C2::Decl* C2Sema::ActOnAliasType(const char* name, SourceLocation loc, Expr* type, bool is_public) {
    assert(name);
    assert(type);
#ifdef SEMA_DEBUG
    std::cerr << COL_SEMA"SEMA: alias type def " << name << " at ";
    loc.dump(SourceMgr);
    std::cerr << ANSI_NORMAL"\n";
#endif
    if (ast.isInterface()) {
        if (is_public) Diag(loc, diag::err_public_in_interface);
        is_public = true;
    }
    TypeExpr* typeExpr = cast<TypeExpr>(type);
    if (typeExpr->hasLocalQualifier()) {
        Diag(loc, diag::err_invalid_local_typedef);
    }
    AliasTypeDecl* T = new AliasTypeDecl(name, loc, typeExpr->getType(), is_public);
    QualType A = typeContext.getAliasType(T, typeExpr->getType());
    T->setType(A);
    ast.addType(T);
    addSymbol(T);
    delete typeExpr;
    return T;
}

 static inline bool isConst(const TypeExpr& te) {
   return te.resolved()
          ? te.resolved()->isConst()
          : te.spec()->isConst();
 }

 static inline bool isByRef(const TypeExpr& te) {
   return te.resolved()
          ? te.resolved()->isReference()
          : te.spec()->isByRef();
 }