[erlang-bugs] bogus 'unsafe variable' warning with try-else

[Dmitry Kolesnikov]

Hello,

This is very valid error.  
The variable Bin is defined within code block but it is used out-side of it.

I’ve never heard that any one complained about following error:

   try
   {
      int x = 1;
   } catch (Exception _) {
   }
   x++;

   error: cannot find symbol


Best Regards, 
Dmitry


> On 20 Nov 2014, at 13:49, Mikael Pettersson <mikpelinux@REDACTED> wrote:
> 
> The following, adapted from an example in the online Erlang
> Reference Manual, looks like a bug to me:
> 
>> cat bug.erl
> -module(bug).
> -compile(export_all).
> 
> termize_file(Name) ->
>  {ok,F} = file:open(Name, [read,binary]),
>  try
>    {ok,Bin} = file:read(F, 1024*1024)
>  after
>    file:close(F)
>  end,
>  binary_to_term(Bin).
>> erlc bug.erl
> bug.erl:11: variable 'Bin' unsafe in 'try' (line 6)
> 
> Unless I'm missing something, there is no way to reach the
> binary_to_term/1 call without successfully evaluating the
> {ok,Bin} = ... match expression; therefore the use is not
> unsafe.  If the file:read/2 call or the {ok,Bin} match fails,
> the after clause runs and the entire try expression fails,
> and the binary_to_term/1 is not reached.
> 
> Reproduced with 17.3 and r15b03-1.
> 
> Workaround: match on the value of the try itself:
> "{ok,Bin} = try file:read(...) after ... end".
> 
> /Mikael
> _______________________________________________
> erlang-bugs mailing list
> erlang-bugs@REDACTED
> http://erlang.org/mailman/listinfo/erlang-bugs