I crashed when using "minecraft:log2:2" in place of "minecraft:grass" in the superflat generation. it is an invalid block but it shouldn't cause a crash.

---- Minecraft Crash Report ----
// Don't do that.

Time: 12/04/15 8:36 PM
Description: Updating screen events

java.lang.IllegalArgumentException: Cannot set property amn

to oak on block minecraft:log2, it is not an allowed value
at amb$a.a(SourceFile:124)
at aih.a(SourceFile:54)
at aqb.<init>(SourceFile:25)
at aqa.a(SourceFile:161)
at aqa.a(SourceFile:176)
at aqa.a(SourceFile:199)
at axb.a(SourceFile:59)
at axr.a(SourceFile:192)
at axv.a(SourceFile:350)
at axr.a(SourceFile:179)
at axv.k(SourceFile:413)
at axr.k(SourceFile:167)
at axv.p(SourceFile:390)
at avf.s(SourceFile:1497)
at avf.av(SourceFile:888)
at avf.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Stacktrace:
at amb$a.a(SourceFile:124)
at aih.a(SourceFile:54)
at aqb.<init>(SourceFile:25)
at aqa.a(SourceFile:161)
at aqa.a(SourceFile:176)
at aqa.a(SourceFile:199)
at axb.a(SourceFile:59)
at axr.a(SourceFile:192)
at axv.a(SourceFile:350)
at axr.a(SourceFile:179)
at axv.k(SourceFile:413)
at axr.k(SourceFile:167)
at axv.p(SourceFile:390)

– Affected screen –
Details:
Screen name: axr
Stacktrace:
at avf.s(SourceFile:1497)
at avf.av(SourceFile:888)
at avf.a(SourceFile:325)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.8.3
Operating System: Windows 8.1 (amd64) version 6.3
CPU: 2x AMD E1-2500 APU with Radeon(TM) HD Graphics
Java Version: 1.7.0_76, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 125017768 bytes (119 MB) / 276865024 bytes (264 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.8.3
LWJGL: 2.9.4
OpenGL: AMD Radeon HD 8240 GL version 4.3.12682 Compatibility Profile Context 13.301.1001.1001, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: [Custom Panorama M8]
Current Language: Canadian English (Canada)
Profiler Position: N/A (disabled)