Update cpp/src/arrow/compute/expression.cc

Co-authored-by: Rossi Sun <[email protected]>

Author: mroz45

cpp/src/arrow/compute/expression.cc

@@ -220,6 +220,7 @@ void PrintTo(const Expression& expr, std::ostream* os) {
 
 bool Expression::Equals(const Expression& other) const {
   if (Identical(*this, other)) return true;
+
   if (impl_ == nullptr || other.impl_ == nullptr) return false;
 
   if (impl_->index() != other.impl_->index()) {