Associative array with duplicated keys?

[cym13 via Digitalmars-d-learn]

On Friday, 6 November 2015 at 14:28:53 UTC, cym13 wrote:
>     auto aa = ["a":10, "b", 42, "a":20];

This should read    auto aa = ["a":10, "b":42, "a":20];  of 
course.