[erlang-questions] Why does Dialyzer crash on this map?

Ali Sabil <>
Wed Mar 18 12:01:36 CET 2015


I tried to create a minimal testcase but I unfortunately haven't been able
to. I was running dialyzer on a quite large code base and now even the
unpatched dialyzer works without any issue after I fixed all the issues
reported by dialyzer.

On Tue, Mar 17, 2015 at 5:38 PM, Björn-Egil Dahlberg <>
wrote:

>  On 2015-03-13 11:20, Ali Sabil wrote:
>
> Has this been solved for 17.4? I am getting the same crash on a quite
> large code base using 17.4.1
>
>
> Do you have a minimized testcase that fails on maint? I couldn't reproduce
> it with dt or dt2.
>
> I'll add the missing map type in find_terminals.
>
> // Björn-Egil
>
>
>
>  Thanks,
> Ali
>
> On Thu, Nov 27, 2014 at 10:05 PM, Ivan Uemlianin <> wrote:
>
>>  Dear Björn-Egil
>>
>>  Thanks very much for your work and for reporting back. It looks like
>> good news (for me and for 18 at least).
>>
>>  Best wishes
>>
>>  Ivan
>>
>> --
>> festina lente
>>
>>
>> On 27 Nov 2014, at 20:52, Björn-Egil Dahlberg <
>> > wrote:
>>
>>   Looks like the regression was introduced in
>> 'hb/dialyzer/fix_recognition_of_records/OTP-11935'
>> (805f9c89fc01220bc1bb0f27e1b68fd4eca688ba) included from OTP 17.1
>>
>>  This becomes a none-issue in the master branch (for 18) since variables
>> are allowed as keys there but it needs to be solved for the 17 track.
>>
>>
>> 2014-11-27 21:13 GMT+01:00 Björn-Egil Dahlberg <
>> >:
>>
>>> I managed to reproduce your errors on dt.erl and dt2.erl using
>>> OTP-17.3.3 tag.
>>>
>>>  Seems like I've missed something in dataflow .. looks like a clause
>>> missing for the map type.
>>> I'm not well versed in dialyzer. Hopefully I can do a fix for it for
>>> 17.4.
>>>
>>>  There are a bit more stuff going on here too. When dialyzer uses the
>>> erlang compiler to compile to core
>>> it does not coalesce things to literals but keeps them abstract instead
>>> ..
>>> Compound keys such as [1,2,3] and {4,5,6} will thus become non-literals
>>> (variables) and such keys are not allowed in maps.
>>>
>>>  I need to ponder that a bit before I try to solve it.
>>>
>>>  // Björn-Egil
>>>
>>> 2014-11-27 13:20 GMT+01:00 Ivan Uemlianin <>:
>>>
>>>> Dear Dave
>>>>
>>>> Thanks for your help.  Here are some more details:
>>>>
>>>>
>>>> *** OS: FreeBSD 10.0-RELEASE
>>>>
>>>> $ uname -a
>>>> FreeBSD simba 10.0-RELEASE FreeBSD 10.0-RELEASE #0 r260789: Thu Jan 16
>>>> 22:34:59 UTC 2014 :/usr/obj/usr/src/sys/GENERIC
>>>> amd64
>>>>
>>>> Upgrading to 10.1 is on my todo list.
>>>>
>>>>
>>>> *** Erlang version now 17.3_3,3
>>>>
>>>> $ pkg info erlang
>>>> erlang-17.3_1,3
>>>> ...
>>>> $ sudo pkg upgrade
>>>> ...
>>>>
>>>> $ pkg info erlang
>>>> erlang-17.3_3,3
>>>> ...
>>>>
>>>>
>>>> *** Errors persist
>>>>
>>>> Upgrading erlang has not changed behaviour.
>>>>
>>>> A couple more observations:
>>>>
>>>> 1. Running dialyzer on the module dt below gets the error as noted
>>>> previously.  However, if I uncomment the '%% ok' line, dialyzer will
>>>> process the module with no problems.
>>>>
>>>>     -module(dt).
>>>>     -export([get_map/0]).
>>>>
>>>>     -spec get_map() -> map().
>>>>     get_map() ->
>>>>         #{labels => [one, two],
>>>>           number => 27,
>>>>  %%          [1,2,3] => wer,        %% ok
>>>>           kvok => #{
>>>>                 a => qwe,
>>>>                 2 => asd,
>>>>                 [1,2,3] => wer,  %% bad
>>>>                 {4,5,6} => sdf,  %% bad
>>>>                 "abc" => zxc
>>>>            }
>>>>          }.
>>>>
>>>>      $ dialyzer dt.erl
>>>>       Checking whether the PLT /home/ivan/.dialyzer_plt is
>>>> up-to-date... yes
>>>>       Proceeding with analysis...
>>>>     =ERROR REPORT==== 27-Nov-2014::12:17:02 ===
>>>>     Error in process <0.45.0> with exit value:
>>>> {{case_clause,map},[{dialyzer_dataflow,find_terminals,1,[{file,"dialyzer_dataflow.erl"},{line,3451}]},{dialyzer_dataflow,find_terminals_list,3,[{file,"dialyzer_dataflow.erl"},{line,3504}]},{dialyzer_dataflow,classify_returns...
