Add rule for detecting invalid logical expressions

[scripthunter7]

We should check conditions in if preprocessor directive.

A logical expression can be invalid if it is contradictory or always produces the same result regardless of the input. Here are some examples:

1. Self-Contradiction

• (A && !A)
  • This states that "A is true and A is not true" simultaneously, which is logically impossible.

2. Redundancy

• (A || A)
  • This always produces the same result as A. One of the conditions is unnecessary.

3. Unnecessary Expressions

• (A && true) or (A || false)
  • Such expressions are not logically invalid but redundant, as true or false does not change the outcome.

4. Always True (Tautology)

• (A || !A)
  • This is always true because either A is true, or A is not true (this is an axiom).

5. Disconnected Conditions

• (A && B && !B)
  • Here, B and !B exclude each other, so the entire expression will always be false, regardless of the value of A.