Handle @specializec(AnyRef) by not specializing

Author: AlexSikia

src/dotty/tools/dotc/Compiler.scala

@@ -122,4 +122,4 @@ class Compiler {
     reset()
     new Run(this)(rootContext)
   }
-}
+}

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

@@ -33,7 +33,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val usejavacp = BooleanSetting("-usejavacp", "Utilize the java.class.path in classpath resolution.")
   val verbose = BooleanSetting("-verbose", "Output messages about what the compiler is doing.")
   val version = BooleanSetting("-version", "Print product version and exit.")
-  val pageWidth = IntSetting("-pagewidth", "Set page width", 160)
+  val pageWidth = IntSetting("-pagewidth", "Set page width", 80)
 
   val jvmargs = PrefixSetting("-J<flag>", "-J", "Pass <flag> directly to the runtime system.")
   val defines = PrefixSetting("-Dproperty=value", "-D", "Pass -Dproperty=value directly to the runtime system.")

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

@@ -317,10 +317,10 @@ class Definitions {
   lazy val LanguageModuleClass          = ctx.requiredModule("dotty.language").moduleClass.asClass
 
   // Annotation base classes
-  lazy val AnnotationClass               = ctx.requiredClass("scala.annotation.Annotation")
-  lazy val ClassfileAnnotationClass      = ctx.requiredClass("scala.annotation.ClassfileAnnotation")
-  lazy val StaticAnnotationClass         = ctx.requiredClass("scala.annotation.StaticAnnotation")
-  lazy val TailrecAnnotationClass        = ctx.requiredClass("scala.annotation.tailrec")
+  lazy val AnnotationClass              = ctx.requiredClass("scala.annotation.Annotation")
+  lazy val ClassfileAnnotationClass     = ctx.requiredClass("scala.annotation.ClassfileAnnotation")
+  lazy val StaticAnnotationClass        = ctx.requiredClass("scala.annotation.StaticAnnotation")
+  lazy val TailrecAnnotationClass       = ctx.requiredClass("scala.annotation.tailrec")
   lazy val RemoteAnnot                   = ctx.requiredClass("scala.remote")
   lazy val SerialVersionUIDAnnot         = ctx.requiredClass("scala.SerialVersionUID")
   lazy val TransientAnnot                = ctx.requiredClass("scala.transient")

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

@@ -7,7 +7,7 @@ import dotty.tools.dotc.core.Contexts.Context
 import dotty.tools.dotc.core.StdNames._
 import dotty.tools.dotc.core.{Flags, Definitions}
 import dotty.tools.dotc.core.Symbols.Symbol
-import dotty.tools.dotc.core.Types.Type
+import dotty.tools.dotc.core.Types.{TermRef, Type}
 import dotty.tools.dotc.transform.TreeTransforms.{TransformerInfo, MiniPhaseTransform}
 
 /**
@@ -19,9 +19,14 @@ class PreSpecializer extends MiniPhaseTransform {
   override def phaseName: String = "prespecialize"
 
   private final def primitiveCompanionToPrimitive(companion: Type)(implicit ctx: Context) = {
-    val claz = companion.termSymbol.companionClass
-    assert(ctx.definitions.ScalaValueClasses.contains(claz))
-    claz.typeRef
+    if (companion.asInstanceOf[TermRef].name.toString == "AnyRef") { // Handles `@specialized(AnyRef)` cases
+      Nil
+    }
+    else {
+      val claz = companion.termSymbol.companionClass
+      assert(ctx.definitions.ScalaValueClasses.contains(claz))
+      claz.typeRef :: Nil
+    }
   }
 
