diff options
Diffstat (limited to 'test/files/neg/t8104')
-rw-r--r-- | test/files/neg/t8104/Macros_1.scala | 11 | ||||
-rw-r--r-- | test/files/neg/t8104/Test_2.scala | 21 |
2 files changed, 32 insertions, 0 deletions
diff --git a/test/files/neg/t8104/Macros_1.scala b/test/files/neg/t8104/Macros_1.scala new file mode 100644 index 0000000000..21d81a3687 --- /dev/null +++ b/test/files/neg/t8104/Macros_1.scala @@ -0,0 +1,11 @@ +import scala.reflect.macros.WhiteboxContext + +object Macros { + def impl[T](c: WhiteboxContext)(implicit T: c.WeakTypeTag[T]) = { + import c.universe._ + import definitions._ + val fields = T.tpe.declarations.toList.collect{ case x: TermSymbol if x.isVal && x.isCaseAccessor => x } + val Repr = appliedType(TupleClass(fields.length).asType.toType, fields.map(_.typeSignature)) + q"new Generic[$T]{ type Repr = $Repr }" + } +}
\ No newline at end of file diff --git a/test/files/neg/t8104/Test_2.scala b/test/files/neg/t8104/Test_2.scala new file mode 100644 index 0000000000..585f76c00f --- /dev/null +++ b/test/files/neg/t8104/Test_2.scala @@ -0,0 +1,21 @@ +trait Generic[T] { type Repr } +object Generic { + type Aux[T, Repr0] = Generic[T] { type Repr = Repr0 } + import scala.language.experimental.macros + implicit def materializeGeneric[T]: Generic[T] = macro Macros.impl[T] +} + +object Test extends App { + case class C(x: Int, y: Int) + + import scala.reflect.runtime.universe._ + def reprify[T, Repr](x: T)(implicit generic: Generic.Aux[T, Repr], tag: TypeTag[Repr]) = println(tag) + reprify(C(40, 2)) + + // this is a compilation error at the moment as explained in SI-8104 + // because matchesPt in implicit search says that depoly(<type of materializeGeneric>) isn't a subtype of Generic.Aux[C, (Int, Int)] + // which is rightfully so, because depoly only replaces type parameters, not type members with wildcard types + // however in the future we might want to relax the matchesPt check, so this might start compiling + // therefore, if you've broken this test, then you should be happy, because most likely you've just enabled an interesting use case! + implicitly[Generic.Aux[C, (Int, Int)]] +} |