If the player is inside of a block, that block is no longer rendered

The bug

When inside of a block (so that you would suffocate in it in survival mode), the block the player is inside of no longer renders. This allows players to see through the world.

This bug does not happen in spectator mode, or if the GUI is not visible.

To reproduce

1. Switch into Survival or Creative mode
2. Run /tp @s ~ ~-3 ~ while standing on the ground of a normal world
   → You're inside of the ground and can see through all the solid blocks