diff --git a/lib/VMCore/ModuleProvider.cpp b/lib/VMCore/ModuleProvider.cpp
index 7add84b0cb6..cbc82369a00 100644
--- a/lib/VMCore/ModuleProvider.cpp
+++ b/lib/VMCore/ModuleProvider.cpp
@@ -20,8 +20,7 @@ ModuleProvider::~ModuleProvider() {
 /// materializeFunction - make sure the given function is fully read.
 ///
 Module* ModuleProvider::materializeModule() {
-  // FIXME: throw an exception instead?
-  if (!TheModule) return 0;
+  assert(TheModule && "Attempting to materialize an invalid module!");
 
   for (Module::iterator i = TheModule->begin(), e = TheModule->end();
        i != e; ++i)