On Saturday, 12 March 2016 at 09:56:48 UTC, Uldis wrote:
dump(a); // line 10
a.length = 0;
dump(a);
a ~= [1,2,3];
dump(a);
a.length = 0;
dump(a);
a ~= [4,5,6];
dump(a);
I'll let others more knowledgeable explain why, but tack an a.assumeSafeAppend() after the length change and you'll get your desired behaviour.
