QueryAsync with multiple types does not work

[ricochetbrown]

`var results = await connection.QueryAsync(
"[dbo].[GetSomething]",
types: new[]
{
typeof(Something),
typeof(ASubThing),
typeof(AnotherSubThing)
},
map: objects =>
{
var result = objects[0] as Something?? new Something();

                result.FirstSubThing= objects[1] as ASubThing?? new ASubThing();
                result.SecondSubThing= objects[2] as AnotherSubThing?? new AnotherSubThing();

                return result;
            },
            dbArgs,
            commandType: CommandType.StoredProcedure);`

moq.dapper continues to give an error saying that (When using the multi-mapping APIs ensure you set the splitOn param if you have keys other than Id (Parameter 'splitOn') even though the code works fine when the api is running.