René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Spreads instantiated with array subtypes types exhibit bad behavior","articleBody":"Found by playing around with @mattmccutchen's example at https://github.com/Microsoft/TypeScript/issues/26013#issuecomment-409330936:\r\n\r\n```ts\r\ninterface CoolArray\u003cE\u003e extends Array\u003cE\u003e { \r\n    hello: number;\r\n}\r\n\r\ndeclare function foo\u003cT extends any[]\u003e(cb: (...args: T) =\u003e void): void;\r\n\r\nfoo\u003cCoolArray\u003cany\u003e\u003e();    // error\r\nfoo\u003cCoolArray\u003cany\u003e\u003e(100); // error\r\nfoo\u003cCoolArray\u003cany\u003e\u003e(foo); // no error!!\r\n```\r\n\r\n**Expected**: All of these calls produce an error and have a good error message.\r\n**Actual**: The first two have bad errors, the last one is considered okay.","author":{"url":"https://github.com/DanielRosenwasser","@type":"Person","name":"DanielRosenwasser"},"datePublished":"2018-08-01T03:39:33.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":16},"url":"https://github.com/26110/TypeScript/issues/26110"}