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SI-6937 core type tags are no longer referentially unique
Type tag factory used to evaluate the provided type creator in the context of the initial mirror in order to maintain referential equality of instances of standard tags. Unfortunately this evaluation might fail if the mirror provided doesn't contain the classes being referred to. Therefore I think we should avoid evaluating type creators there. Note that failure of evaluation doesn't mean that there's something bad going on. When one creates a type tag, the correct mirror / classloader to interpret that tag in might be unknown (like it happens here). This is okay, and this is exactly what the 2.10.0-M4 refactoring has addressed. Something like `res2.typeTag[A].in(currentMirror)` should be okay.
1 parent 2894db7 commit c7a8172

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lines changed

‎src/reflect/scala/reflect/api/TypeTags.scala

Lines changed: 2 additions & 36 deletions
Original file line numberDiff line numberDiff line change
@@ -221,24 +221,7 @@ trait TypeTags { self: Universe =>
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def apply[T](mirror1: scala.reflect.api.Mirror[self.type], tpec1: TypeCreator): WeakTypeTag[T] =
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tpec1(mirror1) match {
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case ByteTpe => WeakTypeTag.Byte.asInstanceOf[WeakTypeTag[T]]
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case ShortTpe => WeakTypeTag.Short.asInstanceOf[WeakTypeTag[T]]
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case CharTpe => WeakTypeTag.Char.asInstanceOf[WeakTypeTag[T]]
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case IntTpe => WeakTypeTag.Int.asInstanceOf[WeakTypeTag[T]]
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case LongTpe => WeakTypeTag.Long.asInstanceOf[WeakTypeTag[T]]
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case FloatTpe => WeakTypeTag.Float.asInstanceOf[WeakTypeTag[T]]
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case DoubleTpe => WeakTypeTag.Double.asInstanceOf[WeakTypeTag[T]]
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case BooleanTpe => WeakTypeTag.Boolean.asInstanceOf[WeakTypeTag[T]]
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case UnitTpe => WeakTypeTag.Unit.asInstanceOf[WeakTypeTag[T]]
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case AnyTpe => WeakTypeTag.Any.asInstanceOf[WeakTypeTag[T]]
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case AnyValTpe => WeakTypeTag.AnyVal.asInstanceOf[WeakTypeTag[T]]
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case AnyRefTpe => WeakTypeTag.AnyRef.asInstanceOf[WeakTypeTag[T]]
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case ObjectTpe => WeakTypeTag.Object.asInstanceOf[WeakTypeTag[T]]
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case NothingTpe => WeakTypeTag.Nothing.asInstanceOf[WeakTypeTag[T]]
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case NullTpe => WeakTypeTag.Null.asInstanceOf[WeakTypeTag[T]]
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case _ => new WeakTypeTagImpl[T](mirror1.asInstanceOf[Mirror], tpec1)
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}
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new WeakTypeTagImpl[T](mirror1.asInstanceOf[Mirror], tpec1)
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def unapply[T](ttag: WeakTypeTag[T]): Option[Type] = Some(ttag.tpe)
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}
@@ -299,24 +282,7 @@ trait TypeTags { self: Universe =>
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val Null: TypeTag[scala.Null] = new PredefTypeTag[scala.Null] (NullTpe, _.TypeTag.Null)
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def apply[T](mirror1: scala.reflect.api.Mirror[self.type], tpec1: TypeCreator): TypeTag[T] =
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tpec1(mirror1) match {
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case ByteTpe => TypeTag.Byte.asInstanceOf[TypeTag[T]]
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case ShortTpe => TypeTag.Short.asInstanceOf[TypeTag[T]]
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case CharTpe => TypeTag.Char.asInstanceOf[TypeTag[T]]
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case IntTpe => TypeTag.Int.asInstanceOf[TypeTag[T]]
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case LongTpe => TypeTag.Long.asInstanceOf[TypeTag[T]]
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case FloatTpe => TypeTag.Float.asInstanceOf[TypeTag[T]]
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case DoubleTpe => TypeTag.Double.asInstanceOf[TypeTag[T]]
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case BooleanTpe => TypeTag.Boolean.asInstanceOf[TypeTag[T]]
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case UnitTpe => TypeTag.Unit.asInstanceOf[TypeTag[T]]
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case AnyTpe => TypeTag.Any.asInstanceOf[TypeTag[T]]
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case AnyValTpe => TypeTag.AnyVal.asInstanceOf[TypeTag[T]]
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case AnyRefTpe => TypeTag.AnyRef.asInstanceOf[TypeTag[T]]
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case ObjectTpe => TypeTag.Object.asInstanceOf[TypeTag[T]]
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case NothingTpe => TypeTag.Nothing.asInstanceOf[TypeTag[T]]
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case NullTpe => TypeTag.Null.asInstanceOf[TypeTag[T]]
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case _ => new TypeTagImpl[T](mirror1.asInstanceOf[Mirror], tpec1)
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}
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new TypeTagImpl[T](mirror1.asInstanceOf[Mirror], tpec1)
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def unapply[T](ttag: TypeTag[T]): Option[Type] = Some(ttag.tpe)
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}

