Unintuitive wellformedness warnings for fact usage

[kevinmorio]

When checking the fact usage (capitalization, arity, multiplicity) facts in the LHS and RHS of rules as well as action facts are included leading to unintuitive wellformedness warnings.

For example, the theory

theory FactUsage
begin

rule Init:
  [] --[ Init() ]-> [ !Init() ]

end

produces the warning:

/*
WARNING: the following wellformedness checks failed!

Fact usage
==========

Possible reasons: 
1. Fact names are case-sensitive, different capitalizations are considered as different facts, i.e., Fact() is different from FAct(). Check the capitalization of your fact names.
2. Same fact is used with different arities, i.e., Fact('A','B') is different from Fact('A'). Check the arguments of your facts.
 
  
Fact `init':

  1. Rule `Init', capitalization  "Init", 0, Persistent
       !Init( )
  
  2. Rule `Init', capitalization  "Init", 0, Linear
       Init( )
*/

Intuitively, action facts and facts on the LHS and RHS should be compared separately as they are independent from each other.
Moreover, reason 1 above can be ruled out as the capitalization is the same.

[jdreier]

I think there are two points here:

1. The warning messages could be more precise: at least, a add remark that this check also checks for persistence, or even, for each issue, give the exact warning, rather then the current generic message ("possible reasons") followed by a list of all issues
2. Should we treat action facts differently, or not?

[rsasse]

On 2: semantically they are of course different, however I have seen many novice users confuse themselves when using the same fact name for actions and state facts. This warning does not help them though, so I am undecided on changing.

Being more precise in the actual warning given, when capitalization is identical, would be good. It will still be a problem when there are three instances, two are capitalized the same, but third is not, then it must be shown and has the same downside about not being relevant for all.