4 fail_compilation/cppmangle.d(11): Error: expected valid identifier for C++ namespace but got ``
5 fail_compilation/cppmangle.d(15): Error: expected valid identifier for C++ namespace but got `0num`
6 fail_compilation/cppmangle.d(19): Error: compile time string constant (or sequence) expected, not `2`
7 fail_compilation/cppmangle.d(23): Error: expected valid identifier for C++ namespace but got `invalid@namespace`
23 extern(C
++, "invalid@namespace")