diff --git a/utils/TableGen/TGParser.cpp b/utils/TableGen/TGParser.cpp
index 7bd2fbcd930..22afca1ceb3 100644
--- a/utils/TableGen/TGParser.cpp
+++ b/utils/TableGen/TGParser.cpp
@@ -2087,7 +2087,8 @@ bool TGParser::ParseDefm(MultiClass *CurMultiClass) {
 ///   Object ::= LETCommand Object
 bool TGParser::ParseObject(MultiClass *MC) {
   switch (Lex.getCode()) {
-  default: assert(0 && "This is not an object");
+  default:
+    return TokError("Expected class, def, defm, multiclass or let definition");
   case tgtok::Let:   return ParseTopLevelLet(MC);
   case tgtok::Def:   return ParseDef(MC);
   case tgtok::Defm:  return ParseDefm(MC);