Dapper.Contrib Insert<T>(Enumerable<T> list) -> list<T> with key valued

I was looking through the code SqlMapperExtensions.cs in dapper.contrib

At line 386 I can find this:

var cmd = $"insert into {name} ({sbColumnList}) values ({sbParameterList})";
returnVal = connection.Execute(cmd, entityToInsert, transaction, commandTimeout);

I was looking for a way to get as output the same list in input but with Id (the field with [Key] parameter) valued.

I was thinking about something like this:

var cmd = $"insert into {name} ({sbColumnList}) OUTPUT {sbInsertedColumnList} , Insert.WhenCreated into @Inserted values ({sbParameterList}); SELECT * FROM @Inserted";
returnVal = connection.Query<T>(cmd, entityToInsert, transaction, commandTimeout);

where {sbInsertedColumnList} is the same as {sbColumnList} but with Inserted. as prefix for any column.

Could this be a good idea?

Start with SqlMapperExtensions.cs around line 386 and trace the Dapper.Contrib Insert(IEnumerable) path, including how the [Key] field is handled. Clarify the expected returned list and database-specific behavior with maintainers; done means an agreed implementation that returns inserted entities with their key values.