Fix #4342: Adapt outer types when calling into Scala 2 classes

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

@@ -1678,7 +1678,7 @@ object SymDenotations {
           case tp @ AppliedType(tycon, args) =>
             val subsym = tycon.typeSymbol
             if (subsym eq symbol) tp
-            else tycon.typeParams match {
+            else (tycon.typeParams: @unchecked) match {
               case LambdaParam(_, _) :: _ =>
                 baseTypeOf(tp.superType)
               case tparams: List[Symbol @unchecked] =>

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

@@ -2674,7 +2674,7 @@ object Types {
      *  either a list of type parameter symbols or a list of lambda parameters
      */
     def integrate(tparams: List[ParamInfo], tp: Type)(implicit ctx: Context): Type =
-      tparams match {
+      (tparams: @unchecked) match {
         case LambdaParam(lam, _) :: _ => tp.subst(lam, this)
         case params: List[Symbol @unchecked] => tp.subst(params, paramRefs)
       }

compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala

@@ -295,8 +295,12 @@ private class ExtractDependenciesCollector extends tpd.TreeTraverser { thisTreeT
       val fromClass = resolveDependencySource
       if (fromClass.exists) { // can happen when visiting imports
         assert(fromClass.isClass)
-        _dependencies += ClassDependency(fromClass, enclOrModuleClass, DependencyByMemberRef)
+
         addUsedName(fromClass, mangledName(sym), UseScope.Default)
+        // packages have class symbol. Only record them as used names but not dependency
+        if (!sym.is(Package)) {
+          _dependencies += ClassDependency(fromClass, enclOrModuleClass, DependencyByMemberRef)
+        }
       }
     }
 
@@ -315,7 +319,6 @@ private class ExtractDependenciesCollector extends tpd.TreeTraverser { thisTreeT
     !sym.exists ||
     sym.unforcedIsAbsent || // ignore dependencies that have a symbol but do not exist.
                             // e.g. java.lang.Object companion object
-    sym.is(PackageClass) ||
     sym.isEffectiveRoot ||
     sym.isAnonymousFunction ||
     sym.isAnonymousClass

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

@@ -88,7 +88,7 @@ class ExpandSAMs extends MiniPhase {
     cpy.Block(tree)(List(applyDef, isDefinedAtDef), anonCls)
   }
 
-  private def checkRefinements(tpe: Type, pos: Position)(implicit ctx: Context): Type = tpe match {
+  private def checkRefinements(tpe: Type, pos: Position)(implicit ctx: Context): Type = tpe.dealias match {
     case RefinedType(parent, name, _) =>
       if (name.isTermName && tpe.member(name).symbol.ownersIterator.isEmpty) // if member defined in the refinement
         ctx.error("Lambda does not define " + name, pos)

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

@@ -141,6 +141,20 @@ object ExplicitOuter {
   private def newOuterAccessors(cls: ClassSymbol)(implicit ctx: Context) =
     newOuterAccessor(cls, cls) :: (if (cls is Trait) Nil else newOuterParamAccessor(cls) :: Nil)
 
+  /** Scala 2.x and Dotty don't always agree on what should be the type of the outer parameter,
+   *  so we replicate the old behavior when passing arguments to methods coming from Scala 2.x.
+   */
+  private def outerClass(cls: ClassSymbol)(implicit ctx: Context): Symbol = {
+    val encl = cls.owner.enclosingClass
+    if (cls.is(Scala2x))
+      encl.asClass.classInfo.selfInfo match {
+        case tp: TypeRef => tp.classSymbol
+        case self: Symbol => self
+        case _ => encl
+      }
+    else encl
+  }
+
   /** A new outer accessor or param accessor.
    *  @param  owner  The class where the outer accessor is located
    *  @param  cls    The class relative to which the outer is computed (can be a base class of owner)
@@ -156,7 +170,7 @@ object ExplicitOuter {
    */
   private def newOuterSym(owner: ClassSymbol, cls: ClassSymbol, name: TermName, flags: FlagSet)(implicit ctx: Context) = {
     val outerThis = owner.owner.enclosingClass.thisType
-    val outerCls = cls.owner.enclosingClass
+    val outerCls = outerClass(cls)
     val target =
       if (owner == cls)
         outerCls.appliedRef
@@ -341,7 +355,7 @@ object ExplicitOuter {
       if (hasOuterParam(cls)) {
         val mt @ MethodTpe(pnames, ptypes, restpe) = tp
         mt.derivedLambdaType(
-          nme.OUTER :: pnames, cls.owner.enclosingClass.typeRef :: ptypes, restpe)
+          nme.OUTER :: pnames, outerClass(cls).typeRef :: ptypes, restpe)
       } else tp
 
