Always run the compiler with a bootstrapped dotty-library

compiler/src/dotty/tools/dotc/Bench.scala

@@ -4,6 +4,8 @@ package dotc
 import core.Contexts.Context
 import reporting.Reporter
 
+import scala.annotation.internal.sharable
+
 /** A main class for running compiler benchmarks. Can instantiate a given
  *  number of compilers and run each (sequentially) a given number of times
  *  on the same sources.

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -13,6 +13,8 @@ import collection.mutable.ListBuffer
 import reporting.diagnostic.messages._
 import reporting.trace
 
+import scala.annotation.internal.sharable
+
 object desugar {
   import untpd._
   import DesugarEnums._

compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala

@@ -10,6 +10,8 @@ import collection.mutable.ListBuffer
 import util.Property
 import typer.ErrorReporting._
 
+import scala.annotation.internal.sharable
+
 /** Helper methods to desugar enums */
 object DesugarEnums {
   import untpd._

compiler/src/dotty/tools/dotc/ast/Trees.scala

@@ -14,6 +14,7 @@ import parsing.Tokens.Token
 import printing.Printer
 import util.{Stats, Attachment, Property, DotClass}
 import config.Config
+import annotation.internal.sharable
 import annotation.unchecked.uncheckedVariance
 import language.implicitConversions
 

compiler/src/dotty/tools/dotc/ast/untpd.scala

@@ -11,6 +11,8 @@ import language.higherKinds
 import collection.mutable.ListBuffer
 import reflect.ClassTag
 
+import scala.annotation.internal.sharable
+
 object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
 
   // ----- Tree cases that exist in untyped form only ------------------

compiler/src/dotty/tools/dotc/config/CommandLineParser.scala

@@ -2,7 +2,7 @@ package dotty.tools.dotc
 package config
 
 import scala.annotation.tailrec
-import dotty.tools.sharable
+import scala.annotation.internal.sharable
 
 /** A simple (overly so) command line parser.
  *  !!! This needs a thorough test suite to make sure quoting is

compiler/src/dotty/tools/dotc/config/Properties.scala

@@ -2,6 +2,8 @@ package dotty.tools
 package dotc
 package config
 
+import scala.annotation.internal.sharable
+
 import java.io.{ IOException, PrintWriter }
 import java.util.jar.Attributes.{ Name => AttributeName }
 

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

@@ -94,6 +94,8 @@ class ScalaSettings extends Settings.SettingGroup {
   val YlogClasspath = BooleanSetting("-Ylog-classpath", "Output information about what classpath is being applied.")
   val YdisableFlatCpCaching  = BooleanSetting("-YdisableFlatCpCaching", "Do not cache flat classpath representation of classpath elements from jars across compiler instances.")
 
+  val Yscala2Unpickler = StringSetting("-Yscala2-unpickler", "", "Control where we may get Scala 2 symbols from. This is either \"always\", \"never\", or a classpath.", "always")
+
   val YnoImports = BooleanSetting("-Yno-imports", "Compile without importing scala.*, java.lang.*, or Predef.")
   val YnoInline = BooleanSetting("-Yno-inline", "Suppress inlining.")
   val YnoGenericSig = BooleanSetting("-Yno-generic-signatures", "Suppress generation of generic signatures for Java.")

compiler/src/dotty/tools/dotc/config/ScalaVersion.scala

@@ -3,6 +3,7 @@
 package dotty.tools
 package dotc.config
 
+import scala.annotation.internal.sharable
 import scala.util.{Try, Success, Failure}
 
 /**

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

@@ -29,6 +29,8 @@ import collection.immutable.BitSet
 import printing._
 import config.{JavaPlatform, Platform, ScalaSettings, Settings}
 
+import scala.annotation.internal.sharable
+
 import language.implicitConversions
 import DenotTransformers.DenotTransformer
 import dotty.tools.dotc.profile.Profiler

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

@@ -11,6 +11,8 @@ import Decorators._
 import Contexts.Context
 import collection.mutable
 
+import scala.annotation.internal.sharable
+
 /** Defines possible kinds of NameInfo of a derived name */
 object NameKinds {
 

