Prettier 2.7.1
Playground link

--parser babel-ts

Input:

type Foo<T> = T extends (...a: any[]) => (infer R extends string) ? R : never;

Output:

type Foo<T> = T extends (...a: any[]) => infer R extends string ? R : never;

Expected behavior:

The parentheses around (infer R extends string) should be preserved. Removing them results in an error with TypeScript, as shown in the TS Playground (link):