'onclick' type of 'this' is wrong

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
typescript
Domain
tooling

Research direction

Start by comparing the generated onclick declaration and its this type between TypeScript 3.0 and the 3.1.0-dev.20180804 output. Reproduce the fabric or tingle.js example, then verify that an onclick handler's this type exposes HTMLElement.innerHTML without causing the reported compile error.

Written by the indexing model from the issue text.

Description

bug 
document.body.onclick = function() {
    console.log(this.innerHTML.length);
}

The code works in a browser and worked in typescript@3.0. But in typescript@3.1.0-dev.20180804 it is a compile error:

src/a.ts:3:22 - error TS2339: Property 'innerHTML' does not exist on type 'GlobalEventHandlers'.

3     console.log(this.innerHTML.length);

The value of this should be HTMLElement like it was before, not GlobalEventHandlers.
Detected in fabric and tingle.js on DefinitelyTyped.

Dominant language
TypeScript
Stars
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Forks
474
Avg merge
2d 8h
Merged PRs (30d)
15

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