Do not patch Tuple1/Tuple2 with specialized methods

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1726,8 +1726,9 @@ class Definitions {
     isFunctionType(tp) || isRefinedFunctionType(tp)
 
   private def withSpecMethods(cls: ClassSymbol, bases: List[Name], paramTypes: Set[TypeRef]) =
-    for base <- bases; tp <- paramTypes do
-      cls.enter(newSymbol(cls, base.specializedName(List(tp)), Method, ExprType(tp)))
+    if !ctx.settings.Yscala2Stdlib.value then
+      for base <- bases; tp <- paramTypes do
+        cls.enter(newSymbol(cls, base.specializedName(List(tp)), Method, ExprType(tp)))
     cls
 
   @tu lazy val Tuple1: ClassSymbol = withSpecMethods(requiredClass("scala.Tuple1"), List(nme._1), Tuple1SpecializedParamTypes)
@@ -1768,6 +1769,7 @@ class Definitions {
       case List(x, y) => Tuple2SpecializedParamClasses().contains(x.classSymbol) && Tuple2SpecializedParamClasses().contains(y.classSymbol)
       case _          => false
     && base.owner.denot.info.member(base.name.specializedName(args)).exists // when dotc compiles the stdlib there are no specialised classes
+    && !ctx.settings.Yscala2Stdlib.value // We do not add the specilized TupleN methods/classes when compiling the stdlib
 
   def isSpecializableFunction(cls: ClassSymbol, paramTypes: List[Type], retType: Type)(using Context): Boolean =
     paramTypes.length <= 2

compiler/src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -574,11 +574,7 @@ object TreeChecker {
 
       val symbolsNotDefined = (decls -- defined - constr.symbol).filterNot(isAllowed)
 
-      def isStdlibBootstrappedIssue =
-        // FIXME: specialized members of TupleN are failing. These should not exist.
-        ctx.settings.Yscala2Stdlib.value && defn.isTupleClass(cls)
-
-      assert(symbolsNotDefined.isEmpty || isStdlibBootstrappedIssue,
+      assert(symbolsNotDefined.isEmpty,
         i" $cls tree does not define members: ${symbolsNotDefined.toList}%, %\n" +
         i"expected: ${decls.toList}%, %\n" +
         i"defined: ${defined}%, %")