[Rd] 'unique' error message is printed despite silent=TRUE (PR#13547)

[Wacek Kusnierczyk]

macrakis at alum.mit.edu wrote:
> In 2.8.0/Windows Vista:
>
> When 'unique' gives a type error message, it prints out even if errors
> are being caught:
>
>   
>> try(unique(quote(hello)),silent=TRUE)
>>     
> hello
>
> This comes from the .Internal unique routine:
>
>   
>> try(.Internal(unique(quote(hello),NULL,NULL)),silent=TRUE)
>>     
> hello
>
> I guess it is using the internal equivalent of print rather than the
> internal equivalent of stop.
>
>   
line 454+ in src/main/unique.c:

    if (!isVector(x)) {
    PrintValue(x);
    error(_("%s() applies only to vectors"),
          (PRIMVAL(op) == 0 ? "duplicated" : "unique"));
    }

in your example, quote() produces a non-vector, hence the output before
the error message.

vQ