1 files changed, 4 insertions, 1 deletions
diff --git a/lib/Sema/CXXFieldCollector.h b/lib/Sema/CXXFieldCollector.h
index 69d1351..63c6ee3 100644
--- a/lib/Sema/CXXFieldCollector.h
+++ b/lib/Sema/CXXFieldCollector.h
@@ -58,7 +58,10 @@ public:
   }
 
   /// getCurNumField - The number of fields added to the currently parsed class.
-  size_t getCurNumFields() const { return FieldCount.back(); }
+  size_t getCurNumFields() const {
+    assert(!FieldCount.empty() && "no currently-parsed class");
+    return FieldCount.back();
+  }
 
   /// getCurFields - Pointer to array of fields added to the currently parsed
   /// class.