Strange behavior with constexpr static member variable

Question

This is a follow up question to Undefined reference to static constexpr char[][].

The following program builds and runs fine.

#include <iostream>

struct A {
   constexpr static char dict[] = "test";

   void print() {
      std::cout << A::dict[0] << std::endl;
   }
};

int main() {
   A a;
   a.print();
   return 0;
}

However, if I change A::print() to:

   void print() {
      std::cout << A::dict << std::endl;
   }

I get the following linker error in g++ 4.8.2.

/tmp/cczmF84A.o: In function `A::print()':
socc.cc:(.text._ZN1A5printEv[_ZN1A5printEv]+0xd): undefined reference to `A::dict'
collect2: error: ld returned 1 exit status

The linker error can be resolved by adding a line:

constexpr char A::dict[];

outside the class definition.

However, it's not clear to me why using one of the members of the array does not cause a linker error while using the array causes a linker error.