Problem : Rule loader should reject unsupported logic edge cases

[akshat4703]

Problem

While experimenting with capa rule logic, I noticed that some rule constructs are currently accepted during rule loading even though they are not safe for the optimized matcher/indexer.

In particular, certain logical edge cases can lead to ambiguous or incorrect evaluation behavior.

Examples include:

• top-level not statements
• nested not constructs (e.g. not: not: ...)
• top-level count(...): 0 statements

These patterns may conflict with assumptions made by the optimized rule matcher and rule indexer.

Example

For example, a rule containing something like:

not:

  api: CreateFileA
Or
not:
  not:
    api: CreateFileA
Similarly, constructs like:
count(api(CreateFileA)): 0
may introduce ambiguity or unexpected behavior during rule evaluation.

Expected Behavior

Rules containing unsupported logic constructs should be rejected during rule loading with a clear validation error.

This would:
	•	prevent subtle evaluation bugs
	•	ensure rules remain compatible with the optimized matcher/indexer
	•	provide clearer feedback to rule authors when invalid constructs are used.

Related Work #2913 

[akshat4703]

@williballenthin @mike-hunhoff i would like to know about your thoughts on this. If you could tell me what you think about it