C++17: Nested Namespaces

Another crowd-pleaser in C++17 is the ability to declared nested namespaces without literally nesting them. In the past, you had to do this, which involves a lot of wasted whitespace:

namespace NestedNamespaces
{
    namespace Really
    {
        namespace Work
        {
            auto return_int(){ return 42; };
        }
    }
}

Happily, you can now do this instead:

namespace NestedNamespaces::Really::Work
{
    auto return_int(){ return 42; };
}

TEST( Cpp17, nested_namespaces )
{
    EXPECT_EQ( 42, NestedNamespaces::Really::Work::return_int() );
}

See also previous C++17 post.