type narrowing for pxd files

Cython/Compiler/Symtab.py

@@ -1074,8 +1074,6 @@ class CClassScope(ClassScope):
             else:
                 if defining and entry.func_cname:
                     error(pos, "'%s' already defined" % name)
-                if not entry.type.same_as(type, as_cmethod = 1):
-                    old_type = entry.type
                 if type.narrower_c_signature_than(entry.type, as_cmethod = 1):
                     entry.type = type
                 else: