microsoft / microsoft/TypeScript

--noImplicitThis error is inconsistent

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#25,526 6 comments 1 reaction 0 assignees View on GitHub

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Bug Domain: This-Typing
Dominant language
Go
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Merged PRs (30d)
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Description

TypeScript Version: 3.0.0-dev.20180707

Code

declare function f(a: any): void;
f(function() {
	this.m();
});

f({
	callback: function() {
		this.m();
	}
});

Expected behavior:

With --noImplicitThis, errors in both cases or neither case.

Actual behavior:

Only error in the first case.

Contributor guide

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No source file or test is named. Start by running the provided TypeScript snippet with --noImplicitThis and trace how the compiler checks this inside the two callback forms. Done means both cases consistently produce an error or neither does, with regression coverage for the behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
42/100

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