SIG11 crashing - can't figure it out

[via Digitalmars-d-learn]

Working my way through Ali Çehreli's rather amazing e-book, I've 
hit a snag where some code I've written is pretty crashy. I 
consistently get "Segmentation fault: 11" (dmd 2.067.1, OSX).

I can't figure out where things are going wrong, because any 
attempt I make to debug via extra print statements causes the 
program to run successfully. Same if I try to compile with "-gc" 
... it suddenly starts working, so I can't debug with gdb.

Putting aside any "that's probably not a great solution to the 
problem you're tying to solve" thoughts, can anyone offer me the 
"eureka" moment I'm missing to understand why the code below 
doesn't work?

Many thanks in advance!

* * *

import std.stdio;

enum Suit {
        HEARTS, DIAMONDS, CLUBS, SPADES
}

enum Value {
	ACE = 1, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN, 
JACK, QUEEN, KING
}

struct Card {
        Value value;
        Suit suit;
}

void printCard(in Card card) {
        final switch(card.value) {
                case Value.ACE:
                        write("A");
                        break;
		case Value.TWO, Value.THREE, Value.FOUR, Value.FIVE, Value.SIX, 
Value.SEVEN, Value.EIGHT, Value.NINE, Value.TEN:
                        writef("%d", card.value);
                        break;
                case Value.JACK:
                        write("J");
                        break;
                case Value.QUEEN:
                        write("Q");
                        break;
                case Value.KING:
                        write("K");
                        break;
        }
        final switch(card.suit) {
                case Suit.HEARTS:
                        write("♡");
                        break;
                case Suit.DIAMONDS:
                        write("♢");
                        break;
                case Suit.CLUBS:
                        write("♣");
                        break;
                case Suit.SPADES:
                        write("♠");
                        break;
        }
        write("\n");
}

int main() {
        auto card = Card(Value.JACK, Suit.CLUBS);
        printCard(card);
        return 0;
}