When you put a stair in front of a redstone torch, this is black and when aren't ligth this shines

Put the summary of the bug you're having here

What I expected to happen was...:
I want hide a redstone torch

What actually happened was...:
The stair shines

Steps to Reproduce:
1. Put a redstone torch
2. Put a stair in front of the redstone torch
3. Look (must be dark)