[cfe-dev] Looks lie a bug: no implicit conversion from slice_array to valarray in 3.4.1 + libcpp

[Lev Serebryakov]

Hello, Cfe-dev.

 I'm using clang 3.4.1 (FreeBSD-CURRENT system compiler) with
 I'm compile very simple program, which uses <valarray>. Of course, it is
 test case, I found this bug when try to compile qucs project on this system

============ test.cpp
#include <valarray>

int main(int argc, char *argv[]) {
        std::valarray<double> a(4, 10);
        std::valarray<double> b(4, 20);
        a *= b[std::slice(1,1,1)];
        return 0;
}
=====================

I've got this error:

=================================================
test.cpp:6:4: error: no viable overloaded '*='
        a *= b[std::slice(1,1,1)];
        ~ ^  ~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/v1/valarray:871:15: note: candidate function not viable: no known conversion from 'slice_array<value_type>' to 'const value_type'
      (aka 'const double') for 1st argument
    valarray& operator*= (const value_type& __x);
              ^
/usr/include/c++/v1/valarray:885:9: note: candidate template ignored: disabled by 'enable_if' [with _Expr = std::__1::slice_array<double>]
        __is_val_expr<_Expr>::value,
        ^
=================================================

 Looks like, constructor valarray(const slice_array<double> &) should be
called in this case? I've read
http://en.cppreference.com/w/cpp/language/implicit_cast
 and looks like implicit conversion should apply here (second item in first
 list)?

 gcc 4.8 compiles this code properly.

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>