Ignore constants that have not been initialized.

src/OpenGL/compiler/parseConst.cpp

@@ -148,6 +148,13 @@ bool TConstTraverser::visitSelection(Visit visit, TIntermSelection* node)
 
 void TConstTraverser::visitConstantUnion(TIntermConstantUnion* node)
 {
+    if (!node->getUnionArrayPointer())
+    {
+        // The constant was not initialized, this should already have been logged
+        assert(infoSink.info.size() != 0);
+        return;
+    }
+
     ConstantUnion* leftUnionArray = unionArray;
     int instanceSize = type.getObjectSize();
     TBasicType basicType = type.getBasicType();