Avoid exclamation point operator.

Summary of the new feature

While not technically an alias, ! behaves like an alias to the -not operator. Even “about_Logical_Operators” only mentions it in passing as “Same as -not” Considering that PSScriptAnalyzer has other rules against aliases, and that ! looks different to pretty much all other operator, I think it should also be warned against.

What is the latest version of PSScriptAnalyzer at the point of writing

1.20

[bergmeister]

I think there is no right and wrong since it’s just about readability. PSScriptAnalyzer is not just a code analyser but also a formatter and this is the perfect scenario. I suggest to create a new formatting rule (which can either be run by Invoke-Formatter or by Invoke-ScriptAnalyzer), that lets user highlight or format the code to THEIR preference. I would not turn on the rule by default, neither in PSSA nor in the VS-Code extension but I would add a codeformatting setting for the VS-Code extension. This way, people can be optionally informed of violations of their preferred style and have the ability to have it auto-fixed (both either via command line or in the editor). Would everyone be happy with that?

[JustinGrote]

I am in the -not camp, despite it being a terrible syntax in if statements. I would definitely turn on this rule on my project styles but this is one of those where there isn’t a predominant style unfortunately. Similar to $_ vs $psitem.

As such its a great idea for a rule but should be opt-in I think.