as of tools version 5.8, it appears that if the package id in a .product(name:package:) dependency descriptor is wrong, then SPM will refuse to build the package.
in the past, i recall SPM (tools version 5.7 or below) would simply ignore the package id, since its notion of product identity was simply the product name. it seems that now, product identity is the tuple (PackageID, ProductName).
does this mean that support for packages with products with the same names is on the horizon?