Dupping in a nothrow function?

[bearophile]

It's now OK to create a new array in a nothrow function, but it seems dup is 
not allowed:


nothrow void foo(int[] a) {
    a.dup;
}
void main() {}


Errors with dmd 2.052, is this correct?
test.d(2): Error: _adDupT is not nothrow
test.d(1): Error: function test.foo 'foo' is nothrow yet may throw

Bye,
bearophile