Class: CleanBlockClosure Experimental This is disabled by default. If you want to experiment, you can enable the #optionCleanBlockClosure compiler option.
In the current system (with that option disabled), blocks are compiled to instances of CompiledBlock. They are stored as literals and we create/push a FullBlockClosure with a special bytecode.
This bytecode thus creates a FullBock at runtime. If a block is clean (does not access self, super, outer temps/args, does not return), we can create the block at compile time instead.
CleanBlockClosure is exactly that: a closure created at compile time, it is stored in the literal frame and just pushed on the stack. For debugging, it does implement all needed machinary to read temps (via tempNamed:) just like a FullBlockClosure