Version: 1.15.2,
Minecraft crashes instantly on launch when Optifabric and Litematica are installed.
(It doesn't crash if only one of them is installed)
Minecraft doesn't crash if mods other than Litematica from maruohon are installed.

Mods:
fabric-api-0.4.32+build.292-1.15
litematica-fabric-1.15.2-0.0.0-dev.20200212.174750
malilib-fabric-1.15.2-0.10.0-dev.20+arne.2
optifabric-1.0.0-beta1
preview_OptiFine_1.15.2_HD_U_G1_pre1

Crash Log:
org.spongepowered.asm.mixin.transformer.throwables.MixinTransformerError: An unexpected critical error was encountered

.txt File