Change Yspecialize behaviour

Changes type from `StringSetting` to `IntSetting`.
Value x passed to the setting is the maximum number of parameters to
specialize. Any method with type parameters will see the x first (or
all if there are not enough) of them specialized.

Conflicts:
	src/dotty/tools/dotc/config/ScalaSettings.scala

Author: AlexSikia

src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -152,7 +152,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val YprintSyms = BooleanSetting("-Yprint-syms", "when printing trees print info in symbols instead of corresponding info in trees.")
   val YtestPickler = BooleanSetting("-Ytest-pickler", "self-test for pickling functionality; should be used with -Ystop-after:pickler")
   val YcheckReentrant = BooleanSetting("-Ycheck-reentrant", "check that compiled program does not contain vars that can be accessed from a global root.")
-  val Yspecialize = StringSetting("-Yspecialize","","Specialize all methods.", "")
+  val Yspecialize = IntSetting("-Yspecialize","Specialize methods with maximum this amount of polymorphic types.", 0, 0 to 10)
 
   def stop = YstopAfter
 

src/dotty/tools/dotc/transform/TypeSpecializer.scala

@@ -77,18 +77,16 @@ class TypeSpecializer extends MiniPhaseTransform  with InfoTransformer {
       poly.paramNames.zipWithIndex.map{case(name, i) => (i, requested.getOrElse(i, Nil))}
     }
     else {
-      if (ctx.settings.Yspecialize.value == "all") {
+      if (ctx.settings.Yspecialize.value > 0) {
         val filteredPrims = primitiveTypes.filter(tpe => poly.paramBounds.forall(_.contains(tpe)))
-        List.range(0, poly.paramNames.length).map(i => (i, filteredPrims))
+        List.range(0, Math.min(poly.paramNames.length, ctx.settings.Yspecialize.value)).map(i => (i, filteredPrims))
       }
       else Nil
     }
   }
 
   def requestedSpecialization(decl: Symbol)(implicit ctx: Context): Boolean =
-    specializationRequests.contains(decl) ||
-      (ctx.settings.Yspecialize.value != "" && decl.name.contains(ctx.settings.Yspecialize.value)) ||
-      ctx.settings.Yspecialize.value == "all"
+    ctx.settings.Yspecialize.value != 0 || specializationRequests.contains(decl)
 
   def registerSpecializationRequest(method: Symbols.Symbol)(index: Int, arguments: List[Type])(implicit ctx: Context) = {
     if (ctx.phaseId > this.treeTransformPhase.id)