René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Inference breaks when a function returns a tuple with another function","articleBody":"# Bug Report\r\n\r\n### 🔎 Search Terms\r\n\r\nInference, tuple, generic, callback, higher-order function\r\n\r\n### 🕗 Version \u0026 Regression Information\r\n\r\nv4.3.2 and below (tested down to v3.3.3)\r\n\r\n### ⏯ Playground Link\r\n\r\n[Playground link with relevant code](https://www.typescriptlang.org/play?#code/PTAEEkDsDMFMCdaQMa1AI0QQwNYGdQB3ACyVGgFcUAXASwHtJRFqL5IDWAHAGzUNrVioLJHpCE5KsjqMAUHIAmsZDyyIpNBkywAKAJQAuUAG05oUAB4AKgD5d6gObHr+0AF5boa3IC6C5VV1NEotRgwbABpQAFV7LABGF2isACZjEwcXN09Y3yNYhXRdBOiTPX0TAAZffNAQZlhWdgJICgBbdAQUglgADy4ValhFOWLSkQM3BpY2DlAqHDFCJl1+wZkRkVA2zoR9OSA)\r\n\r\n### 💻 Code\r\n\r\n```ts\r\ndeclare function a(): [\r\n  \u003cT\u003e(arg: T) =\u003e T\r\n]\r\n\r\ndeclare function b\u003cT, U\u003e(a1: T, a2: [(a: T) =\u003e U]): U\r\n\r\nb(1, [a()[0]]) // returns number, as expected\r\nb(1, a()) // returns unknown (expected a number)\r\n```\r\n","author":{"url":"https://github.com/vitalyq","@type":"Person","name":"vitalyq"},"datePublished":"2021-06-07T06:29:54.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/44476/TypeScript/issues/44476"}