Why is mangling different for separate compilation?

[Chris Wright via Digitalmars-d]

On Sun, 28 Feb 2016 20:23:59 +0100, Jacob Carlborg wrote:

> On 2016-02-27 04:51, Walter Bright wrote:
> 
>> It uses a sequence number to generate different ids for the unit tests.
>> In the former, it's the 531st unit test, the latter, the first.
> 
> It sounds like the compiler is seeing different unit tests during the
> different compilation. But why is that the case.

Or like there's a global counter that is incremented for each unittest. A 
different order of traversal of unittests would result in a different 
mangled name for the same unittest in different runs.