Upon placing a redstone lamp below bedrock, a client will crash reliably with an arrayIndexOutOfBounds.

Stacktrace:
java.lang.ArrayIndexOutOfBoundsException: -1
at net.minecraft.world.chunk.Chunk.func_76610_a(Chunk.java:640)
at net.minecraft.world.chunk.Chunk.func_76597_e(Chunk.java:981)
at net.minecraft.world.ChunkCache.func_72796_p(ChunkCache.java:115)
at mrtjp.projectred.core.BasicUtils.getTileEntity(BasicUtils.java:92)
at mrtjp.projectred.illumination.BlockLamp.getLightValue(BlockLamp.java:85)
at net.minecraft.block.Block.func_71874_e(Block.java:519)
at net.minecraft.client.renderer.RenderBlocks.func_78578_a(RenderBlocks.java:4271)
at net.minecraft.client.renderer.RenderBlocks.func_78570_q(RenderBlocks.java:4174)
at mrtjp.projectred.illumination.LampISBRH.renderWorldBlock(LampISBRH.java:44)
at cpw.mods.fml.client.registry.RenderingRegistry.renderWorldBlock(RenderingRegistry.java:152)
at FMLRenderAccessLibrary.renderWorldBlock(FMLRenderAccessLibrary.java:57)
at net.minecraft.client.renderer.RenderBlocks.func_78612_b(RenderBlocks.java:485)
at net.minecraft.client.renderer.WorldRenderer.func_78907_a(WorldRenderer.java:224)
at net.minecraft.client.renderer.RenderGlobal.func_72716_a(RenderGlobal.java:1551)
at net.minecraft.client.renderer.EntityRenderer.func_78471_a(EntityRenderer.java:1129)
at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:1006)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:946)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:838)
at net.minecraft.client.main.Main.main(SourceFile:101)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)
at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

Not that you SHOULD be placing things below/at bedrock, but fixed via 3304e83