[Bug libstdc++/28414] New: return type of valarray's sqrt function isn't valarray

["djg at cray dot com" <gcc-bugzilla at gcc dot gnu dot org>]

The return type of valarray's sqrt function isn't valarray, as specified in 
26.3.3.3 [lib.valarray.transcend], and what it does return doesn't convert to
valarray in some cases. This causes the slice1.cpp example from the Josuttis 
book examples to get a compile error:

http://www.josuttis.com/libbook/num/slice1.cpp.html

g++ gives this error:

slice1.cpp:48: error: no matching function for call to
?printValarray(std::_Expr<std::_UnClos<std::__sqrt, std::_ValArray, double>,
double>)?

Here's a reduced form which still shows the error:

#include <valarray>
using namespace std;

template<class T>
void printValarray (const valarray<T>& va);

void foo(void)
{
    valarray<double> v;

    printValarray (sqrt(v));
}


-- 
           Summary: return type of valarray's sqrt function isn't valarray
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: djg at cray dot com
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28414