Reconcealed object bug

From IFWiki

The reconcealed object bug is a programming error that can occur in games written in Inform when an object is coded with the concealed attribute, and then later fails to clear the attribute when the object should no longer be concealed.

For example, suppose that an NPC named Patricia is wearing a copper bracelet, and that the bracelet is coded with the concealed attribute to prevent it from being listed separately in the room description. And also suppose that the PC does some favor for Patricia so she gives the bracelet to the PC as a reward.

The bug occurs when the PC drops the bracelet and the bracelet is once again concealed from view. The bug is easily fixed by clearing the concealed attribute from the bracelet when Patricia gives it to the PC.