior covered by appropriate tests.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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