complete/resolve members of 'type' type on definitions of new-style classes (PY-3989)

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

@@ -175,6 +175,15 @@ public class PyClassType extends UserDataHolderBase implements PyType {
         }
       }
     }
+    if (isDefinition() && myClass.isNewStyleClass()) {
+      PyClassType typeType = PyBuiltinCache.getInstance(myClass).getObjectType("type");
+      if (typeType != null) {
+        List<? extends RatedResolveResult> typeMembers = typeType.resolveMember(name, location, direction, resolveContext);
+        if (typeMembers != null && !typeMembers.isEmpty()) {
+          return typeMembers;
+        }
+      }
+    }
     return Collections.emptyList();
   }
 
@@ -238,6 +247,13 @@ public class PyClassType extends UserDataHolderBase implements PyType {
 
     addInheritedMembers(prefix, location, context, ret);
 
+    if (isDefinition() && myClass.isNewStyleClass()) {
+      PyClassType typeType = PyBuiltinCache.getInstance(myClass).getObjectType("type");
+      if (typeType != null) {
+        Collections.addAll(ret, typeType.getCompletionVariants(prefix, location, context));
+      }
+    }
+
     return ret.toArray();
   }
 

python/testData/completion/mro.after.py

@@ -0,0 +1,5 @@
+class C(object):
+    pass
+
+
+C.__mro__

python/testData/completion/mro.py

@@ -0,0 +1,5 @@
+class C(object):
+    pass
+
+
+C.__m<caret>

python/testData/inspections/PyUnresolvedReferencesInspection/mro.py

@@ -0,0 +1,3 @@
+class C(object): pass
+
+C.__mro__

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

@@ -392,4 +392,8 @@ public class PythonCompletionTest extends PyLightFixtureTestCase {
   public void testDuplicateColon() {  // PY-2652
     doTest();
   }
+
+  public void testMro() {  // PY-3989
+    doTest();
+  }
 }

python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java

@@ -36,6 +36,10 @@ public class PyUnresolvedReferencesInspectionTest extends PyLightFixtureTestCase
     doTest();
   }
 
+  public void testMro() {  // PY-3989
+    doTest();
+  }
+
   public void testConditionalImports() { // PY-983
     myFixture.configureByFiles(TEST_DIRECTORY + getTestName(true) + ".py",
                                TEST_DIRECTORY + "lib1.py",