Add dependencies to type variables used in the super type declaration, but do

pkg/compiler/lib/src/deferred_load.dart

Index: pkg/compiler/lib/src/deferred_load.dart
diff --git a/pkg/compiler/lib/src/deferred_load.dart b/pkg/compiler/lib/src/deferred_load.dart
index fe9a4731edb41b6c4a3165dc2a876a4fb0ccfd1d..6fbe687bbaab24208b61cbcc28aacc61ff283458 100644
--- a/pkg/compiler/lib/src/deferred_load.dart
+++ b/pkg/compiler/lib/src/deferred_load.dart
@@ -319,9 +319,7 @@ class DeferredLoadTask extends CompilerTask {
         elements.add(type.element);
         collectTypeDependencies(type.unaliased);
       } else if (type is ResolutionInterfaceType) {
-        if (elements.add(type.element)) {
-          collectTypeDependencies(type.element.supertype);
-        }
+        elements.add(type.element);
       }
     }
 
@@ -456,11 +454,16 @@ class DeferredLoadTask extends CompilerTask {
       }
 
       ClassElement cls = element.declaration;
-      cls.implementation.forEachMember(addLiveInstanceMember);
-      for (ResolutionInterfaceType type in cls.implementation.allSupertypes) {
+      ClassElement implementation = cls.implementation;
+      implementation.forEachMember(addLiveInstanceMember);
+      var supertype = implementation.supertype;
+      if (supertype is GenericType) {
+        supertype.typeArguments.forEach(collectTypeDependencies);
+      }
+      for (ResolutionInterfaceType type in implementation.allSupertypes) {
         elements.add(type.element.implementation);

[sra1, 2017/08/11 21:55:46]

I think we need types from all supertypes to ensure they are available for the
$asX functions.

[Siggi Cherem (dart-lang), 2017/08/11 22:08:15]

Done. Also added a test with an `is` check. We should be good now.

       }
-      elements.add(cls.implementation);
+      elements.add(implementation);
     } else if (Elements.isStaticOrTopLevel(element) || element.isConstructor) {
       elements.add(element);
       collectDependencies(element);