In JSDoc @type is not a type declaration, which it is much more like type conversion.

[leecjson]

I don't kown whether its a bug or feature.

In Javascript, actually i need an error emit which other_props is not in Entity

In Typescript, entityB act just same as the Javascript codes above

[orta]

Here's a repro:

// filename: index.js
// @ts-check

/** @typedef Entity
 * @property {string} prop
 */

/**
 * @type {{[key in keyof Entitiy] : any }}
 */

const e = {
    prop: 1233,
    s: ""
}

Workbench Repro

[theGreen233]

Hello, we are a group of researchers developing machine learning techniques to locate issues suitable for newcomers, and our model considers this issue as likely a "good first issue". May we recommend you to label it as "good first issue" so newcomers know where to choose?

Thank you!

[typescript-bot]

👋 Hi, I'm the Repro bot. I can help narrow down and track compiler bugs across releases! This comment reflects the current state of this repro running against the nightly TypeScript.

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Comment by @orta

👍 Compiled

Historical Information

Version	Reproduction Outputs
4.2.2, 4.3.2, 4.4.2, 4.5.2, 4.6.2	👍 Compiled

[rubiesonthesky]

There is typo in @orta 's repro code as far as I can understand. Entity vs Entitiy

-  * @type {{[key in keyof Entitiy] : any }}
+  * @type {{[key in keyof Entity] : any }}