diff --git a/glslang/MachineIndependent/iomapper.h b/glslang/MachineIndependent/iomapper.h
index e91a1509..a6f2480c 100644
--- a/glslang/MachineIndependent/iomapper.h
+++ b/glslang/MachineIndependent/iomapper.h
@@ -244,7 +244,7 @@ struct TVarLivePair : std::pair<const TString, TVarEntryInfo> {
         second = _Right.second;
         return (*this);
     }
-    TVarLivePair(const TVarLivePair& src) { *this = src; }
+    TVarLivePair(const TVarLivePair& src) : pair(src) { }
 };
 typedef std::vector<TVarLivePair> TVarLiveVector;