Moss requires air above a replaceable block to spread

The bug

When using bone meal on moss blocks, they are supposed to turn the adjacent blocks into moss blocks, however if the block has a torch, chain block, iron bar, fence, or any other block on top of them, the moss does not spread.

How to reproduce

1. Place a moss block with stone next to it, with a torch on top of the stone
2. Apply bone meal to the moss block
   The moss does not spread to the stone

Expected behavior

The moss would spread to the stone regardless of whether or not a block is present above the stone.