variant of non-const references fails equality compare

[nikkoara@…]

The following aborts:

#include <boost/variant.hpp>

using variant_type = boost::variant< int& >;

int main () {
    int a, b;

    variant_type v (a), u (b);
    v == u;

    return 0;
}

Compile and run:

$ g++ -std=c++14 -I/opt/boost/default/include t.cpp && ./a.out 
a.out: /opt/boost/default/include/boost/variant/detail/forced_return.hpp:39: T boost::detail::variant::forced_return() [with T = const int&]: Assertion `false' failed.
Aborted (core dumped)

It seems that the cause is the instantiation of known_get for const T at line 905 in variant.hpp (1.59.0).

[Antony Polukhin]

Fixed in ​082732aa develop, will be merged to master as soon as the tests will cycle.