diff --git a/re2/regexp.cc b/re2/regexp.cc
index 7bb8390..99e72e5 100644
--- a/re2/regexp.cc
+++ b/re2/regexp.cc
@@ -678,7 +678,7 @@
       }
       break;
   }
-  *foldcase = (sub[i]->parse_flags() & FoldCase);
+  *foldcase = (sub[i]->parse_flags() & FoldCase) != 0;
   i++;
 
   // The rest.