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

@@ -16,6 +16,8 @@ import util.{DotClass}
 import config.Config
 import java.util.HashMap
 
+import scala.annotation.internal.sharable
+
 object Names {
   import NameKinds._
 

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

@@ -24,6 +24,8 @@ import reporting.diagnostic.Message
 import reporting.diagnostic.messages.BadSymbolicReference
 import reporting.trace
 
+import scala.annotation.internal.sharable
+
 trait SymDenotations { this: Context =>
   import SymDenotations._
 

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

@@ -31,6 +31,7 @@ import io.AbstractFile
 import language.implicitConversions
 import util.{NoSource, DotClass, Property}
 import scala.collection.JavaConverters._
+import scala.annotation.internal.sharable
 import config.Printers.typr
 
 /** Creation methods for symbols */

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

@@ -19,6 +19,8 @@ import ast.tpd._
 import reporting.trace
 import reporting.diagnostic.Message
 
+import scala.annotation.internal.sharable
+
 trait TypeOps { this: Context => // TODO: Make standalone object.
 
   /** The type `tp` as seen from prefix `pre` and owner `cls`. See the spec

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

@@ -14,6 +14,8 @@ import collection.mutable
 import java.lang.ref.WeakReference
 import Decorators._
 
+import scala.annotation.internal.sharable
+
 object TyperState {
   @sharable private var nextId: Int = 0
 }

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

@@ -36,6 +36,8 @@ import scala.util.hashing.{ MurmurHash3 => hashing }
 import config.Printers.{core, typr}
 import java.lang.ref.WeakReference
 
+import scala.annotation.internal.sharable
+
 object Types {
 
   @sharable private[this] var nextId = 0

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -755,6 +755,20 @@ class ClassfileParser(
       }
 
       def unpickleScala(bytes: Array[Byte]): Some[Embedded] = {
+        val allowed = ctx.settings.Yscala2Unpickler.value
+
+        def failUnless(cond: Boolean) =
+          assert(cond,
+            s"Unpickling ${classRoot.symbol.showLocated} from ${classRoot.symbol.associatedFile} is not allowed with -Yscala2-unpickler $allowed")
+
+        if (allowed != "always") {
+          failUnless(allowed != "never")
+          val allowedList = allowed.split(":").toList
+          val file = classRoot.symbol.associatedFile
+          // Using `.toString.contains` isn't great, but it's good enough for a debug flag.
+          failUnless(file == null || allowedList.exists(path => file.toString.contains(path)))
+        }
+
         val unpickler = new unpickleScala2.Scala2Unpickler(bytes, classRoot, moduleRoot)(ctx)
         unpickler.run()(ctx.addMode(Scala2UnpicklingMode))
         Some(unpickler)

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -25,6 +25,8 @@ import scala.quoted
 import scala.quoted.Types.TreeType
 import scala.quoted.Exprs.TastyTreeExpr
 
+import scala.annotation.internal.sharable
+
 /** Unpickler for typed trees
  *  @param reader              the reader from which to unpickle
  *  @param posUnpicklerOpt     the unpickler for positions, if it exists

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

@@ -2,6 +2,7 @@ package dotty.tools
 package dotc
 package parsing
 
+import scala.annotation.internal.sharable
 import scala.collection.mutable.ListBuffer
 import scala.collection.immutable.BitSet
 import util.{ SourceFile, SourcePosition }

compiler/src/dotty/tools/dotc/printing/Printer.scala

@@ -9,6 +9,8 @@ import Types.Type, Symbols.Symbol, Contexts.Context, Scopes.Scope, Constants.Con
 import typer.Implicits.SearchResult
 import typer.ImportInfo
 
+import scala.annotation.internal.sharable
+
 /** The base class of all printers
  */
 abstract class Printer {

compiler/src/dotty/tools/dotc/reporting/Reporter.scala

@@ -2,6 +2,8 @@ package dotty.tools
 package dotc
 package reporting
 
+import scala.annotation.internal.sharable
+
 import core.Contexts._
 import util.{SourcePosition, NoSourcePosition}
 import core.Decorators.PhaseListDecorator