     /** If function in an apply node is a constructor that needs to be passed an

compiler/src/dotty/tools/dotc/transform/patmat/Space.scala

@@ -113,6 +113,7 @@ trait SpaceLogic {
     case Prod(tp, fun, sym, spaces, full) =>
       val sp = Prod(tp, fun, sym, spaces.map(simplify(_)), full)
       if (sp.params.contains(Empty)) Empty
+      else if (canDecompose(tp) && decompose(tp).isEmpty) Empty
       else sp
     case Or(spaces) =>
       val set = spaces.map(simplify(_)).flatMap {
@@ -349,18 +350,19 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
       Empty
   }
 
-  /* Erase a type binding according to erasure semantics in pattern matching */
-  def erase(tp: Type): Type = tp match {
-    case tp @ AppliedType(tycon, args) =>
-      if (tycon.isRef(defn.ArrayClass)) tp.derivedAppliedType(tycon, args.map(erase))
-      else tp.derivedAppliedType(tycon, args.map(t => WildcardType))
-    case OrType(tp1, tp2) =>
-      OrType(erase(tp1), erase(tp2))
-    case AndType(tp1, tp2) =>
-      AndType(erase(tp1), erase(tp2))
-    case tp @ RefinedType(parent, refinedName, _) if refinedName.isTermName =>   // see pos/dependent-extractors.scala
-      tp.derivedRefinedType(erase(parent), refinedName, WildcardType)
-    case _ => tp
+  /* Erase pattern bound types with WildcardType */
+  def erase(tp: Type) = {
+    def isPatternTypeSymbol(sym: Symbol) = !sym.isClass && sym.is(Case)
+
+    val map = new TypeMap {
+      def apply(tp: Type) = tp match {
+        case tref: TypeRef if isPatternTypeSymbol(tref.typeSymbol) =>
+          tref.underlying.bounds
+        case _ => mapOver(tp)
+      }
+    }
+
+    map(tp)
   }
 
   /** Space of the pattern: unapplySeq(a, b, c: _*)
@@ -384,7 +386,7 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
   /** Is `tp1` a subtype of `tp2`?  */
   def isSubType(tp1: Type, tp2: Type): Boolean = {
     val res = (tp1 != nullType || tp2 == nullType) && tp1 <:< tp2
-    debug.println(s"${tp1.show} <:< ${tp2.show} = $res")
+    debug.println(s"${tp1} <:< ${tp2} = $res")
     res
   }
 
@@ -587,8 +589,8 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
           noClassConflict &&
             (!isSingleton(tp1) || tp1 <:< tp2) &&
             (!isSingleton(tp2) || tp2 <:< tp1) &&
-            (!bases1.exists(_ is Final) || tp1 <:< tp2) &&
-            (!bases2.exists(_ is Final) || tp2 <:< tp1)
+            (!bases1.exists(_ is Final) || tp1 <:< maxTypeMap.apply(tp2)) &&
+            (!bases2.exists(_ is Final) || tp2 <:< maxTypeMap.apply(tp1))
         }
       case OrType(tp1, tp2) =>
         recur(tp1) || recur(tp2)
@@ -607,6 +609,41 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
     res
   }
 
