Why do I get stack overflow?

[Ary Borenszweig]

When I compile this code I get "stack overflow" printed in the console. 
Anyone know why?

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int fact(int X)() {
	if(X == 0) {
		return 1;
	} else {
		int temp = fact!(X - 1)();
		return X * temp;
	}
}

const someVar = fact!(0)();
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