Add the range statement to the constant resolver

[ghaith]

Fixes #591

[codecov-commenter]

Codecov Report

Base: 93.66% // Head: 93.67% // Increases project coverage by +0.01% 🎉

Coverage data is based on head (3664b51) compared to base (630ff16).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #612      +/-   ##
==========================================
+ Coverage   93.66%   93.67%   +0.01%     
==========================================
  Files          44       44              
  Lines       16804    16815      +11     
==========================================
+ Hits        15740    15752      +12     
+ Misses       1064     1063       -1     

Impacted Files	Coverage Δ
src/resolver/const_evaluator.rs	90.35% <100.00%> (+0.25%)	⬆️
src/validation.rs	96.38% <0.00%> (+0.32%)	⬆️

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[riederm]

I dont believe that ranges will work that easily
we would need to unroll it like:

case (3..10) --> needs to become case 3,4,5,6,7,8,9,10 or we need to rewrite the switch-statement to if-elseif-elseif-...-else

[riederm]

does this look correct? this switch does nothing but else, right?

[ghaith]

I also thought this was strange, I can add a correctness test with the constants, but we do have some that take care of the range

[ghaith]

I dont believe that ranges will work that easily we would need to unroll it like:

case (3..10) --> needs to become case 3,4,5,6,7,8,9,10 or we need to rewrite the switch-statement to if-elseif-elseif-...-else

This commit is only making sure the constants in the ranges are resolved.
The unroll functionality is already implemented, we have correctness tests for them as well (https://github.com/PLC-lang/rusty/blob/master/tests/correctness/control_flow.rs -> case_statement)

[riederm]

yep I didnt look into the else thoroughly