transformers no longer ignore UnApply.fun

Second time's the charm. I remember trying to do exactly the same somewhen
around 2.10.0-M4, but then some continuations tests were failing.
Luckily, today everything went smoothly.

Please note that this fix changes the way that SI-5465 manifests itself.
Previously it produced type errors, now it simply crashes the compiler.
Therefore I had to attach the try/catch FatalError clause to invocations
of toolbox methods, so that compiler crashes get caught and translated to
ToolBoxErrors.

Also fixes SI-7871, and that clears the way for implementing quasiquotes
with conventional macros rather than relying on a special case in typer.

3 files changed, 34 insertions, 0 deletions

diff --git a/test/files/run/t7871.check b/test/files/run/t7871.check
new file mode 100644
index 0000000000..ce6efd812d
--- /dev/null
+++ b/test/files/run/t7871.check
@@ -0,0 +1 @@
+(SomeTree,SomeTree)
diff --git a/test/files/run/t7871/Macros_1.scala b/test/files/run/t7871/Macros_1.scala
new file mode 100644
index 0000000000..778068deb3
--- /dev/null
+++ b/test/files/run/t7871/Macros_1.scala
@@ -0,0 +1,27 @@
+import scala.reflect.macros.Context
+import language.experimental.macros
+
+trait Tree
+case object SomeTree extends Tree
+
+object NewQuasiquotes {
+  implicit class QuasiquoteInterpolation(c: StringContext) {
+    object nq {
+      def unapply(t: Tree) = macro QuasiquoteMacros.unapplyImpl
+    }
+  }
+}
+
+object QuasiquoteMacros {
+  def unapplyImpl(c: Context)(t: c.Tree) = {
+    import c.universe._
+    q"""
+      new {
+        def unapply(t: Tree) = t match {
+          case SomeTree => Some((SomeTree, SomeTree))
+          case _ => None
+        }
+      }.unapply($t)
+    """
+  }
+}
diff --git a/test/files/run/t7871/Test_2.scala b/test/files/run/t7871/Test_2.scala
new file mode 100644
index 0000000000..3a0b68b568
--- /dev/null
+++ b/test/files/run/t7871/Test_2.scala
@@ -0,0 +1,6 @@
+object Test extends App {
+  import NewQuasiquotes._
+  SomeTree match {
+    case nq"$x + $y" => println((x, y))
+  }
+}