Function map_key_supported 

pub fn map_key_supported(ast: &Ast, key: Id<TypeNode>) -> bool

Whether the key type of a map is one a java.util.Map can be keyed by: a primitive, a string, an enumeration or a bitmask, whose Java objects compare by value, and a structure, a union or a bit set, whose generated class has equals and hashCode over its members (see equals_and_hash_code).