Purity of std.conv.to!string

[Jack Stouffer via Digitalmars-d-learn]

On Saturday, 26 September 2015 at 17:08:00 UTC, Nordlöw wrote:
> Why is the following code not pure:
>
>     float x = 3.14;
>     import std.conv : to;
>     auto y = x.to!string;
>
>
> ???
>
> Is there a reason for it not being pure? If not, this is a 
> serious problem as this is such a fundamental function.

Please make an issue on https://issues.dlang.org and I'll take a 
look a this later. Most of the functions in std.conv are 
templated so it must be some internal function that's not 
properly annotated, or it's using manual memory management.