fix distinct operator

[polgreen]

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Adds support for distinct operator in smt2 parser (which is syntactic sugar for a pairwise "not equal" predicate). Previously operator was parsed but later ignored

[martin-cs]

Sorry but I don't think this is the correct semantics. I think that distinct is pair-wise inequality.

[martin-cs]

I don't think this is the semantics of SMT-LIB distinct. It is described here ( http://smtlib.cs.uiowa.edu/theories-Core.shtml ) as:

(par (A) (distinct A A Bool :pairwise))

And :pairwise is described on Page 34 of http://smtlib.cs.uiowa.edu/papers/smt-lib-reference-v2.6-r2017-07-18.pdf as:

[pairwise annotation] (f   t1···tn) is syntactic sugar (recursively) for (and (f   t1 t2) ··· (f   t1 tn) (f   t2···tn)).

[martin-cs]

Much better -- thank you!

[martin-cs]

You could start at j = i + 1 and skip this check if you wanted.

[codecov]

Codecov Report

Merging #5827 (9778868) into develop (23c11e8) will increase coverage by 3.76%.
The diff coverage is 95.28%.

@@             Coverage Diff             @@
##           develop    #5827      +/-   ##
===========================================
+ Coverage    69.08%   72.85%   +3.76%     
===========================================
  Files         1242     1423     +181     
  Lines       100842   154072   +53230     
===========================================
+ Hits         69667   112244   +42577     
- Misses       31175    41828   +10653     

Flag	Coverage Δ
regression	?
unit	?

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Impacted Files	Coverage Δ
...ses/variable-sensitivity/interval_abstract_value.h	100.00% <ø> (ø)
...s/variable-sensitivity/value_set_abstract_object.h	100.00% <ø> (ø)
...-sensitivity/variable_sensitivity_object_factory.h	100.00% <ø> (ø)
...riable-sensitivity/full_struct_abstract_object.cpp	81.81% <33.33%> (-0.09%)	⬇️
.../analyses/variable-sensitivity/abstract_object.cpp	69.15% <50.00%> (-4.80%)	⬇️
...yses/variable-sensitivity/abstract_environment.cpp	87.42% <87.50%> (+2.02%)	⬆️
...s/variable-sensitivity/interval_abstract_value.cpp	78.77% <94.44%> (-0.88%)	⬇️
...variable-sensitivity/value_set_abstract_object.cpp	87.01% <97.14%> (+15.58%)	⬆️
...alyses/variable-sensitivity/abstract_environment.h	100.00% <100.00%> (ø)
...s/variable-sensitivity/constant_abstract_value.cpp	94.31% <100.00%> (+2.31%)	⬆️
... and 1381 more

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