On 11/16/2016 03:58 PM, Jorge Timón via bitcoin-dev wrote:
> On Wed, Nov 16, 2016 at 3:18 PM, Thomas Kerin via bitcoin-dev
> <bitcoin-dev@lists.linuxfoundation.org> wrote:
>> BIP30 actually was given similar treatment after a reasonable amount of time
>> had passed.
>> https://github.com/bitcoin/bitcoin/blob/master/src/main.cpp#L2392
> 
> This is not really the same. BIP30 is not validated after BIP34 is
> active because blocks complying with BIP34 will always necessarily
> comply with BIP30 (ie coinbases cannot be duplicated after they
> include the block height).

This is a misinterpretation of BIP30. Duplicate transaction hashes can
and will happen and are perfectly valid in Bitcoin. BIP34 does not
prevent this.

e