Fix deferred load errors / bug #26482

runtime/lib/lib_prefix.dart

Index: runtime/lib/lib_prefix.dart
diff --git a/runtime/lib/lib_prefix.dart b/runtime/lib/lib_prefix.dart
index 9d5af287e9e25e79f56e8ca99c2cb7e8318687c3..fb226718b8ec157e95fd7283002270fecbfeaf8e 100644
--- a/runtime/lib/lib_prefix.dart
+++ b/runtime/lib/lib_prefix.dart
@@ -10,6 +10,7 @@ class _LibraryPrefix {
   bool _load() native "LibraryPrefix_load";
   Error _loadError() native "LibraryPrefix_loadError";
   bool isLoaded() native "LibraryPrefix_isLoaded";
+  bool hasError() native "LibraryPrefix_hasError";
   bool _invalidateDependentCode()
       native "LibraryPrefix_invalidateDependentCode";
 
@@ -55,15 +56,14 @@ _completeDeferredLoads() {
   var stillOutstandingLoadRequests = new List<List>();
   for (int i = 0; i < _outstandingLoadRequests.length; i++) {
     var prefix = _outstandingLoadRequests[i][0];
-    if (prefix._load()) {
-      var completer = _outstandingLoadRequests[i][1];
+    var completer = _outstandingLoadRequests[i][1];
+    if (prefix.hasError()) {

[hausner, 2016/06/07 21:47:05]

I think you should use prefix._loadError() to determine whether there was an
error while loading. That function checks the library import graph transitively
for errors. 

[Cutch, 2016/06/07 22:29:26]

Done.

       var error = prefix._loadError();
-      if (error != null) {
-        completer.completeError(error);
-      } else {
-        prefix._invalidateDependentCode();
-        completer.complete(true);
-      }
+      assert(error != null);
+      completer.completeError(error);
+    } else if (prefix._load()) {
+      prefix._invalidateDependentCode();
+      completer.complete(true);
     } else {
       stillOutstandingLoadRequests.add(_outstandingLoadRequests[i]);
     }