The scratch allocator could erroneously return a slice
overlapping previously allocated memory for allocation
requests that were smaller than the arena size, but larger
than the amount of free space left in the arena.
- fix the check in mem::scratch_alloc_bytes_non_zeroed
that wasn't routing the request to the backup allocator.
- added concrete reproduction test under tests/issues.
- when checking the variants of a union type we will skip adding
the variants if we have an unspecialized polymorphic, hence our
union_type variants will be empty and have a count of 0
- so when checking if we violate the #no_nil error, if we are in the
unspecialized polymorphic case and there exists at least one variant
in the original variants then we should not raise this error
- test checks that we do not raise the error anymore, and that we still
detect the #no_nil error in the described circumstances
- Introduce new `Path` type and an array of build paths on the build context.
- Resolve input and output paths/files early (before parsing).
- Error early if inputs are missing or outputs are directories.
- Plumb new file path generation into linker stage instead of its adhoc method.
TODO:
- Remove more adhoc file path generation in parser and linker stage.
- Make intermediate object file generation use new path system.
- Round out and robustify Path helper functions.
Inits `o->value` in `check_expr_base_internal()` so doesn't accidentally
use last (the proc lit was being set to that of previous string)
Adds test to "tests/issues" and changes CI to use new "run" shells
