fixes #532

Author: guybedford

core/register-loader.js

@@ -358,7 +358,7 @@ function instantiateDeps (loader, load, link, registry, state, seen) {
     var depsInstantiatePromises = Array(link.dependencies.length);
 
     for (var i = 0; i < link.dependencies.length; i++)
-      depsInstantiatePromises[i] = resolveInstantiateDep(loader, link.dependencies[i], load.key, registry, state, loader.trace && (link.depMap = {}));
+      depsInstantiatePromises[i] = resolveInstantiateDep(loader, link.dependencies[i], load.key, registry, state, loader.trace && link.depMap || (link.depMap = {}));
 
     return Promise.all(depsInstantiatePromises);
   })