Hi,
I'm trying to write a function that saves some structs as csv
file:
```
string toCsv(const(StatStorage) storage) {
return storage.values
.map!(a => [ a.name, a.begin.toISOExtString,
a.end.toISOExtString, a.status.to!string ])
.map!(a => a.join(','))
.join('\n');
}
```
I think that it's obvious that this function has no external
state and from my understanding, it should be a pure function.
But when I declare it as `pure` I get an error `Error: pure
function 'trial.reporters.stats.toCsv' cannot call impure
function 'std.array.join!(MapResult!(__lambda3,
MapResult!(__lambda2, const(Stat)[])), char).join'`.
What am I missing here?
