[Help Needed] - Custom runtime assertion bug

[Hipreme]

So, I've been implementing the mini druntime using adam's initial 
work. Right now I've found a problem where I didn't seem to find 
anything about.

So, I've got this working: `assert(false, "Hello from assert");` 
which is `_d_assert_msg`.

The problem right now is the combination of `_d_assert_msg` and 
`_d_arraycatnTX`.

Both are implemented right now, but it fails on my test on:
```d
string t = "test";
assert(false, t~t);
```

The type info that I'm getting in the step of `_d_arraycatnTX` is 
null for some reason when ussing assertions. Does anyone knows 
why is this happening?

Needles to say, `_d_arraycatnTX` is already tested for situations 
where no assert is involved.