Thanks for your bug report. In your last example, your use of { } in that context is technically not a valid use of those brackets, which were meant to be used with if/while. These really should report an error and halt the script but were left as-is for backward compatibility reasons long ago.
As for your other examples, you are certainly pushing the scripting language beyond its limits. As I have explained many times before, the scripting language was not designed, it grew organically over 25 years. It is amazing that the parser works as well as it does. It has many quirks, which have been discussed many times before. As much as I would love to see it working perfectly, the odds are that it will need a complete redesign to make it work correctly in the examples that you have provided, where you are mixing a large number of if/while/goto/brackets/separators/splits/etc. on one, long single line.
That said, I have added these examples to my to-do list.
