web::uri::port() says "Returns -1 if no port is specified."

This is the initial value of a default-constructed web::uri or web::uri_builder.

However, web::uri::is_port_default() tests for port() == 0.

Parsing a URI string e.g. using the web::uri constructor, results in the port being set to 0 if the URI string doesn't specify a port.

This means that:
web::uri(U("http://example.com/")) != web::uri_builder().set_scheme(U("http")).set_host(U("example.com")).to_uri()

That was surprising to me.

Are 'port unspecified' (-1) and 'port default' really supposed to be distinct?
In other words, should a user of web::uri_builder have to explicitly set default port?

web::uri(U("http://example.com/")) == web::uri_builder().set_scheme(U("http")).set_host(U("example.com")).set_port(0).to_uri()

If so, since the fact that 0 indicates default is not documented, would it be worth adding uri_builder::set_default_port()?