Using generic argument that extends something, stops inferring super keys when Exclude is used in addition to keyof and Pick

<!-- Please try to reproduce the issue with `typescript@next`. It may have already been fixed. --> **TypeScript Version:** 3.1.0 <!-- Search terms you tried before logging this (so others can find this issue more easily) --> **Search Terms:** keyof extends pick exclude **Code** ```ts interface Base { base1: number; base2: number; } class Data<T extends Base> { alpha(k:keyof Pick<T, Exclude<keyof T, "base1">>) { } beta(k:keyof Pick<T, keyof T>) { } } function wrapped<T extends Base>() { let d = new Data<T>(); d.alpha("base2"); // Argument of type '"base2"' is not assignable to parameter of type 'Exclude<keyof T, "base1">'. d.beta("base2"); // works } ``` **Expected behavior:** Both alpha and beta should work. **Actual behavior:** Alpha does not work: ` Argument of type '"base2"' is not assignable to parameter of type 'Exclude<keyof T, "base1">'. **Playground Link:** <!-- A link to a TypeScript Playground "Share" link which demonstrates this behavior --> [Playground link](https://www.typescriptlang.org/play/#src=interface%20Base%20%7B%0D%0A%20%20%20%20base1%3A%20number%3B%0D%0A%20%20%20%20base2%3A%20number%3B%0D%0A%7D%0D%0A%0D%0Aclass%20Data%3CT%20extends%20Base%3E%20%7B%0D%0A%20%20%20alpha(k%3Akeyof%20Pick%3CT%2C%20Exclude%3Ckeyof%20T%2C%20%22base1%22%3E%3E)%20%7B%20%20%20%7D%0D%0A%20%20%20%20beta(k%3Akeyof%20Pick%3CT%2C%20keyof%20T%3E)%20%7B%20%20%20%7D%0D%0A%7D%0D%0A%0D%0Afunction%20wrapped%3CT%20extends%20Base%3E()%20%7B%0D%0A%20%20%20%20let%20d%20%3D%20new%20Data%3CT%3E()%3B%0D%0A%20%20%20%20d.alpha(%22base2%22)%3B%20%2F%2F%20Argument%20of%20type%20'%22base2%22'%20is%20not%20assignable%20to%20parameter%20of%20type%20'Exclude%3Ckeyof%20T%2C%20%22base1%22%3E'.%20%0D%0A%20%20%20%20d.beta(%22base2%22)%3B%20%20%2F%2F%20works%0D%0A%7D%0D%0A) **Related Issues:** <!-- Did you find other bugs that looked similar? -->