Can generics have default types?

Question presented to candidate: "Can a generic type parameter have a default? How does that interact with inference and with constraints, and where have you seen defaults used?"

What a strong answer should cover:

• Yes: interface Box<T = string> — writing Box alone means Box<string>; defaults arrived in TypeScript 2.3
• Rules: a parameter with a default is optional, required parameters cannot follow optional ones (TS2706), a default must satisfy its constraint (TS2344), and a default may refer to earlier parameters (<T, C = T[]>)
• For function calls, inference wins: the default only applies when there is nothing to infer from (box() vs box(10)); with neither, T becomes unknown
• No partial inference: pass one type argument explicitly and the rest come from their defaults, not from the arguments
• Good defaults: unknown for parse/fetch helpers, a loose event map for an emitter, React typings such as useState<S = undefined>()

Code / implementation expected: Optional — a generic interface or function with a default, and one call where inference overrides it.