Error: 'xxx' is not a type

In this complete code:

class foo
{
  public:
    foo(const int pin);
};

class bar {
  public:
    // Constructor
    bar(const int dataPin) : dataPin_ (dataPin) { }

  private:
    const int dataPin_;
    foo myFoo_ (dataPin_);  // instance of foo
};

int main (void)
  {
  return 0;
  }

Using g++ 4.8.4 I get the error:

g++ -Wall -c "test.cpp" (in directory: /home/nick/Development)
test.cpp:14:17: error: ‘dataPin_’ is not a type
     foo myFoo_ (dataPin_);  // instance of foo
                 ^
Compilation failed.

Using clang 3.4-1ubuntu3 I get:

test.cpp:14:17: error: unknown type name 'dataPin_'
    foo myFoo_ (dataPin_);  // instance of foo
                ^
1 error generated.

Why does it want a type here? This is attempting to create an instance of foo as a class variable of bar. The variable dataPin_ is declared directly above.

---

If I change the line with the error to this, it compiles cleanly:

    foo myFoo_ (int dataPin_);  // instance of foo