René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Arrow functions treated differently than functions and methods","articleBody":"\u003c!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. --\u003e\r\n**TypeScript Version:**  3.2.2 and 3.3.0-dev.20190119\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:** arrow function method object literal\r\n\r\n**Code**\r\n\r\n```ts\r\ntype Test\u003cK extends keyof any\u003e = {\r\n  [P in K | \"foo\"]: P extends \"foo\" ? true : () =\u003e any\r\n}\r\n\r\nfunction test\u003cT extends Test\u003ckeyof T\u003e\u003e(arg: T) {\r\n    return arg;\r\n}\r\n\r\nconst res1 = test({\r\n  foo: true,\r\n  bar() {\r\n    // Notice the type param of `test` is inferred as `Test\u003cnever\u003e`\r\n  }\r\n})\r\n\r\nconst res2 = test({\r\n  foo: true,\r\n  bar: function () {\r\n    // Same error here.\r\n  }\r\n})\r\n\r\nconst res3 = test({\r\n  foo: true,\r\n  bar: () =\u003e {\r\n    // This is fine.\r\n  }\r\n})\r\n```\r\n\r\n**Expected behavior:** The first two `test` calls should infer the given object type correctly.\r\n\r\n**Actual behavior:** They instead infer the object type as `Test\u003cnever\u003e`. 😢\r\n\r\n**Playground Link:** [Click here][1]\r\n\r\n**Related Issues:** #17867 (sort of)\r\n\r\n- https://stackoverflow.com/questions/50198477/how-to-type-check-this-object-without-using-or-any\r\n\r\n[1]: http://www.typescriptlang.org/play/#src=type%20Test%3CK%20extends%20keyof%20any%3E%20%3D%20%7B%0D%0A%20%20%5BP%20in%20K%20%7C%20%22foo%22%5D%3A%20P%20extends%20%22foo%22%20%3F%20true%20%3A%20()%20%3D%3E%20any%0D%0A%7D%0D%0A%0D%0Afunction%20test%3CT%20extends%20Test%3Ckeyof%20T%3E%3E(arg%3A%20T)%20%7B%0D%0A%20%20%20%20return%20arg%3B%0D%0A%7D%0D%0A%0D%0Aconst%20res1%20%3D%20test(%7B%0D%0A%20%20foo%3A%20true%2C%0D%0A%20%20bar()%20%7B%0D%0A%20%20%20%20%2F%2F%20Notice%20the%20type%20param%20of%20%60test%60%20is%20inferred%20as%20%60Test%3Cnever%3E%60%0D%0A%20%20%7D%0D%0A%7D)%0D%0A%0D%0Aconst%20res2%20%3D%20test(%7B%0D%0A%20%20foo%3A%20true%2C%0D%0A%20%20bar%3A%20function%20()%20%7B%0D%0A%20%20%20%20%2F%2F%20Same%20error%20here.%0D%0A%20%20%7D%0D%0A%7D)%0D%0A%0D%0Aconst%20res3%20%3D%20test(%7B%0D%0A%20%20foo%3A%20true%2C%0D%0A%20%20bar%3A%20()%20%3D%3E%20%7B%0D%0A%20%20%20%20%2F%2F%20This%20is%20fine.%0D%0A%20%20%7D%0D%0A%7D)%0D%0A%0D%0Aconst%20res4%20%3D%20test(%7B%0D%0A%20%20foo%3A%20true%2C%0D%0A%20%20bar%2C%0D%0A%7D)%0D%0Afunction%20bar()%20%7B%0D%0A%20%20%2F%2F%20This%20is%20fine.%0D%0A%7D%0D%0A","author":{"url":"https://github.com/aleclarson","@type":"Person","name":"aleclarson"},"datePublished":"2019-01-21T23:07:28.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/29520/TypeScript/issues/29520"}