[mlir][python] Fix build on windows

[Mogball]

clang-format

[ashay-github]

LGTM, thanks for the quick fix!

[stella.stamenova]

It looks like this addresses the failure.

mlir/lib/Bindings/Python/IRAttributes.cpp

std::string msg = std::string("Invalid attribute (None?) when attempting "
                       err.what() + ")";
     throw py::cast_error(msg);
   }
 }
 
 /// A python-wrapped dense array attribute with an element type and a derived
 /// implementation class.
 template <typename EltTy, typename DerivedT>
-class PyDenseArrayAttribute
-    : public PyConcreteAttribute<PyDenseArrayAttribute<EltTy, DerivedT>> {
+class PyDenseArrayAttribute : public PyConcreteAttribute<DerivedT> {
 public:
-  static constexpr typename PyConcreteAttribute<
-      PyDenseArrayAttribute<EltTy, DerivedT>>::IsAFunctionTy isaFunction =
-      DerivedT::isaFunction;
-  static constexpr const char *pyClassName = DerivedT::pyClassName;
-  using PyConcreteAttribute<
-      PyDenseArrayAttribute<EltTy, DerivedT>>::PyConcreteAttribute;
+  using PyConcreteAttribute<DerivedT>::PyConcreteAttribute;
 
   /// Iterator over the integer elements of a dense array.
   class PyDenseArrayIterator {
   public:
     PyDenseArrayIterator(PyAttribute attr) : attr(attr) {}
 
     /// Return a copy of the iterator.
     PyDenseArrayIterator dunderIter() { return *this; }
private:
     /// The next index to read.
     int nextIndex = 0;
   };
 
   /// Get the element at the given index.
   EltTy getItem(intptr_t i) { return DerivedT::getElement(*this, i); }
 
   /// Bind the attribute class.
-  static void bindDerived(typename PyConcreteAttribute<
-                          PyDenseArrayAttribute<EltTy, DerivedT>>::ClassTy &c) {
+  static void bindDerived(typename PyConcreteAttribute<DerivedT>::ClassTy &c) {
     // Bind the constructor.
     c.def_static(
         "get",
         [](const std::vector<EltTy> &values, DefaultingPyMlirContext ctx) {
           MlirAttribute attr =
               DerivedT::getAttribute(ctx->get(), values.size(), values.data());
-          return PyDenseArrayAttribute<EltTy, DerivedT>(ctx->getRef(), attr);
+          return DerivedT(ctx->getRef(), attr);
         },
         py::arg("values"), py::arg("context") = py::none(),
         "Gets a uniqued dense array attribute");
     // Bind the array methods.
-    c.def("__getitem__",
-          [](PyDenseArrayAttribute<EltTy, DerivedT> &arr, intptr_t i) {
-            if (i >= mlirDenseArrayGetNumElements(arr))
-              throw py::index_error("DenseArray index out of range");
-            return arr.getItem(i);
-          });
-    c.def("__len__", [](const PyDenseArrayAttribute<EltTy, DerivedT> &arr) {
+    c.def("__getitem__", [](DerivedT &arr, intptr_t i) {
+    c.def("__len__", [](const DerivedT &arr) {
       return mlirDenseArrayGetNumElements(arr);
     });
-    c.def("__iter__", [](const PyDenseArrayAttribute<EltTy, DerivedT> &arr) {
-      return PyDenseArrayIterator(arr);
-    });
-    c.def("__add__", [](PyDenseArrayAttribute<EltTy, DerivedT> &arr,
-                        py::list extras) {
+    c.def("__iter__",
+          [](const DerivedT &arr) { return PyDenseArrayIterator(arr); });
+    c.def("__add__", [](DerivedT &arr, py::list extras) {
       std::vector<EltTy> values;
       intptr_t numOldElements = mlirDenseArrayGetNumElements(arr);
       values.reserve(numOldElements + py::len(extras));
       for (intptr_t i = 0; i < numOldElements; ++i)
         values.push_back(arr.getItem(i));
       for (py::handle attr : extras)
         values.push_back(pyTryCast<EltTy>(attr));
       MlirAttribute attr = DerivedT::getAttribute(arr.getContext()->get(),
                                                   values.size(), values.data());
-      return PyDenseArrayAttribute<EltTy, DerivedT>(arr.getContext(), attr);
+      return DerivedT(arr.getContext(), attr);
     });
   }
 };
 
 /// Instantiate the python dense array classes.
 struct PyDenseBoolArrayAttribute
     : public PyDenseArrayAttribute<int, PyDenseBoolArrayAttribute> {
   static constexpr IsAFunctionTy isaFunction = mlirAttributeIsADenseBoolArray;