Inf outside of representable range of type 'int' in sugar functions

[Enchufa2]

Again, from the full test suite under the UBSAN container, as reported by @eddelbuettel:

test_sugar.R..................  452 tests OK /usr/local/lib/R/site-library/Rcpp/include/Rcpp/sugar/functions/min.h:36:53: runtime error: inf is outside the range of representable values of type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/local/lib/R/site-library/Rcpp/include/Rcpp/sugar/functions/min.h:36:53 
test_sugar.R..................  454 tests OK /usr/local/lib/R/site-library/Rcpp/include/Rcpp/sugar/functions/max.h:36:53: runtime error: -inf is outside the range of representable values of type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/local/lib/R/site-library/Rcpp/include/Rcpp/sugar/functions/max.h:36:53

Same issue: we are returning R_PosInf/R_NegInf if the object has no elements:

Rcpp/inst/include/Rcpp/sugar/functions/max.h

Lines 32 to 47 in 7ff6ba2

	Max( const T& obj_) : obj(obj_) {}
	operator STORAGE() const {
	R_xlen_t n = obj.size();
	if (n == 0) return(static_cast<STORAGE>(R_NegInf));
	STORAGE max, current ;
	max = obj[0] ;
	if( Rcpp::traits::is_na<RTYPE>( max ) ) return max ;
	for( R_xlen_t i=1; i<n; i++){
	current = obj[i] ;
	if( Rcpp::traits::is_na<RTYPE>( current ) ) return current;
	if( current > max ) max = current ;
	}
	return max ;
	}

So one possible approach would be similar to this one:

Rcpp/inst/include/Rcpp/sugar/operators/Comparator_With_One_Value.h

Lines 36 to 43 in 7ff6ba2

	Comparator_With_One_Value( const VEC_TYPE& lhs_, STORAGE rhs_ ) :
	lhs(lhs_), rhs(rhs_), m(), op() {
	m = Rcpp::traits::is_na<RTYPE>(rhs) ?
	&Comparator_With_One_Value::rhs_is_na :
	&Comparator_With_One_Value::rhs_is_not_na ;
	}

I.e., check the object size on object creation and assign the proper operator: one that returns a double with infinity if the object has no elements, or one that returns STORAGE with the computed min/max.

Maybe there's a more sophisticated solution using std::enable_if.