I'm getting a crash when I'm converting a double to an uint64_t.
```
std.conv.ConvException@/usr/local/opt/dmd/include/dlang/dmd/std/conv.d(2054):
Value (1596) does not match any member value of enum '__c_ulonglong'
```
I've narrowed down the code to this:
```
static import std.conv;
double thing = 42.0;
std.conv.to!(uint64_t)(thing);
```
which works just fine on https://run.dlang.io/ or in a
single-file dmd invocation. When I compile and run it locally on
my mac as part of a specific large app using dub, it always
crashes like this.
Where would I even start debugging this?
DMD64 D Compiler v2.093.0
DUB version 1.22.0, built on Jul 9 2020
