**TypeScript Version:** 3.1.0-dev.20180802 **Search Terms:** Mapped tuple type generic infer array **Code** ```ts type Element<T> = T extends Array<infer U> ? U : never; type Mapped<T> = { [K in keyof T]: T[K] }; type F<T> = Element<Mapped<T>>; type R1 = F<[string, number, boolean]>; // never type R2 = Element<Mapped<[string, number, boolean]>>; // string | number | boolean ``` **Expected behavior:** The type of `R1` should be `string | number | boolean`. **Actual behavior:** The type of `R1` is `never`.