https://issues.dlang.org/show_bug.cgi?id=21283

          Issue ID: 21283
           Summary: [C++] Wrong mangling for ref of parameter pack
           Product: D
           Version: D2
          Hardware: All
                OS: Linux
            Status: NEW
          Keywords: C++, industry
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: pro.mathias.lang@gmail.com

C++ code:
```
template<typename T, typename ...Args>
void make_shared_poc (Args&... args) {}
template void make_shared_poc<int, int, int>(int&, int&);
```

Compiled with `g++ -std=c++11 test.cpp` gives:
```
$ nm test.o
0000000000000000 T __Z15make_shared_pocIiJiiEEvDpRT0_
```

Now the equivalent D code:
```
extern(C++) void make_shared_poc (T, Args...)  (ref Args args);
void foobar() { int a, b; make_shared_poc!(int, int, int)(a, b); }
```

Compiled with `dmd -extern-std=c++11 -c test.d` (DMD v2.094.0):
```
                 U __Z15make_shared_pocIiJiiEEvRDpT0_
```

Notice that in the C++ code, `R` comes after `Dq` (ref is part of the type),
while in the D code, `R` comes before.
See https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.function-type :
> When a function parameter is a C++11 function parameter pack, its type is mangled with Dp <type>, i.e., its type is a pack expansion:
> 
> <type>  ::= Dp <type>          # pack expansion (C++11)

--