diff --git a/re2/prog.cc b/re2/prog.cc
index 5dc7f82..3166f2b 100644
--- a/re2/prog.cc
+++ b/re2/prog.cc
@@ -349,7 +349,7 @@
 
  private:
   bool Get(int c) const {
-    return words_[c >> 6] & (1ULL << (c & 63));
+    return (words_[c >> 6] & (1ULL << (c & 63))) != 0;
   }
 
   void Set(int c) {