More small fixes

from_cpython/Lib/_abcoll.py

@@ -23,7 +23,9 @@ __all__ = ["Hashable", "Iterable", "Iterator",
 
 def _hasattr(C, attr):
     try:
-        return any(attr in B.__dict__ for B in C.__mro__)
+        # Pyston temporary workaround: make this a list comprehension instead of generator comprehension,
+        # since any() can exit without exhausting the iterable.
+        return any([attr in B.__dict__ for B in C.__mro__])
     except AttributeError:
         # Old-style class
         return hasattr(C, attr)

src/runtime/str.cpp

@@ -2590,6 +2590,7 @@ extern "C" void PyString_Concat(register PyObject** pv, register PyObject* w) no
 
 extern "C" void PyString_ConcatAndDel(register PyObject** pv, register PyObject* w) noexcept {
     PyString_Concat(pv, w);
+    Py_XDECREF(w);
 }
 
 static PyObject* string_expandtabs(PyStringObject* self, PyObject* args) noexcept {

src/runtime/types.h

@@ -1385,7 +1385,7 @@ inline BORROWED(Box*) Box::getattrString(const char* attr) {
 inline void ExcInfo::clear() {
     Py_DECREF(type);
     Py_DECREF(value);
-    Py_DECREF(traceback); // XDECREF?
+    Py_XDECREF(traceback);
 }
 } // namespace pyston