`ArrayIndexOutOfBoundsException` while remapping mods for transform cache

[unilock]

Describe the crash

My very large modpack crashes during mod remapping while Quilt Loader (v0.29.3-beta.1) is preparing its transformation cache. The thrown exception provides very little information:

java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 2
	at org.quiltmc.loader.impl.lib.tinyremapper.TinyRemapper.waitForAll(TinyRemapper.java:1229)
	at org.quiltmc.loader.impl.lib.tinyremapper.TinyRemapper.apply(TinyRemapper.java:967)
	at org.quiltmc.loader.impl.transformer.RuntimeModRemapper.remap0(RuntimeModRemapper.java:201)
	at org.quiltmc.loader.impl.transformer.RuntimeModRemapper.remap(RuntimeModRemapper.java:135)
	at org.quiltmc.loader.impl.transformer.TransformCache.<init>(TransformCache.java:158)
	at org.quiltmc.loader.impl.transformer.TransformCacheGenerator.generate(TransformCacheGenerator.java:45)
	at org.quiltmc.loader.impl.transformer.TransformCacheManager.writeTransformCache(TransformCacheManager.java:302)
	at org.quiltmc.loader.impl.transformer.TransformCacheManager.createTransformCache(TransformCacheManager.java:275)
	at org.quiltmc.loader.impl.transformer.TransformCacheManager.populateTransformBundle(TransformCacheManager.java:105)
	at org.quiltmc.loader.impl.QuiltLoaderImpl.setup(QuiltLoaderImpl.java:377)
	at org.quiltmc.loader.impl.QuiltLoaderImpl.load(QuiltLoaderImpl.java:306)
	at org.quiltmc.loader.impl.launch.knot.Knot.init(Knot.java:150)
	at org.quiltmc.loader.impl.launch.knot.Knot.launch(Knot.java:79)
	at org.quiltmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:28)
	at org.prismlauncher.launcher.impl.StandardLauncher.launch(StandardLauncher.java:105)
	at org.prismlauncher.EntryPoint.listen(EntryPoint.java:129)
	at org.prismlauncher.EntryPoint.main(EntryPoint.java:70)
Caused by: java.util.concurrent.ExecutionException: java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 2
	at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:124)
	at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:193)
	at org.quiltmc.loader.impl.lib.tinyremapper.TinyRemapper.waitForAll(TinyRemapper.java:1226)
	... 16 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 2
	at org.quiltmc.loader.impl.lib.tinyremapper.AsmClassRemapper$AsmMethodRemapper.processLocals(AsmClassRemapper.java:344)
	at org.quiltmc.loader.impl.lib.tinyremapper.AsmClassRemapper$AsmMethodRemapper.visitEnd(AsmClassRemapper.java:310)
	at org.objectweb.asm.ClassReader.readMethod(ClassReader.java:1516)
	at org.objectweb.asm.ClassReader.accept(ClassReader.java:745)
	at org.objectweb.asm.ClassReader.accept(ClassReader.java:425)
	at org.quiltmc.loader.impl.lib.tinyremapper.TinyRemapper.apply(TinyRemapper.java:1132)
	at org.quiltmc.loader.impl.lib.tinyremapper.TinyRemapper.lambda$apply$5(TinyRemapper.java:963)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:545)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614)
	at java.base/java.lang.Thread.run(Thread.java:1474)

I suspect some mod is doing something very strange to cause this issue, but I have no idea which mod it could be.

Which environment crashed?

Client

Logs

https://mclo.gs/vVL47Xl

[unilock]

Downgrading to Quilt Loader 0.28.1 works around the issue, but obviously isn't an ideal solution.