MatchExpression::parameterize() returns a vector of MatchExpression pointers by value. But its return value is not eligible for NRVO because it is a field of a local variable, not the local variable itself:

std::vector<const MatchExpression*> MatchExpression::parameterize(MatchExpression* tree) {
    MatchExpressionParameterizationVisitorContext context{};
    MatchExpressionParameterizationVisitor visitor{&context};
    MatchExpressionParameterizationWalker walker{&visitor};
    tree_walker::walk<false, MatchExpression>(tree, &walker);
    return context.inputParamIdToExpressionMap;
}

a std::move() on the return value will avoid a copy.

see src/mongo/db/matcher/expression.cpp

Likewise, nss() makes a copy with every call, which is unnecessary. Since isQuerySbeCompatible() is in the hot path, let's avoid copying when we can.

see src/mongo/db/query/query_utils.cpp