It ends up making two similar types, [N]uint8 of both
alg and noalg varieties. Comparsions between the two then
don't come out equal when they should.
In particular, the type *[N]uint8 has an Elem pointer which
must point to one of the above two types; it can't point to both.
Thus allocating a *[N]uint8 and dereferencing it might be a
different type than a [N]uint8.
The fix is easy. Making a small test for this is really hard. It
requires that both a argless defer and the test be imported by a
common parent package. This is why a main binary doesn't see this
issue, but a test does (as Agniva noticed), because there's a wrapper
package that imports both the test and the defer.
Types like [N]uint8 don't really need to be marked noalg anyway,
as the generated code (if any) will be shared among all
vanilla memory types of the same size.