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

Björn-Egil Dahlberg <>
Thu Nov 27 21:13:21 CET 2014


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
> ============================================================
>
> _______________________________________________
> erlang-questions mailing list
> 
> http://erlang.org/mailman/listinfo/erlang-questions
>
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