+  /** expose abstract type references to their bounds or tvars according to variance */
+  private class AbstractTypeMap(maximize: Boolean)(implicit ctx: Context) extends TypeMap {
+    def expose(lo: Type, hi: Type): Type =
+      if (variance == 0)
+        newTypeVar(TypeBounds(lo, hi))
+      else if (variance == 1)
+        if (maximize) hi else lo
+      else
+        if (maximize) lo else hi
+
+    def apply(tp: Type): Type = tp match {
+      case tp: TypeRef if tp.underlying.isInstanceOf[TypeBounds] =>
+        val lo = this(tp.info.loBound)
+        val hi = this(tp.info.hiBound)
+        // See tests/patmat/gadt.scala  tests/patmat/exhausting.scala  tests/patmat/t9657.scala
+        val exposed = expose(lo, hi)
+        debug.println(s"$tp exposed to =====> $exposed")
+        exposed
+
+      case AppliedType(tycon: TypeRef, args) if tycon.underlying.isInstanceOf[TypeBounds] =>
+        val args2 = args.map(this)
+        val lo = this(tycon.info.loBound).applyIfParameterized(args2)
+        val hi = this(tycon.info.hiBound).applyIfParameterized(args2)
+        val exposed = expose(lo, hi)
+        debug.println(s"$tp exposed to =====> $exposed")
+        exposed
+
+      case _ =>
+        mapOver(tp)
+    }
+  }
+
+  private def minTypeMap(implicit ctx: Context) = new AbstractTypeMap(maximize = false)
+  private def maxTypeMap(implicit ctx: Context) = new AbstractTypeMap(maximize = true)
+
   /** Instantiate type `tp1` to be a subtype of `tp2`
    *
    *  Return the instantiated type if type parameters and this type
@@ -616,25 +653,6 @@ class SpaceEngine(implicit ctx: Context) extends SpaceLogic {
    *
    */
   def instantiate(tp1: NamedType, tp2: Type)(implicit ctx: Context): Type = {
-    // expose type param references to their bounds according to variance
-    class AbstractTypeMap(maximize: Boolean)(implicit ctx: Context) extends ApproximatingTypeMap {
-      variance = if (maximize) 1 else -1
-
-      def apply(tp: Type): Type = tp match {
-        case tp: TypeRef if tp.underlying.isInstanceOf[TypeBounds] =>
-          val lo = this(tp.info.loBound)
-          val hi = this(tp.info.hiBound)
-          // See tests/patmat/gadt.scala  tests/patmat/exhausting.scala  tests/patmat/t9657.scala
-          range(lo, hi)
-
-        case _ =>
-          mapOver(tp)
-      }
-    }
-
-    def minTypeMap(implicit ctx: Context) = new AbstractTypeMap(maximize = false)
-    def maxTypeMap(implicit ctx: Context) = new AbstractTypeMap(maximize = true)
-
     // Fix subtype checking for child instantiation,
     // such that `Foo(Test.this.foo) <:< Foo(Foo.this)`
     // See tests/patmat/i3938.scala

project/Build.scala

@@ -900,7 +900,7 @@ object Build {
     settings(commonSettings).
     settings(
       EclipseKeys.skipProject := true,
-      version := "0.1.3", // Keep in sync with package.json
+      version := "0.1.4", // Keep in sync with package.json
       autoScalaLibrary := false,
       publishArtifact := false,
       includeFilter in unmanagedSources := NothingFilter | "*.ts" | "**.json",

sbt-bridge/test/xsbt/DependencySpecification.scala

@@ -145,6 +145,25 @@ class DependencySpecification {
     assertEquals(Set("abc.A"), deps("H"))
   }
 
+  @Test
+  def extractedClassDependenciesOnPackageObject = {
+    val srcA = "package object foo { def bar = 1 }"
+    val srcB =
+      """|package foo
+         |
+         |class Test {
+         |  bar
+         |}
+      """.stripMargin
+
+    val compilerForTesting = new ScalaCompilerForUnitTesting
+    val classDependencies =
+      compilerForTesting.extractDependenciesFromSrcs(srcA, srcB)
+
+    val memberRef = classDependencies.memberRef
+    assertEquals(Set("foo.package"), memberRef("foo.Test"))
+  }
+
   private def extractClassDependenciesPublic: ExtractedClassDependencies = {
     val srcA = "class A"
     val srcB = "class B extends D[A]"

sbt-bridge/test/xsbt/ExtractUsedNamesSpecification.scala

@@ -275,6 +275,21 @@ class ExtractUsedNamesSpecification {
     assertEquals(Set(), findPatMatUsages(notUsedInPatternMatch))
   }
 
