Remove $ as a valid char in class and method names

[BraisGabin]

This issue was spotted in #2656 (but it's not completely related with that issue).

Extracted from the issue:

I just realised. Why do we allow classes with $ in the name? It has little sense. The $ is usually used by the annotation processors to create new classes. And they use that symbol to get a name that is not going to conflict with the user class names. Our tests didn't check the use of $ neighter. And you can't use te symbol $ if you don't use the char `. I think that it's safe to remove it.

I can't even write tests for this change because I can't create a name of a class with $ if I'm not using . And the use of in class names is exactly what is being talked in #2656. Right now we don't allow it.

[codecov]

Codecov Report

Merging #2662 into master will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #2662      +/-   ##
============================================
- Coverage     80.00%   79.98%   -0.02%     
- Complexity     2292     2303      +11     
============================================
  Files           379      380       +1     
  Lines          6761     6770       +9     
  Branches       1222     1224       +2     
============================================
+ Hits           5409     5415       +6     
  Misses          740      740              
- Partials        612      615       +3     

Impacted Files	Coverage Δ	Complexity Δ
...tlab/arturbosch/detekt/rules/naming/ClassNaming.kt	100.00% <100.00%> (ø)	4.00 <0.00> (ø)
...b/arturbosch/detekt/rules/naming/FunctionNaming.kt	94.73% <100.00%> (ø)	9.00 <0.00> (ø)
...ules/style/optional/MandatoryBracesIfStatements.kt	64.28% <0.00%> (-7.94%)	14.00% <0.00%> (ø%)
...bosch/detekt/rules/providers/StyleGuideProvider.kt	100.00% <0.00%> (ø)	2.00% <0.00%> (ø%)
...etekt/rules/style/optional/MandatoryBracesLoops.kt	75.00% <0.00%> (ø)	11.00% <0.00%> (?%)

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[schalkms]

Shouldn’t this be adapted for functions an other elements as well?

[BraisGabin]

I didn't think of that. Yeah, I'm going to check if we have the same bug in the other ones

[BraisGabin]

Updated.

[schalkms]

Can variables and parameters also have `` in the name?

[BraisGabin]

Can variables and parameters also have `` in the name?

I think that I'm missing something. This PR is not related with the use of . It just removes $` as a valid char in the function and method names.

In the parameters and variables we wasn't allowing that char so there's nothing to change there.

[schalkms]

Thanks for the clarification! @BraisGabin