Example:

  Array!int a;

Error:

std/container.d(1660): Error: function core.stdc.stdlib.free (void* ptr) is not callable using argument types (int[])
std/container.d(1660): Error: cannot implicitly convert expression ((*this._data)._payload) of type int[] to void*

The fix is trivial, just add .ptr in line 1660:

-            free(_data._payload);
+            free(_data._payload.ptr);

But why aren't the unittests picking this up?  I've investigated a bit, and found that when Array!int is declared in the std.concurrency unittests, the int[] is implicitly cast to void* in the call to free().  However, this doesn't happen when Array!int is declared in user code.  Very strange.