This class is an ugly placeholder to handle the fact that sometimes The compiler creates an OpcodePush that uses relocatable DestinationLabels as a temporary place to store their arguments in the list until they get added to the program. Basically, it's this: Old way: 1. In some cases, like setting up locks, Compiler would create an OpcodePush with Argument = null, and a DestinationLabel = something. 2. ProgramBuilder would rebuild the OpcodePush's Argument by copying it from the DestinationLabel as part of ReplaceLabels at runtime. The Problem: When storing this in the ML file, BOTH the Argument AND the DestinationLabel would need to be stored as [MLFields] even though they are never BOTH populated at the same time, which causes ridiculous bloat. New Way: 1. Compiler creates an OpcodePushRelocateLater with a DestinationLabel = something. 2. ProgramBuilder replaces this with a normal OpcodePush who's argument is set to the relocated value of the DestinationLabel. Why: This way the MLFile only stores 1 argument: If it's an OpcodePush, it stores OpcodePush.Argument. If it's an OpcodePushRelocateLater, then it stores just OpcodePushRelocateLater.DestinationLabel and no argument.
