Fix writing to out-of-bounds arrays writing element 0.

src/V3Ast.cpp

@@ -574,6 +574,14 @@ void AstNode::relinkOneLink(AstNode*& pointpr,  // Ref to pointer that gets set
     pointpr = newp;
 }
 
+void AstNode::addHereThisAsNext (AstNode* newp) {
+    // {old}->this->{next} becomes {old}->new->this->{next}
+    AstNRelinker handle;
+    this->unlinkFrBackWithNext(&handle);
+    newp->addNext(this);
+    handle.relink(newp);
+}
+
 void AstNode::swapWith (AstNode* bp) {
     AstNRelinker aHandle;
     AstNRelinker bHandle;