pub fn flip_comparison_binop(expr: &Spanned<Expr>) -> Option<Spanned<Expr>>Expand description
Flip a comparison BinOp to its logical negation so a caller’s
match (a OP b) { false -> ... } arm normalises into a positive
predicate. Returns None for non-comparison operators (Add,
Sub, etc.) — those can’t legally land as a match … { Bool -> ... } subject anyway. Used by the issue-84 caller-guard extractor
so every collected predicate is the same Spanned<Expr> shape
opaque types and verify when already use, avoiding a parallel
(expr, negated) representation.