if (!invFrameAtNullCheck.isValid()) {  return false; }
	private boolean isDerefOfNonNullValue(Location locationOfDeref, IsNullValueFrame invFrameAtNullCheck)			throws DataflowAnalysisException {		int instance = invFrameAtNullCheck.getInstanceSlot(				locationOfDeref.getHandle().getInstruction(),				methodGen.getConstantPool());		return isNonNullValue(invFrameAtNullCheck, instance);	}