Method preVisit

src/ast/ast_derive_alias.cpp:99–102

we found source

        virtual bool canVisitMakeBlockBody ( ExprMakeBlock * )  override  { return false; }
    // we found source
        virtual void preVisit ( ExprVar * expr ) override {
            Visitor::preVisit(expr);
            if ( !disabled ) sources.insert(expr->variable);
        }
    // in [] only value can alias
        virtual void preVisit ( ExprAt * expr ) override {
            Visitor::preVisit(expr);