Return next after Base in self's MRO for super(Base, self) (PY-32533)

Previously first class in `Base`'s MRO were returned.

python/src/com/jetbrains/python/psi/impl/PyCallExpressionHelper.java

@@ -659,9 +659,15 @@ public class PyCallExpressionHelper {
           return getSuperClassUnionType(firstClass, context);
         }
         if (secondClass.isSubclass(firstClass, context)) {
-          final Iterator<PyClass> iterator = firstClass.getAncestorClasses(context).iterator();
-          if (iterator.hasNext()) {
-            return new PyClassTypeImpl(iterator.next(), false); // super(Foo, self) has type of Foo, modulo __get__()
+          final PyClass nextAfterFirstInMro = StreamEx
+            .of(secondClass.getAncestorClasses(context))
+            .dropWhile(it -> it != firstClass)
+            .skip(1)
+            .findFirst()
+            .orElse(null);
+
+          if (nextAfterFirstInMro != null) {
+            return new PyClassTypeImpl(nextAfterFirstInMro, false);
           }
         }
       }

python/testSrc/com/jetbrains/python/PyTypeTest.java

@@ -3294,6 +3294,30 @@ public class PyTypeTest extends PyTestCase {
            "   expr = a");
   }
 
+  // PY-32533
+  public void testSuperWithAnotherType() {
+    runWithLanguageLevel(
+      LanguageLevel.PYTHON34,
+      () -> doTest("A",
+                   "class A:\n" +
+                   "    def f(self):\n" +
+                   "        return 'A'\n" +
+                   "\n" +
+                   "class B:\n" +
+                   "    def f(self):\n" +
+                   "        return 'B'\n" +
+                   "\n" +
+                   "class C(B):\n" +
+                   "    def f(self):\n" +
+                   "        return 'C'\n" +
+                   "\n" +
+                   "class D(C, A):\n" +
+                   "    def f(self):\n" +
+                   "        expr = super(B, self)\n" +
+                   "        return expr.f()")
+    );
+  }
+
   private static List<TypeEvalContext> getTypeEvalContexts(@NotNull PyExpression element) {
     return ImmutableList.of(TypeEvalContext.codeAnalysis(element.getProject(), element.getContainingFile()).withTracing(),
                             TypeEvalContext.userInitiated(element.getProject(), element.getContainingFile()).withTracing());