Fix list membership test

_list.pxd

@@ -19,3 +19,11 @@ cdef extern from * nogil:
         list_iterator_t operator++()
         bint operator!=(base_iterator_t)
 
+
+# Needed to implement "value in list" test for template list
+cdef extern from "<functional>" namespace "std" nogil:
+    cdef cppclass equal_to[T=*]:
+        # https://github.com/cython/cython/issues/3193
+        equal_to() except +
+        bint operator()(const T& lhs, const T& rhs) except +
+

list.pxd

@@ -118,7 +118,7 @@ cdef cypclass List[V]:
 
     bint __contains__(const self, const value_type value):
         for v in self._elements:
-            if value is v:
+            if equal_to[value_type]()(value, v):
                 return 1
         return 0