map and Set does not support arbitrary keys

[prashanth-hegde]

map currently only supports basic types (int, string, ...) as keys. A custom struct is not supported as keys. Example:

struct PersonalInfo {
  name string
  age int
}

mut info_map := map[PersonalInfo]int{}

gives this error

cgen error: map key type not supported

Set<T> also uses map behind the scenes and is indirectly affected.

[depperm]

see discussion https://github.com/vlang/v/discussions/11927