>>>>
>>>>
>>>>
>>>>      dialyzer: Analysis failed with error:
>>>>      {{case_clause,map},
>>>>      [{dialyzer_dataflow,find_terminals,1,
>>>> [{file,"dialyzer_dataflow.erl"},{line,3451}]},
>>>>       {dialyzer_dataflow,find_terminals_list,3,
>>>> [{file,"dialyzer_dataflow.erl"},{line,3504}]},
>>>>       {dialyzer_dataflow,classify_returns,1,
>>>> [{file,"dialyzer_dataflow.erl"},{line,3443}]},
>>>>       {dialyzer_dataflow,'-state__get_warnings/2-fun-0-',7,
>>>> [{file,"dialyzer_dataflow.erl"},{line,2908}]},
>>>>       {lists,foldl,3,[{file,"lists.erl"},{line,1261}]},
>>>>       {dialyzer_dataflow,state__get_warnings,2,
>>>> [{file,"dialyzer_dataflow.erl"},{line,2934}]},
>>>>       {dialyzer_dataflow,get_warnings,5,
>>>> [{file,"dialyzer_dataflow.erl"},{line,142}]},
>>>>       {dialyzer_succ_typings,collect_warnings,2,
>>>> [{file,"dialyzer_succ_typings.erl"},{line,182}]}]}
>>>>      Last messages in the log cache:
>>>>       Reading files and computing callgraph... done in 0.07 secs
>>>>       Removing edges... done in 0.00 secs
>>>>
>>>>
>>>>  2. Running dialyzer on the module dt2 below raises the warning
>>>> following.  Uncommenting the '%% ok' line has no effect.
>>>>
>>>>     -module(dt2).
>>>>     -export([get_map/0]).
>>>>
>>>>     -spec get_map() -> map().
>>>>     get_map() ->
>>>>          X = #{labels => [one, two],
>>>>           number => 27,
>>>> %%          [1,2,3] => wer,        %% ok
>>>>           kvok => #{
>>>>                 a => qwe,
>>>>                 2 => asd,
>>>>                 [1,2,3] => wer,  %% bad
>>>>                 {4,5,6} => sdf,  %% bad
>>>>                 "abc" => zxc
>>>>            }
>>>>           },
>>>>         X.
>>>>
>>>>     $ dialyzer dt2.erl
>>>>       Checking whether the PLT /home/ivan/.dialyzer_plt is
>>>> up-to-date... yes
>>>>       Proceeding with analysis...
>>>>     dt2.erl:5: Function get_map/0 has no local return
>>>>      done in 0m0.41s
>>>>     done (warnings were emitted)
>>>>
>>>> Best wishes
>>>>
>>>> Ivan
>>>>
>>>>
>>>>
>>>>
>>>> On 11/25/14 20:37, Dave Cottlehuber wrote:
>>>>
>>>>> Sorry about that last email …
>>>>>
>>>>> EWORKSFORME.
>>>>>
>>>>> FreeBSD 10.1 amd64, erlang-17.3_2,3 from pkg.
>>>>>
>>>>> What FreeBSD & erlang are you using?
>>>>>
>>>>> dch   /tmp ❯❯❯   dialyzer --build_plt --apps erts kernel stdlib
>>>>>    Creating PLT /home/dch/.dialyzer_plt ...
>>>>> Unknown functions:
>>>>>    compile:file/2
>>>>>    compile:forms/2
>>>>>    compile:noenv_forms/2
>>>>>    compile:output_generated/1
>>>>>    crypto:block_decrypt/4
>>>>>    crypto:start/0
>>>>> Unknown types:
>>>>>    compile:option/0
>>>>>   done in 1m8.53s
>>>>> done (passed successfully)
>>>>>
>>>>> dch   /tmp ❯❯❯dialyzer ltu.erl
>>>>>    Checking whether the PLT /home/dch/.dialyzer_plt is up-to-date...
>>>>> yes
>>>>>    Proceeding with analysis... done in 0m0.41s
>>>>> done (passed successfully)
>>>>>
>>>>> dch   /tmp ❯❯❯erl
>>>>> Erlang/OTP 17 [erts-6.2] [source] [64-bit] [smp:8:8]
>>>>> [async-threads:64] [kernel-poll:true]
>>>>>
>>>>> Eshell V6.2  (abort with ^G)
>>>>> 1>
>>>>>
>>>>> A+, Dave
>>>>> — sent from my Couch
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> erlang-questions mailing list
>>>>> 
>>>>> http://erlang.org/mailman/listinfo/erlang-questions
>>>>>
>>>>
>>>>  --
>>>> ============================================================
>>>> Ivan A. Uemlianin PhD
>>>> Llaisdy
>>>> Speech Technology Research and Development
>>>>
>>>>                      
>>>>                         @llaisdy
>>>>                          llaisdy.wordpress.com
>>>>               github.com/llaisdy
>>>>                      www.linkedin.com/in/ivanuemlianin
>>>>
>>>>                         festina lente
>>>> ============================================================
>>>>
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>>>> 
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>>>
>>>
>>
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