Index: utils/lit/lit/TestingConfig.py
===================================================================
--- utils/lit/lit/TestingConfig.py
+++ utils/lit/lit/TestingConfig.py
@@ -152,3 +152,16 @@
         else:
             return self.parent.root

+class SubstituteCaptures:
+    '''
+    Helper class to indicate that the substitutions contains backreferences.
+    '''
+    def __init__(self, substitution):
+        self.substitution = substitution
+
+    def replace(self, pattern, replacement):
+        return self.substitution
+
+    def __str__(self):
+        return self.substitution
+