[erlang-bugs] sys_core_fold forgets about aliases when marking bit string variables for context reusing

Anthony Ramine <>
Sun Dec 1 13:21:05 CET 2013


A PR was created by Henrik, it may as well be announced here…:

	https://github.com/erlang/otp/pull/150

-- 
Anthony Ramine

Le 16 nov. 2013 à 13:58, Anthony Ramine <> a écrit :

> Finally I may have found one.
> 
> Tell me where I should write tests for that and I will add them.
> 
> 	git fetch https://github.com/nox/otp.git core-clause-subst
> 
> 	https://github.com/nox/otp/compare/erlang:maint...core-clause-subst
> 	https://github.com/nox/otp/compare/erlang:maint...core-clause-subst.patch
> 
> Regards,
> 
> -- 
> Anthony Ramine
> 
> Le 16 nov. 2013 à 13:27, Anthony Ramine <> a écrit :
> 
>> Hello,
>> 
>> I have trying to fix a bug for a while without success so I post it here.
>> 
>> t(Bin1) ->
>>   case Bin1 of
>>       <<>> -> ok;
>>       Bin2 ->
>>           case Bin1 of
>>               <<0>> -> ok;
>>               _ -> Bin2
>>           end
>>   end.
>> 
>> In the following function, sys_core_fold fails to see that Bin2 is an alias of Bin1 and does not emit a bs_context_to_binary, making beam_validator crash quite violently:
>> 
>> t: function t/1+17:
>> Internal consistency check failed - please report this bug.
>> Instruction: return
>> Error:       {match_context,{x,0}}:
>> 
>> Regards,
>> 
>> -- 
>> Anthony Ramine
>> 
> 



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