Don't error on inherited type members.

This fixes #1788.

Cython/Compiler/Symtab.py

@@ -434,6 +434,9 @@ class Scope(object):
             if self.is_cpp_class_scope and type.is_cfunction and old_type.is_cfunction and type != old_type:
                 # C++ method overrides are ok
                 pass
+            elif self.is_cpp_class_scope and entries[name].is_inherited:
+                # Likewise ignore inherited classes.
+                pass
             elif visibility == 'extern':
                 warning(pos, "'%s' redeclared " % name, 0)
             elif visibility != 'ignore':

tests/run/cpp_stl_vector.pyx

@@ -210,3 +210,11 @@ def test_insert():
     assert v.size() == count
     for element in v:
         assert element == value, '%s != %s' % (element, count)
+
+
+#  Tests GitHub issue #1788.
+cdef cppclass MyVector[T](vector):
+    pass
+
+cdef cppclass Ints(MyVector[int]):
+    pass