Question about function type parameter type hints?

[Dicebot]

On Monday, 15 July 2013 at 18:56:38 UTC, Gary Willoughby wrote:
> Are the two above class declarations achieving the same thing? 
> i.e. is the type hint of the second snippet shorthand for the 
> first's 'if'? If so which is preferred?

No, ":" stands for "same or implicitly convertible" while "==" is 
strict "same":

T foo1(T : int)()
{
	return T.init;
}

T foo2(T)()
	if (is(T == int))
{
	return T.init;
}

void main()
{
	foo1!short();
	foo2!short(); // error
}

As far as I know there are no "==" syntax for template 
specialization. Usually template specialization syntax is 
preferable for simple cases because it is more readable but any 
complex case pretty much requires "if" constraint.