@Override
    public boolean fastEquals(TreeNode o) {
        if (this == o) {
            return true;
        }
        if (o instanceof AttributeReference) {
            AttributeReference other = (AttributeReference) o;
            return this.name.equals(other.name) && this.dataType.equals(other.dataType)
                    && this.metadata.equals(other.metadata) && this.exprId == other.exprId;
        }
        return false;
    }
Returns true iff the expression id is the same for both attributes.
indexr-query-opt/src/main/java/io/indexr/query/expr/attr/AttributeReference.java