diff --git a/compiler/cpp/src/thriftl.ll b/compiler/cpp/src/thriftl.ll
index 762cb2f..c3d577e 100644
--- a/compiler/cpp/src/thriftl.ll
+++ b/compiler/cpp/src/thriftl.ll
@@ -59,6 +59,11 @@
   exit(1);
 }
 
+void unexpected_token(char* text) {
+  yyerror("Unexpected token in input: \"%s\"\n", text);
+  exit(1);
+}
+
 %}
 
 /**
@@ -357,6 +362,10 @@
   }
 }
 
+. {
+  unexpected_token(yytext);
+}
+
 
 . {
   /* Catch-all to let us catch "*" in the parser. */