lib/extensible/extension_kernel.rb in extensible-0.1.1 vs lib/extensible/extension_kernel.rb in extensible-0.1.2

@@ -6,18 +6,26 @@
   # A custom ExtensionKernelTemplate clone that is extended by Extensible to make it, well, extensible.
   ExtensionKernel = ExtensionKernelTemplate.clone.module_eval do
     private
 
     def extended(submodule)
+      raise_type_error_if_submodule_is_not_a_module(submodule)
+
       super
 
       unless Utils.own_const_defined?(submodule, :ExtensionKernel)
         kernel = ExtensionKernelTemplate.clone
         submodule.const_set(:ExtensionKernel, kernel)
         submodule.extend kernel
       end
 
       self
+    end
+
+    def raise_type_error_if_submodule_is_not_a_module(submodule)
+      return if submodule.class == Module
+      raise TypeError, "expected to extend object of type `Module` with module `#{name}`, got `#{submodule.class}` " \
+                       "instead"
     end
 
     self
   end
 end