SI-5903 extractor macros do work

Apparently it is already possible to use macros to customize pattern
matching as described in the comments to the aforementioned JIRA issue.

What's even better - with the incoming addition of c.introduceTopLevel
it becomes possible to generate arbitrarily complex unappliers, even
with heterogeneous types of arguments varying from expansion to expansion

2 files changed, 21 insertions, 0 deletions

diff --git a/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala b/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala
new file mode 100644
index 0000000000..61d6345f16
--- /dev/null
+++ b/test/files/run/macro-expand-unapply-a/Impls_Macros_1.scala
@@ -0,0 +1,15 @@
+import scala.reflect.macros.Context
+
+object Helper {
+  def unapplySeq[T](x: List[T]): Option[Seq[T]] = List.unapplySeq[T](x)
+}
+
+object Macros {
+  def impl[T: c.WeakTypeTag](c: Context)(x: c.Expr[List[T]]) = {
+    c.universe.reify(Helper.unapplySeq(x.splice))
+  }
+
+  object UnapplyMacro {
+    def unapplySeq[T](x: List[T]): Option[Seq[T]] = macro impl[T]
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/macro-expand-unapply-a/Test_2.scala b/test/files/run/macro-expand-unapply-a/Test_2.scala
new file mode 100644
index 0000000000..6169d86b19
--- /dev/null
+++ b/test/files/run/macro-expand-unapply-a/Test_2.scala
@@ -0,0 +1,6 @@
+import Macros._
+
+object Test extends App {
+  List(1, 2) match { case UnapplyMacro(x, y) => println((x, y)) }
+  List(1, 2, 3) match { case UnapplyMacro(x, y, z) => println((x, y, z)) }
+}
\ No newline at end of file