PVS-Studio warning V564 for KDE4

DataAccess::DataAccessFlags typeToDataAccessFlags(....)
{
  DataAccess::DataAccessFlags ret = DataAccess::Read;
  TypePtr< ReferenceType > reftype=type.cast<ReferenceType>();
  if(reftype && reftype->baseType() &&
     !reftype->baseType()->modifiers() &    //<==
     AbstractType::ConstModifier)
    ret |= DataAccess::Write;

  return ret;
}

This suspicious code was found in KDE4 project by PVS-Studio static code analyzer.
Warning message is:
V564 The '&' operator is applied to bool type value. You've probably forgotten to include parentheses or intended to use the '&&' operator. usedecoratorvisitor.cpp 40

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/