René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Fails to calculate arguments length, when combining tuple spread with extra arguments","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:**  3.3.0-dev.20190103\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:** tuple, array, spread, arguments, length\r\n\r\n**Code**\r\n\r\n```ts\r\nconst three: [number, number, number] = [1, 2, 3];\r\nconst two: [number, number] = [1, 2];\r\nconst one: [number] = [1]; \r\n\r\nconst foo = (a: number, b: number, c: number) =\u003e undefined;\r\n\r\n// EXPECTED: correctly realizes there are three args\r\nfoo(...three);\r\n\r\n// EXPECTED: correctly realizes there are two args\r\n// error: Expected 3 arguments, but got 2.\r\nfoo(...two);\r\n\r\n// EXPECTED: correctly realizes there is one arg\r\n// error: Expected 3 arguments, but got 1.\r\nfoo(...one);\r\n\r\n// UNEXPECTED: does not realize there are three args\r\n// error: Expected 3 arguments, but got 1 or more.\r\nfoo(...two, 2);\r\n\r\n// UNEXPECTED: does not realize there are three args\r\n// error: Expected 3 arguments, but got 1 or more.\r\nfoo(...one, 2, 3);\r\n```\r\n\r\n**Expected behavior:**\r\nCorrectly calculate the count of the arguments passed into `foo`. Add the additional arguments to the length of the tuple. Basically the last two examples should not throw an error.\r\n\r\n**Actual behavior:**\r\nWhen adding additional arguments after the spreaded tuple, TS fails to calculate the total amount of arguments end expects the amount of the additional arguments \"+ more\".\r\n\r\n**Playground Link:** [Link](http://www.typescriptlang.org/play/#src=const%20three%3A%20%5Bnumber%2C%20number%2C%20number%5D%20%3D%20%5B1%2C%202%2C%203%5D%3B%0D%0Aconst%20two%3A%20%5Bnumber%2C%20number%5D%20%3D%20%5B1%2C%202%5D%3B%0D%0Aconst%20one%3A%20%5Bnumber%5D%20%3D%20%5B1%5D%3B%20%0D%0A%0D%0Aconst%20foo%20%3D%20(a%3A%20number%2C%20b%3A%20number%2C%20c%3A%20number)%20%3D%3E%20undefined%3B%0D%0A%0D%0A%2F%2F%20EXPECTED%3A%20correctly%20realizes%20there%20are%20three%20args%0D%0Afoo(...three)%3B%0D%0A%0D%0A%2F%2F%20EXPECTED%3A%20correctly%20realizes%20there%20are%20two%20args%0D%0Afoo(...two)%3B%0D%0A%0D%0A%2F%2F%20EXPECTED%3A%20correctly%20realizes%20there%20is%20one%20arg%0D%0Afoo(...one)%3B%0D%0A%0D%0A%2F%2F%20UNEXPECTED%3A%20does%20not%20realize%20there%20are%20three%20args%0D%0Afoo(...two%2C%203)%3B%0D%0A%0D%0A%2F%2F%20UNEXPECTED%3A%20does%20not%20realize%20there%20are%20three%20args%0D%0Afoo(...one%2C%202%2C%203)%3B%0D%0A)\r\n\r\n**Related Issues:** \u003c!-- Did you find other bugs that looked similar? --\u003e\r\n","author":{"url":"https://github.com/hpohlmeyer","@type":"Person","name":"hpohlmeyer"},"datePublished":"2019-01-03T15:21:39.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/29248/TypeScript/issues/29248"}