ModuleInfo.unitTest cannot be called twice

[Jacob Carlborg]

It seems it's not possible to call ModuleInfo.unitTest more than once.
The following code will not run the unit tests:

foreach (m ; ModuleInfo)
    if (m && m.unitTest)
        m.unitTest();

But this code will:

foreach (m ; ModuleInfo)
    if (m)
        if (auto fp = m.unitTest)
            fp();

Not that I'm storing the result of "m.unitTest" in a variable in the 
second example.

Am I doing something wrong here or is this a bug?

--
/Jacob Carlborg