René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Improve error message for using value as type","articleBody":"**TypeScript Version:**  3.4.0-dev.20190206\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:** \"cannot find name\" type error\r\n\r\n**Code**\r\n\r\nIf you use a type as a value you get a nice error message:\r\n\r\n```ts\r\ntype t = number;\r\nlet x = t;\r\n// error TS2693: 't' only refers to a type, but is being used as a value here.\r\n```\r\n\r\nBut if you do the same thing in reverse, you get a really confusing one:\r\n\r\n```ts\r\nlet t = 3;\r\nlet x: t;\r\n// error TS2304: Cannot find name 't'.\r\n```\r\n\r\n**Expected behavior:**\r\n\r\nError message should say something more like the type one.\r\n\r\n**Actual behavior:**\r\n\r\nError message suggests there is no 't' in scope at all, which is very confusing especially when you have imported t from some other file and you thought it was a type.\r\n\r\n**Playground Link:** \r\n\r\nhttps://www.typescriptlang.org/play/#src=%0D%0Afunction%20goodError()%20%7B%0D%0A%20%20%20%20type%20t%20%3D%20number%3B%0D%0A%20%20%20%20let%20x%20%3D%20t%3B%20%2F%2F%20good%20error%20message%0D%0A%7D%0D%0A%0D%0Afunction%20badError()%20%7B%0D%0A%20%20%20%20let%20t%20%3D%203%3B%0D%0A%20%20%20%20let%20x%3A%20t%3B%20%2F%2F%20bad%20error%20message%0D%0A%7D\r\n\r\n**Related Issues:**\r\n\r\nThere are some around this same problem with namespaces I think, like \r\nhttps://github.com/Microsoft/TypeScript/issues/26391 or https://github.com/Microsoft/TypeScript/issues/12075\r\n\r\nI think this issue is more broadly complaining about issues in this area:\r\nhttps://github.com/Microsoft/TypeScript/issues/27630\r\nBut the issue I'm filing here is very specific and concrete, with an easy repro.\r\n\r\nThis issue discusses some suggested fixes for this issue, but I think first we need to fix the error message.\r\nhttps://github.com/Microsoft/TypeScript/issues/28975\r\n","author":{"url":"https://github.com/evmar","@type":"Person","name":"evmar"},"datePublished":"2019-02-06T17:29:33.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/29778/TypeScript/issues/29778"}