std.range this._input.opIndex(index) error

[Tyro[a.c.edwards]]

Attempting to compile the following from snippet

	auto r = iota(0, 10, 1);
	assert(equal(r, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9][]));

from the documentation, I encountered following error

range.d(1184): Error: this._input.opIndex(index) is not an lvalue

Looking at the code I find "return _input[index];" on line 1184. The 
variable _input is defined as R _input in the template Take(R) which is 
the template instantiated to create iota. Problem is, it is obvious why 
this doesn't work since the Range data variable "_input" is accessed the 
same way on multiple occasions throughout the file, a Range variable can 
obviously supports random access, and no attempt is being made to modify 
the range at this point in the code. Any information would be greatly 
appreciated?

Thanks in advance,
Andrew