* Only include statements whose side-effects are relevant (i.e. contribute to exports or affect global state) ([#253](https://github.com/rollup/rollup/pull/253)) ([#253](https://github.com/rollup/rollup/pull/253))
* Exclude dead branches from analysis and inclusion ([#249](https://github.com/rollup/rollup/pull/249))
* Add `aggressive: true` option to eliminate all side-effects outside entry module
* More informative error when re-exporting non-existent binding ([#274](https://github.com/rollup/rollup/issues/274))