<!-- 🚨 STOP 🚨 STOP 🚨 STOP 🚨 Half 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! Please help us by doing the following steps before logging an issue: * Search: https://github.com/Microsoft/TypeScript/search?type=Issues * Read the FAQ: https://github.com/Microsoft/TypeScript/wiki/FAQ Please fill in the *entire* template below. --> <!-- Please try to reproduce the issue with the latest published version. It may have already been fixed. For npm: `typescript@next` This is also the 'Nightly' version in the playground: http://www.typescriptlang.org/play/?ts=Nightly --> **TypeScript Version:** 4.2.0-dev.20201201 <!-- Search terms you tried before logging this (so others can find this issue more easily) --> **Search Terms:** Conditional types generics **Code** ```ts interface Foo<T, U extends T extends number? any: any> {} function foo<T>(bar: Foo<T, number>) {} ``` **Expected behavior:** No error, `U` is `any` **Actual behavior:** Error 2344: `Type 'number' does not satisfy the constraint 'T extends number? any: any'` **Playground Link:** <!-- A link to a TypeScript Playground "Share" link which demonstrates this behavior --> https://www.typescriptlang.org/play?ts=4.2.0-dev.20201201#code/JYOwLgpgTgZghgYwgAgGIHt0B4AqAaZAVWQgA9IQATAZ2RxPIitpAFcBbAI2gH5k4QATwBc-IQD5kAbwC+AWABQMViARhg6EMhiZc4gBSc4UURmz5kbLtHEBKaTKA **Related Issues:** <!-- Did you find other bugs that looked similar? --> Maybe #41040 ?