diff --git a/compiler2/ttcn3/PatternString.cc b/compiler2/ttcn3/PatternString.cc
index 0d2dd3bef5a6c4be91c56ab4ce4c1e669a0905dc..15e1d15a81cca3bdb9ad961cf2fcb4d57ab17b63 100644
--- a/compiler2/ttcn3/PatternString.cc
+++ b/compiler2/ttcn3/PatternString.cc
@@ -276,7 +276,7 @@ namespace Ttcn {
   // =================================
 
   PatternString::PatternString(const PatternString& p)
-    : Node(p), my_scope(0), pattern_type(p.pattern_type)
+    : Node(p), my_scope(0), cstr_value(0), pattern_type(p.pattern_type)
   {
     size_t nof_elems = p.elems.size();
     for (size_t i = 0; i < nof_elems; i++) elems.add(p.elems[i]->clone());