Usually an icicle can be found at the point of the leak. If there is a block of ice but there are no cubes, the defrost cycle may be running too long, melting the ice and other items in the freezer. This happens when the defrost limit switch fails in a closed position, which is not common. After the defrost cycle, things refreeze. A look at the ice cream in the freezer can offer an indicator of trouble with the defrost cycle.
Ice cream is about half air.
When it melts, the air rises out, and when it refreezes, a full container may compress to one that is only half full of very dense ice cream. If you buy ice cream just to test your freezer, you know you are going to eat it. After 2 or more hours, put an ice cube in the glass. If the cube has melted by the next day, you need a new defrost limit switch. The usual ice maker problem is that it doesn't make ice.