‎test/files/run/macro-expand-tparams-explicit.check

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1 +1 @@
1-
TypeTag[Int]
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WeakTypeTag[Int]

‎test/files/run/macro-expand-tparams-implicit.check

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,2 +1,2 @@
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]

‎test/files/run/macro-expand-tparams-prefix.check

Lines changed: 17 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -1,39 +1,39 @@
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===Macros1 typed===
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TypeTag[Int]
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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===Macros1 untyped===
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WeakTypeTag[U]
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WeakTypeTag[U]
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WeakTypeTag[U]
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WeakTypeTag[U]
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===Macros2 typed===
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TypeTag[Boolean] TypeTag[Int]
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TypeTag[Boolean] WeakTypeTag[String]
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WeakTypeTag[Boolean] WeakTypeTag[Int]
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WeakTypeTag[Boolean] WeakTypeTag[String]
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===Macros2 untyped===
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TypeTag[Boolean] WeakTypeTag[U]
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TypeTag[Boolean] WeakTypeTag[U]
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WeakTypeTag[Boolean] WeakTypeTag[U]
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WeakTypeTag[Boolean] WeakTypeTag[U]
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===Macros3 typed===
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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===Macros3 untyped===
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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===Macros4 typed===
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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===Macros4 untyped===
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TypeTag[Int]
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WeakTypeTag[Int]
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WeakTypeTag[String]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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===Macros5 typed and untyped===
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WeakTypeTag[T]
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WeakTypeTag[U]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]
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WeakTypeTag[T]
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WeakTypeTag[U]
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TypeTag[Boolean]
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WeakTypeTag[Boolean]

‎test/files/run/macro-undetparams-consfromsls.check

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
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A = TypeTag[Int]
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B = TypeTag[Nothing]
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A = WeakTypeTag[Int]
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B = WeakTypeTag[Nothing]
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List(1)
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A = TypeTag[Any]
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A = WeakTypeTag[Any]
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List(abc, 1)

‎test/files/run/macro-undetparams-macroitself.check

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,2 +1,2 @@
1-
TypeTag[Int]
1+
WeakTypeTag[Int]
22
WeakTypeTag[String]

‎test/files/run/t6937.check

Lines changed: 26 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,26 @@
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Type in expressions to have them evaluated.
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Type :help for more information.
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scala>
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scala> import scala.reflect.runtime.{universe => ru}
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import scala.reflect.runtime.{universe=>ru}
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scala> import scala.reflect.runtime.{currentMirror => cm}
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import scala.reflect.runtime.{currentMirror=>cm}
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scala> import scala.reflect.api.{Universe => ApiUniverse}
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import scala.reflect.api.{Universe=>ApiUniverse}
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scala> class A
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defined class A
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scala> lazy val apiru = ru: ApiUniverse
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apiru: scala.reflect.api.Universe = <lazy>
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scala> apiru.typeTag[A].in(cm)
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res0: reflect.runtime.universe.TypeTag[A] = TypeTag[A]
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scala>
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scala>

‎test/files/run/t6937.scala

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
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import scala.tools.partest.ReplTest
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object Test extends ReplTest {
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def code = """
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import scala.reflect.runtime.{universe => ru}
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import scala.reflect.runtime.{currentMirror => cm}
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import scala.reflect.api.{Universe => ApiUniverse}
8+
class A
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lazy val apiru = ru: ApiUniverse
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apiru.typeTag[A].in(cm)
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"""
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}

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