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

@@ -50,9 +50,9 @@ class CheckReentrant extends MiniPhase {
   private[this] var indent: Int = 0
 
   private val sharableAnnot = new CtxLazy(implicit ctx =>
-    ctx.requiredClass("dotty.tools.sharable"))
+    ctx.requiredClass("scala.annotation.internal.sharable"))
   private val unsharedAnnot = new CtxLazy(implicit ctx =>
-    ctx.requiredClass("dotty.tools.unshared"))
+    ctx.requiredClass("scala.annotation.internal.unshared"))
 
   def isIgnored(sym: Symbol)(implicit ctx: Context) =
     sym.hasAnnotation(sharableAnnot()) ||
@@ -92,4 +92,4 @@ class CheckReentrant extends MiniPhase {
       addVars(tree.symbol.owner.asClass)
     tree
   }
-}
+}

compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -37,6 +37,8 @@ import config.Printers.{implicits, implicitsDetailed, typr}
 import collection.mutable
 import reporting.trace
 
+import scala.annotation.internal.sharable
+
 /** Implicit resolution */
 object Implicits {
   import tpd._

compiler/src/dotty/tools/dotc/typer/Inferencing.scala

@@ -22,6 +22,8 @@ import reporting._
 import collection.mutable
 import config.Config
 
+import scala.annotation.internal.sharable
+
 object Inferencing {
 
   import tpd._

compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala

@@ -19,6 +19,8 @@ import ErrorReporting.errorType
 import config.Printers.typr
 import collection.mutable
 
+import scala.annotation.internal.sharable
+
 object ProtoTypes {
 
   import tpd._

compiler/src/dotty/tools/dotc/util/NameTransformer.scala

@@ -7,6 +7,8 @@ import core.Decorators._
 import collection.mutable
 import util.Chars.isValidJVMMethodChar
 
+import scala.annotation.internal.sharable
+
 /** Provides functions to encode and decode Scala symbolic names.
  */
 object NameTransformer {

compiler/src/dotty/tools/dotc/util/SourceFile.scala

@@ -11,6 +11,7 @@ import Chars._
 import ScriptSourceFile._
 import Positions._
 import scala.io.Codec
+import scala.annotation.internal.sharable
 
 import java.util.Optional
 

compiler/src/dotty/tools/dotc/util/SourcePosition.scala

@@ -4,6 +4,8 @@ package util
 
 import Positions.{Position, NoPosition}
 
+import scala.annotation.internal.sharable
+
 /** A source position is comprised of a position in a source file */
 case class SourcePosition(source: SourceFile, pos: Position, outer: SourcePosition = NoSourcePosition)
 extends interfaces.SourcePosition {

compiler/src/dotty/tools/dotc/util/Stats.scala

@@ -2,6 +2,8 @@ package dotty.tools
 package dotc
 package util
 
+import scala.annotation.internal.sharable
+
 import core.Contexts._
 import collection.mutable
 

compiler/src/dotty/tools/package.scala

@@ -2,9 +2,6 @@ package dotty
 import scala.annotation.Annotation
 
 package object tools {
-  class sharable extends Annotation
-  class unshared extends Annotation
-
   // Ensure this object is already classloaded, since it's only actually used
   // when handling stack overflows and every operation (including class loading)
   // risks failing.

compiler/src/dotty/tools/repl/ParseResult.scala

@@ -11,6 +11,8 @@ import dotc.reporting._
 
 import results._
 
+import scala.annotation.internal.sharable
+
 /** A parsing result from string input */
 sealed trait ParseResult
 

compiler/test/dotty/Jars.scala

@@ -18,6 +18,10 @@ object Jars {
   lazy val scalaAsm: String =
     findJarFromRuntime("scala-asm-6.0.0-scala-1")
 
+  /** scala-xml jar */
+  lazy val scalaXml: String =
+    findJarFromRuntime("scala-xml")
+
   /** JLine Jar */
   lazy val jline: String =
     findJarFromRuntime("jline-3.7.0")

compiler/test/dotty/TestCategories.scala

@@ -5,3 +5,6 @@ trait SlowTests
 
 /** Meta tests category for JUnit */
 trait VulpixMetaTests
+
+/** Tests that should only be run with a bootstrapped compiler */
+trait BootstrappedOnlyTests