Stress test for add-class-deps

This commit makes all explicitly declared vals tracked. It causes many test failures, which
makes it unlikely that we will be able to do this in the end. But it's an excellent basis
for stress testing the implementation of dependent classes.

The idea is to

 - look at the test failures in this test
 - convert failing tests into tests witih explicit tracked annotations
 - if the test still fails (it probably will), try to fix the root cause
   or determine that the pattern should not be supported.

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -53,15 +53,17 @@ object Parsers {
   enum ParamOwner:
     case Class           // class or trait or enum
     case CaseClass       // case class or enum case
+    case ImplicitClass   // implicit class
     case Type            // type alias or abstract type
     case TypeParam       // type parameter
     case Def             // method
     case Given           // given definition
     case ExtensionPrefix // extension clause, up to and including extension parameter
     case ExtensionFollow // extension clause, following extension parameter
 
-    def isClass = // owner is a class
-      this == Class || this == CaseClass || this == Given
+    def isClass = this match // owner is a class
+      case Class | CaseClass | ImplicitClass | Given => true
+      case _ => false
     def takesOnlyUsingClauses = // only using clauses allowed for this owner
       this == Given || this == ExtensionFollow
     def acceptsVariance =
@@ -3361,6 +3363,8 @@ object Parsers {
           mods = addFlag(modifiers(start = mods), ParamAccessor)
           mods =
             if in.token == VAL then
+              if !mods.is(Private) && paramOwner != ParamOwner.ImplicitClass then
+                mods |= Tracked
               in.nextToken()
               mods
             else if in.token == VAR then
@@ -3898,7 +3902,10 @@ object Parsers {
     }
 
     def classDefRest(start: Offset, mods: Modifiers, name: TypeName): TypeDef =
-      val constr = classConstr(if mods.is(Case) then ParamOwner.CaseClass else ParamOwner.Class)
+      val constr = classConstr(
+        if mods.is(Case) then ParamOwner.CaseClass
+        else if mods.is(Implicit) then ParamOwner.ImplicitClass
+        else ParamOwner.Class)
       val templ = templateOpt(constr)
       finalizeDef(TypeDef(name, templ), mods, start)