   def defn(implicit ctx: Context): Definitions = ctx.definitions
@@ -55,8 +60,11 @@ class PreSpecializer extends MiniPhaseTransform {
           val args = annot.arguments
           if (args.isEmpty) primitiveTypes
           else args.head match {
-            case a@Typed(SeqLiteral(types), _) => types.map(t => primitiveCompanionToPrimitive(t.tpe)) // Matches the expected `@specialized(...)` annotations
-            case a@Select(Ident(_), _)         => primitiveTypes  // Matches `Select(Ident(Specializable), Primitives)` which is used in several instances
+            case a@Typed(SeqLiteral(types), _) =>  // Matches the expected `@specialized(...)` annotations
+              types.map(t => primitiveCompanionToPrimitive(t.tpe)).flatten
+
+            case a@Select(Ident(_), _)         => primitiveTypes  // Matches `Select(Ident(Specializable), Primitives)`
+                                                                  // which is used in several instances in the compiler
             case _ => ctx.error("surprising match on specialized annotation"); Nil
           }
         case nil => Nil

test/dotc/tests.scala

@@ -14,14 +14,14 @@ class tests extends CompilerTest {
 //        "-Xprompt",
 //        "-explaintypes",
 //        "-Yshow-suppressed-errors",
-  )
+        "-pagewidth", "160")
 
   val defaultOutputDir = "./out/"
 
   implicit val defaultOptions = noCheckOptions ++ List(
-     "-Yno-deep-subtypes", "-Yno-double-bindings",
-     "-Ycheck:tailrec,resolveSuper,mixin,restoreScopes",
-     "-d", defaultOutputDir
+      "-Yno-deep-subtypes", "-Yno-double-bindings",
+      "-Ycheck:tailrec,resolveSuper,mixin,restoreScopes",
+      "-d", defaultOutputDir
   )
   val testPickling = List("-Xprint-types", "-Ytest-pickler", "-Ystop-after:pickler")
 
@@ -50,7 +50,6 @@ class tests extends CompilerTest {
   val dotcDir   = toolsDir + "dotc/"
   val coreDir   = dotcDir + "core/"
 
-
   @Test def pickle_pickleOK = compileDir(testsDir, "pickling", testPickling)
 // This directory doesn't exist anymore
 // @Test def pickle_pickling = compileDir(coreDir, "pickling", testPickling)
@@ -168,9 +167,9 @@ class tests extends CompilerTest {
   @Test def dotc_reporting = compileDir(dotcDir, "reporting") // twice omitted to make tests run faster
 
   @Test def dotc_typer = compileDir(dotcDir, "typer")// twice omitted to make tests run faster
- // error: error while loading Checking$$anon$2$,
- // class file 'target/scala-2.11/dotty_2.11-0.1-SNAPSHOT.jar(dotty/tools/dotc/typer/Checking$$anon$2.class)'
- // has location not matching its contents: contains class $anon
+    // error: error while loading Checking$$anon$2$,
+    // class file 'target/scala-2.11/dotty_2.11-0.1-SNAPSHOT.jar(dotty/tools/dotc/typer/Checking$$anon$2.class)'
+    // has location not matching its contents: contains class $anon
 
   @Test def dotc_util = compileDir(dotcDir, "util") // twice omitted to make tests run faster
 
@@ -181,15 +180,15 @@ class tests extends CompilerTest {
   //@Test def tools = compileDir(dottyDir, "tools", "-deep" :: Nil)(allowDeepSubtypes)
 
   @Test def testNonCyclic = compileList("testNonCyclic", List(
-     dotcDir + "CompilationUnit.scala",
-     coreDir + "Types.scala",
-     dotcDir + "ast/Trees.scala"
-   ), List("-Xprompt") ++ staleSymbolError ++ twice)
+      dotcDir + "CompilationUnit.scala",
+      coreDir + "Types.scala",
+      dotcDir + "ast/Trees.scala"
+    ), List("-Xprompt") ++ staleSymbolError ++ twice)
 
   @Test def testIssue_34 = compileList("testIssue_34", List(
-     dotcDir + "config/Properties.scala",
-     dotcDir + "config/PathResolver.scala"
-   ), List(/* "-Ylog:frontend", */ "-Xprompt") ++ staleSymbolError ++ twice)
+      dotcDir + "config/Properties.scala",
+      dotcDir + "config/PathResolver.scala"
+    ), List(/* "-Ylog:frontend", */ "-Xprompt") ++ staleSymbolError ++ twice)
 
   val javaDir = "./tests/pos/java-interop/"
   @Test def java_all = compileFiles(javaDir, twice)