Investigate suspicious location tracking

Some places where code is elaborated the file context is a bit strange, it's probably hiding a bug or at least not explaining itself properly.

`TTImp/ProcessDef.idr`

       processType eopts nest env fc top Public []
          $ MkImpTy fc fc n $ holeyType (map snd args)
          -- Why does the name have the same location as the rest
          -- of the entire expression? That seems incorrect
          $ MkImpTy fc (MkFCVal fc n) $ holeyType (map snd args)

`Idris/Elab/Interface.idr`

Elaborated clauses inheriting a strange location

         let fnclause = PatClause vfc
                                  (INamedApp vfc
                                             -- Another suspicious location
                                             -- why do we take the location of the signature
                                             -- rather than the location of the name?
                                             (IVar sig.location cn.val)
                                             (UN $ Basic "__con")
                                             conapp
                                             )

`Idris/Syntax.idr`

Record field name locations are not tracked

 record RecordField' (nm : Type) where
    constructor MkRecordField
    doc : String
    rig : RigCount
    piInfo : PiInfo (PTerm' nm)
    names : List Name -- Those names should be `WithFC`
    type : PTerm' nm

`TTImp/Elab/Case`

`guessScrType`

the location of tyn is overriden with the location of the original name

                     applyTo defs (IVar (MkFCVal n.fc tyn)) tyty

`updateClause`

The location of cases inherit the locationof the clauses

              lhs' = apply (IVar $ MkFCVal loc' casen) args' in

`TTImp/PartialEval`

in mkRHSargs a lot of names inherit the location of the application node, rather than use their own

181|        = mkRHSargs ty (IApp fc app (IVar $ MkFCVal fc (UN $ Basic a))) as ds

`TTImp/WithClause`

hdLoc is used to give location to names but maybe they shouldn't since the location seems to span a much larger area than the name

`TTImp/BindImplicits`

`bindUsings`

in bindUsings, no location for pi name:

    = IPi (getFC ty) rig p (map NoFC mn) ty (bindUsings us tm)

`piBind` in `piBindNames`

no location used for pi name

205|       = IPi loc erased Implicit (Just (NoFC $ UN $ Basic n)) (Implicit loc False)

idris-lang / Idris2