C++ guys hate static_if?

[Timon Gehr]

On 03/14/2013 06:51 PM, Andrei Alexandrescu wrote:
> On 3/14/13 1:48 PM, H. S. Teoh wrote:
>> I don't agree. Phobos is a prime example. Does Phobos have unittests?
>> Yes, and lots of them. Does it still have non-compilable template
>> instantiations? Yes, because unittests can't cover all possibilities --
>> there are too many possible combinations of template arguments. There
>> are bound to be untested combinations which don't work but we're unaware
>> of.
>
> If you found a few, that would be great. I don't think you'll have an
> easy time.
>
> Andrei
>

Challenge accepted. Clearly the Phobos developers do not instantiate 
their templates before shipping them. :o)

The following breaks most of std.range, and most of std.algorithm could 
likely be broken too, but I am too lazy to investigate.

import std.range, std.algorithm;

struct TrollFace{
	@property string front()const{ return "troll"; }
	@property string back()const{ return "face"; }
	@property bool empty()const{ return true; }
	void popFront()const{ }
	void popBack()const{ }
	@property inout(TrollFace) save()inout{ return this; }
	auto opIndex(size_t index){ return front; }
	@property size_t length()inout{ return 0; }
	int* x;
}
struct TrollierFace{
	TrollFace face;
	alias face this;
	@disable this(this);
	@property inout(TrollierFace) save()inout{ return 
inout(TrollierFace)(face); }
}

void main(){
	immutable TrollFace a,b,c;
	a.retro();
	a.stride(2);
	chain(a,b,c);
	roundRobin(a,b,c);
	a.radial();
	a.radial(0);
	a.take(2);
	(immutable(TrollierFace)()).takeExactly(2);
	(immutable(TrollierFace)()).takeOne();
	(immutable(TrollierFace)()).takeNone();
	(immutable(TrollierFace)()).drop(2);
	(immutable(TrollierFace)()).dropExactly(0);
	(immutable(TrollierFace)()).dropOne();
	(immutable(TrollierFace)()).repeat();
	a.cycle();
	a.zip(b);
	lockstep((immutable(TrollierFace)()),b);
	a.frontTransversal();
	a.transversal(0);
	a.indexed([0]);
	a.chunks(5);
	a.filter!(a=>true);
	a.map!(a=>a);
	// ... (and so on)
}