Fix incorrect check.

include/common.h

@@ -59,7 +59,7 @@ class OBType
  OBType() = delete;
  OBType(OBType&&) = delete;
  OBType(OBType&) = delete;
- OBType(const ObjectBase* arg):iszero(0==p) {if(0==arg) p=0; else if(typeid(*arg)==typeid(O)) p=dynamic_cast<const O*>(arg); else p=0;}
+ OBType(const ObjectBase* arg):iszero(0==arg) {if(0==arg) p=0; else if(typeid(*arg)==typeid(O)) p=dynamic_cast<const O*>(arg); else p=0;}
  const O* operator->() const {return p;}
  operator bool() const {return 0!=p;}
  operator const O*() const {return p;}