DarwinGCC.qbs:48:45 TypeError: Result of expression 'product.type' [undefined] is not an object.

No such expression on that line. Obviously this indicates bugs in error handling not giving the right source location, too.

The cause of this problem was that I had a Product which depended on Qt and whose type was not set. Shouldn't the default Product type be [], not undefined? There should be a better error message for something like this.