René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Generic parameter types are incorrectly inferred as { }","articleBody":"\u003c!-- 🚨 STOP 🚨 𝗦𝗧𝗢𝗣 🚨 𝑺𝑻𝑶𝑷 🚨\r\n\r\nHalf of all issues filed here are duplicates, answered in the FAQ, or not appropriate for the bug tracker. Even if you think you've found a *bug*, please read the FAQ first, especially the Common \"Bugs\" That Aren't Bugs section!\r\n\r\nPlease help us by doing the following steps before logging an issue:\r\n  * Search: https://github.com/Microsoft/TypeScript/search?type=Issues\r\n  * Read the FAQ: https://github.com/Microsoft/TypeScript/wiki/FAQ\r\n\r\nPlease fill in the *entire* template below.\r\n--\u003e\r\n\r\n\u003c!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. --\u003e\r\n**TypeScript Version:**  3.0.1, vscode 1.26.1\r\n\r\n\u003c!-- Search terms you tried before logging this (so others can find this issue more easily) --\u003e\r\n**Search Terms:**\r\n\r\n**Code**\r\n\r\n```ts\r\ninterface A\u003cR\u003e {\r\n    a(): R\r\n}\r\n\r\nfunction some1\u003cR\u003e(a: A\u003cR\u003e): R {\r\n    return null\r\n}\r\n\r\nfunction some2\u003cR, D extends A\u003cR\u003e\u003e(a: D): R {\r\n    return null\r\n}\r\n\r\nlet out1 = some1({\r\n    a() {\r\n        return 'asd'\r\n    }\r\n})\r\n\r\nlet out2 = some2({\r\n    a() {\r\n        return 'asd'\r\n    }\r\n})\r\n```\r\n\r\n**Expected behavior:** out1: `string`, out2: `string`\r\n\r\n**Actual behavior:** out1: `string`, out2: `{}`\r\n\r\n[**Playground Link**](http://www.typescriptlang.org/play/index.html#src=interface%20A%3CR%3E%20%7B%0D%0A%20%20%20%20a()%3A%20R%0D%0A%7D%0D%0A%0D%0Afunction%20some1%3CR%3E(a%3A%20A%3CR%3E)%3A%20R%20%7B%0D%0A%20%20%20%20return%20null%0D%0A%7D%0D%0A%0D%0Afunction%20some2%3CR%2C%20D%20extends%20A%3CR%3E%3E(a%3A%20D)%3A%20R%20%7B%0D%0A%20%20%20%20return%20null%0D%0A%7D%0D%0A%0D%0Alet%20out1%20%3D%20some1(%7B%0D%0A%20%20%20%20a()%20%7B%0D%0A%20%20%20%20%20%20%20%20return%20'asd'%0D%0A%20%20%20%20%7D%0D%0A%7D)%0D%0A%0D%0Alet%20out2%20%3D%20some2(%7B%0D%0A%20%20%20%20a()%20%7B%0D%0A%20%20%20%20%20%20%20%20return%20'asd'%0D%0A%20%20%20%20%7D%0D%0A%7D)) \u003c!-- A link to a TypeScript Playground \"Share\" link which demonstrates this behavior --\u003e\r\n\r\n\u003c!-- **Related Issues:**   Did you find other bugs that looked similar? --\u003e\r\n\u003c!-- **Related Issues:**  \r\n[https://github.com/Microsoft/TypeScript/issues/26807](https://github.com/Microsoft/TypeScript/issues/26807)--\u003e","author":{"url":"https://github.com/2A5F","@type":"Person","name":"2A5F"},"datePublished":"2018-08-31T07:52:26.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/26809/TypeScript/issues/26809"}