diff --git a/Cython/Compiler/Scanning.pxd b/Cython/Compiler/Scanning.pxd
index 792c9a1e1e51b511a5d6bea1c913e8603bd96713..4d298ec79fd22022c67467a23be48ef32ecd8ef8 100644
--- a/Cython/Compiler/Scanning.pxd
+++ b/Cython/Compiler/Scanning.pxd
@@ -8,6 +8,7 @@ cdef class Method:
     cdef object name
     cdef object __name__
 
+@cython.final
 cdef class CompileTimeScope:
     cdef public dict entries
     cdef public CompileTimeScope outer
@@ -15,6 +16,7 @@ cdef class CompileTimeScope:
     cdef lookup_here(self, name)
     cpdef lookup(self, name)
 
+@cython.final
 cdef class PyrexScanner(Scanner):
     cdef public context
     cdef public list included_files