https://go.dev/ref/spec#Map_types https://go.dev/ref/spec#Map_types says that is allowed. > If the key type is an interface type, these comparison operators mu

https://go.dev/ref/spec#Map_types https://go.dev/ref/spec#Map_types says that is allowed. > If the key type is an interface type, these comparison operators must be defined for the dynamic key values; failure will cause a run-time panic.