The standard library Hash_Key api defines the argument type for the typelocked_hashtable_g defined in src/lib/src/typelocked-hashtable-g.pkg.
The Hash_Key api is implemented by the bool package.
The Hash_Key api source code is in src/lib/src/hash-key.api.
See also: Hashtable api.
The above information is manually maintained and may contain errors.
api { Hash_Key; hash_value : Hash_Key -> Unt; same_key : (Hash_Key , Hash_Key) -> Bool;};