When trying to place a torch under a block, not on the wall, but directly under a block - like the image shows attached to this post - the game crashes.
Probably not as intended by the Mojang team.
Environment
Windows 7 64-bit, Minecraft 17w15a vanilla/snapshot, Java 1.8.0_25 64bit.
CPU 12x Intel(R) Core(TM1) i7-5820K CPU @ 3.30GHz, Mem: 8089MB, Display 1920x1080 GeForce GTX 970 / 4.5.0 NVIDIA 376.33
Duplicate of MC-115807, please search before creating a report.