Function resolve_local_columns 

fn resolve_local_columns(
    expr: &HirScalarExpr,
    env: &[HirScalarExpr],
) -> Option<HirScalarExpr>

Returns expr with every reference to the current scope (a ColumnRef with level == 0) replaced by its value from env. Returns None if expr cannot be soundly lifted into the outer scope, or references a column absent from env.