visitMax must be in generated ASMifier code
When disabling show local variables, the mv.visitMaxs(?,?) call is omitted from the generated code in ASMifier view. These calls are necessary for the generated code to produce a valid class file. Otherwise, the stack size and local variable size is set to zero and the VM rejects the class file. If my guess is correct that CommentedASMifierClassVisitor generates the code, the "if(showLocals)" check in visitMaxs should probably not be there.