[BUG] Incorrect enum syntax crashes compiler

[JakeShirley]

Describe the bug I am still cludging my way around enums and typed in some nonsense. I got a really unhelpful message that doesn't help narrow down where the problem is.

To Reproduce

1. Compile this example:

   Operation : @enum type = {
   None = 0;
   LessThan = 1;
   GreaterThan = 2;
   }
   auto main() -> int {
   std::cout << "Hello ";
   }

2. See the following output:

   Bounds safety violation: out of bounds access attempt detected - attempted index 0, [min,max] range is [0,-1]
   terminate called without an active exception
   Program terminated with signal: SIGSEGV

Additional context Ideally cppfront would not crash. Or it would give a hint at where it was crashing.

[hsutter]

Thanks! Fixed.

That was Cpp2's on-by-default general subscript bounds checking catching a bug in self-hosted Cpp2 code that was indexing [0] on an empty container. I really like having bounds and null-deref checking on by default... I'm pretty careful about defensive checking, but seeing these bounds checks still catch bugs in my own code is a bit of an eye-opener.