Types declared in a foreign package are processed one at a time

The following snippet has two issues

package a;
declare b.X  field : b.Y end
declare b.Y end

While processing package a, the packageBuilder will infer the existence of package b and create the appropriate typeDeclarations.
However, a partial, independent package b is created for X and Y:

• it is inefficient
• internal dependencies cannot be resolved : b.X does not (yet) see b.Y