presto-main/src/main/java/io/prestosql/sql/planner/ReferenceAwareExpressionNodeInliner.java/ReferenceAwareExpressionNodeInliner/ReferenceAwareExpressionNodeInliner
class ReferenceAwareExpressionNodeInliner:    private ReferenceAwareExpressionNodeInliner(Map<NodeRef<Expression>, Expression> mappings)
    {
        this.mappings = ImmutableMap.copyOf(requireNonNull(mappings, "mappings is null"));
    }