Can `offsetof` be used with a type obtained through `decltype`? Is either of those cases valid C++11?

```
struct S {
  int i;
  int j { offsetof(decltype(*this), i) };  // case 1
  S() : i(offsetof(decltype(*this), j)) {}; // case 2
} inst1;

int main() {
  struct {
    int i;
    int j { offsetof(decltype(*this), i) }; // case 3
  } inst2;
  return 0;
}

```

None of it compiles under Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn), with the error

```
error: offsetof requires struct, union, or class type, 
'decltype(*this)' (aka '<anonymous struct at ../qxjs3uu/main.cpp:4:4> &') invalid

```

It also seems to crash MSVC 19.00.23106.0(x86) with an internal error:

```
Compiled with  /EHsc /nologo /W4 /c
main.cpp
main.cpp(3): error C2062: type 'S &' unexpected
[...]
main.cpp(4): fatal error C1903: unable to recover from previous error(s); stopping compilation
Internal Compiler Error in c:\tools_root\cl\bin\i386\cl.exe.  You will be prompted to send an error report to Microsoft later.

```

Did I think of something that no test case writers thought of?