--- a/re2/re2.h	(index)
+++ a/re2/re2.h	(working tree)
@@ -280,6 +280,8 @@ class RE2 {
 #endif
   RE2(absl::string_view pattern);
   RE2(absl::string_view pattern, const Options& options);
+  // ambiguity resolution.
+  RE2(const TString& pattern) : RE2(StringPiece(pattern)) {}
   ~RE2();
 
   // Returns whether RE2 was created properly.