Steps to reproduce:

1. Obtain 3 enchanted books: 1 with Sharpness, 1 with Density and 1 with Breach
2. Attempt to combine the books with Sharpness and Density using an anvil
3. Attempt to combine the books with Sharpness and Breach using an anvil

Observed result:
You can't combine Sharpness with Density or Breach, despite the fact that you cannot enchant any weapon that supports Sharpness with Breach and Density and vice versa.

Expected result:
You can combine Sharpness with Density or Breach.

Original description:
I was using the /enchant command to put tons of enchants on a book, but because I put Density on it would not let me put sharpness, which makes no sense because sharpness cant be put on a mace and density cant be put on a sword.