string <-> null/bool implicit conversion

[via Digitalmars-d]

On Thursday, 20 August 2015 at 18:04:00 UTC, Steven Schveighoffer 
wrote:
> On 8/20/15 1:50 PM, Steven Schveighoffer wrote:
>
>> The "truthiness" of an array says it's true ONLY if both the 
>> pointer and
>> length are 0.
>
> Ugh, *false* only if they are both 0. If either are not zero, 
> then it's true.
>
> -Steve

In other words, it's true when the pointer is not null. i.e. in 
the context of boolean evaluation, it has the semantics of 
string.ptr

It's just making the concept of an empty array a grey cloud.

Consider this:

string a = "";
string b;
	
writeln(a ? "a" : "null");
writeln(b ? "b" : "null");
writeln(a.idup ? "adup" : "null");
writeln(b.idup ? "bdup" : "null");

Output:
a
null
null
null


What?