While  porting kioslave/trash  I encountered 

two errors , one is /kioslave/trash/kinterprocesslock.h:110:15: error: forward declaration of ‘struct KInterProcessLock::Private’

 I tried adding class Private; above the class KInterProcessLock {} among many other things but that is not working here .The same code has no such syntax problem in plasma 1 .

And second error is kinterprocesslock.cpp:78:22: error: invalid use of incomplete type ‘struct KInterProcessLock::Private’

Please suggest something 

Regards