CodeQL library for C#
codeql/csharp-all 1.0.3-dev (changelog, source)

Member predicate LEExpr::getLesserOperand

Gets the operand on the “lesser” (or “lesser-or-equal”) side of this relational expression, that is, the side that is smaller if the overall expression evaluates to true; for example on x <= 20 this is x, and on y > 0 it is the 0.

Expr getLesserOperand()