+  @Test
+  def extractedNamesInImport = {
+    val src =
+      """|import java.util.List
+         |
+         |class Test
+      """.stripMargin
+
+    val compilerForTesting = new ScalaCompilerForUnitTesting
+    val usedNames = compilerForTesting.extractUsedNamesFromSrc(src)
+
+    val expectedNames = standardNames ++ Set("java", "util", "List")
+    assertEquals(expectedNames, usedNames("Test"))
+  }
+
   /**
    * Standard names that appear in every compilation unit that has any class
    * definition.

sbt-dotty/sbt-test/source-dependencies/package-object-implicit/Test.scala

@@ -0,0 +1,6 @@
+package foo
+
+object Test {
+  def test(implicit x: Int = 1): String = x.toString
+  def main(args: Array[String]): Unit = test
+}

sbt-dotty/sbt-test/source-dependencies/package-object-implicit/changes/package.scala

@@ -0,0 +1,3 @@
+package object foo {
+  implicit val x: Int = ???
+}

sbt-dotty/sbt-test/source-dependencies/package-object-implicit/pending

@@ -0,0 +1,7 @@
+> run
+
+$ copy-file changes/package.scala package.scala
+
+# New implicit in scope from package object that makes run throws
+# clean run fails correctly
+-> run

sbt-dotty/sbt-test/source-dependencies/package-object-implicit/project/DottyInjectedPlugin.scala

@@ -0,0 +1,12 @@
+import sbt._
+import Keys._
+
+object DottyInjectedPlugin extends AutoPlugin {
+  override def requires = plugins.JvmPlugin
+  override def trigger = allRequirements
+
+  override val projectSettings = Seq(
+    scalaVersion := sys.props("plugin.scalaVersion"),
+    scalacOptions += "-language:Scala2"
+  )
+}

sbt-dotty/sbt-test/source-dependencies/package-object-implicit/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % sys.props("plugin.version"))

tests/pos-special/isInstanceOf/t2755.scala → tests/neg-custom-args/isInstanceOf/t2755.scala

@@ -17,7 +17,7 @@ object Test {
     case x: Array[String]   => x.size
     case x: Array[AnyRef]   => 5
     case x: Array[_]        => 6
-    case _                  => 7
+    case _                  => 7   // error: only null is matched
   }
   def f3[T](a: Array[T]) = a match {
     case x: Array[Int]      => x(0)
@@ -26,7 +26,7 @@ object Test {
     case x: Array[String]   => x.size
     case x: Array[AnyRef]   => 5
     case x: Array[_]        => 6
-    case _                  => 7
+    case _                  => 7   // error: only null is matched
   }
 
 

tests/neg/i4339.scala

@@ -0,0 +1,19 @@
+class Test {
+  def test: Unit = {
+    val a: PartialFunction[Int, Int]{ def foo: Int } = { case x => x } // error
+
+    type PF = PartialFunction[Int, Int] { def foo: Int }
+    val b: PF = { case x => x } // error
+
+    type PF1 = PartialFunction[Int, Int] {def foo: Int }
+    val c: PF1 {} = { case x => x } // error
+
+    type PF2 = PartialFunction[Int, Int]
+    val d: PF2 {} = { case x => x }
+
+    type PF3 = PartialFunction[Int, Int] {}
+    val e: PF3 = { case x => x }
+
+    val f: PartialFunction[Int, Int] {} { def foo: Int } = { case x => x } // error
+  }
+}

tests/patmat/i4314.scala

@@ -0,0 +1,10 @@
+sealed trait Foo[A]
+case class One[A]() extends Foo[A]
+sealed abstract case class Bar[A]() extends Foo[A]
+class Two() extends Bar[String]
+
+object Test {
+  def test(x: Foo[Int]) = x match {
+    case One() =>
+  }
+}

tests/patmat/i4314b.check

@@ -0,0 +1 @@
+9: Match case Unreachable

tests/patmat/i4314b.scala

@@ -0,0 +1,11 @@
+sealed trait Foo[A]
+case class One[A]() extends Foo[A]
+sealed abstract case class Bar[A]() extends Foo[A]
+class Two() extends Bar[String]
+
+object Test {
+  def test(x: Foo[Int]) = x match {
+    case One() =>
+    case Bar() =>
+  }
+}