use iterateNames() for gathering completion variants of a module type

python/src/com/jetbrains/python/psi/types/PyModuleType.java

@@ -122,7 +122,9 @@ public class PyModuleType implements PyType { // Modules don't descend from obje
         }
       }, new PyUtil.UnderscoreFilter(0));
       processor.setPlainNamesOnly(point  == ResolveImportUtil.PointInImport.AS_NAME); // no parens after imported function names
-      myModule.processDeclarations(processor, ResolveState.initial(), null, location);
+      for(PyElement element: myModule.iterateNames()) {
+        processor.execute(element, ResolveState.initial());
+      }
       if (names_already != null) {
         for (LookupElement le : processor.getResultList()) {
           String name = le.getLookupString();

python/testData/completion/dunderAll/a.after.py

@@ -0,0 +1,3 @@
+import importSource
+
+importSource.xyzzy

python/testData/completion/dunderAll/a.py

@@ -0,0 +1,3 @@
+import importSource
+
+importSource.xy<caret>

python/testData/completion/dunderAll/importSource.py

@@ -0,0 +1,2 @@
+__all__ = ['xyzzy', 'shazam']
+

python/testSrc/com/jetbrains/python/PythonCompletionTest.java

@@ -487,4 +487,8 @@ public class PythonCompletionTest extends PyTestCase {
   public void testAssignedNearby() {
     doTest();
   }
+  
+  public void testDunderAll() {
+    doMultiFileTest();
+  }
 }