module Xsg
  def self.bad_method(argument)
    return if argument
    dummy_assign = true
  end
end

d:\temp>jrubyc test.rb && jruby -e "require 'jruby'; JRuby.runtime.debug = true; require './test.class'"
java.lang.reflect.InvocationTargetException
        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 org.jruby.runtime.load.CompiledScriptLoader.loadScriptFromFile(CompiledScriptLoader.java:35)
        at org.jruby.runtime.load.LibrarySearcher$ClassResourceLibrary.load(LibrarySearcher.java:257)
        at org.jruby.runtime.load.LibrarySearcher$FoundLibrary.load(LibrarySearcher.java:35)
        at org.jruby.runtime.load.LoadService.tryLoadingLibraryOrScript(LoadService.java:896)
        at org.jruby.runtime.load.LoadService.smartLoadInternal(LoadService.java:541)
        at org.jruby.runtime.load.LoadService.requireCommon(LoadService.java:426)
        at org.jruby.runtime.load.LoadService.require(LoadService.java:392)
        at org.jruby.RubyKernel.requireCommon(RubyKernel.java:946)
        at org.jruby.RubyKernel.require19(RubyKernel.java:939)
        at org.jruby.RubyKernel$INVOKER$s$1$0$require19.call(RubyKernel$INVOKER$s$1$0$require19.gen)
        at org.jruby.internal.runtime.methods.JavaMethod$JavaMethodOneOrNBlock.call(JavaMethod.java:380)
        at org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:61)
        at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:161)
        at org.jruby.ir.interpreter.InterpreterEngine.processCall(InterpreterEngine.java:290)
        at org.jruby.ir.interpreter.StartupInterpreterEngine.interpret(StartupInterpreterEngine.java:77)
        at org.jruby.ir.interpreter.InterpreterEngine.interpret(InterpreterEngine.java:83)
        at org.jruby.internal.runtime.methods.MixedModeIRMethod.INTERPRET_METHOD(MixedModeIRMethod.java:197)
        at org.jruby.internal.runtime.methods.MixedModeIRMethod.call(MixedModeIRMethod.java:183)
        at org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:197)
        at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:313)
        at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:163)
        at DashE.invokeOther5:require(-e)
        at DashE.RUBY$script(-e:1)
        at java.lang.invoke.MethodHandle.invokeWithArguments(Unknown Source)
        at org.jruby.ir.Compiler$1.load(Compiler.java:111)
        at org.jruby.Ruby.runScript(Ruby.java:821)
        at org.jruby.Ruby.runScript(Ruby.java:813)
        at org.jruby.Ruby.runNormally(Ruby.java:751)
        at org.jruby.Ruby.runFromMain(Ruby.java:573)
        at org.jruby.Main.doRunFromMain(Main.java:409)
        at org.jruby.Main.internalRun(Main.java:304)
        at org.jruby.Main.run(Main.java:233)
        at org.jruby.Main.main(Main.java:200)
Caused by: java.lang.IllegalArgumentException: Unhandled operation: unbox_fixnum
        at org.jruby.ir.persistence.IRReaderStream.decodeInstr(IRReaderStream.java:291)
        at org.jruby.ir.persistence.IRReaderStream.decodeInstructionsAt(IRReaderStream.java:173)
        at org.jruby.ir.persistence.IRReader.load(IRReader.java:54)
        at org.jruby.ir.runtime.IRRuntimeHelpers.decodeScopeFromBytes(IRRuntimeHelpers.java:1424)
        at test.loadIR(test.rb)
        ... 37 more
Exception `LoadError' at org/jruby/RubyKernel.java:939 - d:/temp/test.class is not compiled Ruby; use java_import to load normal classes
LoadError: d:/temp/test.class is not compiled Ruby; use java_import to load normal classes
  require at org/jruby/RubyKernel.java:939
  require at C:/jruby-9.0.3.0/lib/ruby/stdlib/rubygems/core_ext/kernel_require.rb:54
    <top> at -e:1