As explained in DAP006, Dapper.AOT can make use of the names in tuple syntax (for example (id: 42, name: "abc")). That’s the theory. In practice, we haven’t implemented that just yet, so … it isn’t going to work. Hey, we’re human.

Maybe just use an anonymous type instead?

Not yet supported:

var data = conn.Query<MyData>("somesql", (id: 42, name: "abc"));

Good:

var data = conn.Query<MyData>("somesql", new { id = 42, name = "abc" });