blackbox restriction #1: can't refine the official return type

When an application of a blackbox macro expands into a tree `x`,
the expansion is wrapped into a type ascription `(x: T)`, where `T` is
the declared return type of the blackbox macro with type arguments and
path dependencies applied in consistency with the particular macro
application being expanded.

This invalidates blackbox macros as an implementation vehicle
of type providers.

2 files changed, 20 insertions, 0 deletions

diff --git a/test/files/neg/macro-blackbox-structural/Impls_Macros_1.scala b/test/files/neg/macro-blackbox-structural/Impls_Macros_1.scala
new file mode 100644
index 0000000000..08f1c21e89
--- /dev/null
+++ b/test/files/neg/macro-blackbox-structural/Impls_Macros_1.scala
@@ -0,0 +1,15 @@
+import scala.language.experimental.macros
+
+object Macros {
+  def impl(c: scala.reflect.macros.BlackboxContext) = {
+    import c.universe._
+    q"""
+      trait Foo {
+        def x = 2
+      }
+      new Foo {}
+    """
+  }
+
+  def foo = macro impl
+}
\ No newline at end of file
diff --git a/test/files/neg/macro-blackbox-structural/Test_2.scala b/test/files/neg/macro-blackbox-structural/Test_2.scala
new file mode 100644
index 0000000000..ea6a817e34
--- /dev/null
+++ b/test/files/neg/macro-blackbox-structural/Test_2.scala
@@ -0,0 +1,5 @@
+import Macros._
+
+object Test extends App {
+  println(Macros.foo.x)
+}
\ No newline at end of file