The manual says about array's concatenation :

>Concatenation always creates a copy of its operands, even if one of the operands is a 0 length array, so:
>	a = b			a refers to b
>	a = b ~ c[0..0]		a refers to a copy of b

I think it is a very good policy.

whereas in the following program ,
I assume it should be 2. is it a bug?

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int[] a,b,c;
a = new int[3];
b = new int[3];
a[1] = 2;
c = a ~ b[0..0];
a[1] = 4;
printf("%d",c[1]); // result : output 4.
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yaneurao.