9 files changed, 156 insertions, 5 deletions
diff --git a/test/files/pos/t8947/Client_2.scala b/test/files/pos/t8947/Client_2.scala
new file mode 100644
index 0000000000..1a5082a2f9
--- /dev/null
+++ b/test/files/pos/t8947/Client_2.scala
@@ -0,0 +1 @@
+object Test { X.extractor }
+\ No newline at end of file
diff --git a/test/files/pos/t8947/Macro_1.scala b/test/files/pos/t8947/Macro_1.scala
new file mode 100644
index 0000000000..4a5de3decb
--- /dev/null
+++ b/test/files/pos/t8947/Macro_1.scala
@@ -0,0 +1,41 @@
+import language.experimental.macros
+import scala.reflect.macros._
+import blackbox.Context
+
+object X {
+
+  def classTagOrNull[T](implicit t: reflect.ClassTag[T] = null) = t
+  // the failed search for ClassTag[T] does not issue a visible
+  // error as we fall back to the default argument. But, the
+  // macro engine things we have expanded the macro `materializeClassTag[D]()`
+  // to `EmptyTree`, and then attaches a backreference from the expansion
+  // to the expandee. This is the `MacroExpansionAttachment` tree attachment.
+  def foo[D] = classTagOrNull[D]
+
+  def extractor: Any = macro X.extractorMacro
+  def extractorMacro(c: Context): c.Expr[Any] = {
+    // Later, in reify, an unrelated use of `EmptyTree` in the AST representing
+    // the argument is now treated as a macro expansion which should be rolled
+    // back in the tree we reify! This ends up generating a call to `implicitly`
+    // which leads to an ambiguous error.
+    //
+    // Any macro call that expands to EmptyTree could have triggered this problem.
+    c.universe.reify(new { def something(data: Any) = ??? })
+  }
+
+  // Workarounds:
+  //
+  // 1. Use quasiquotes rather than `reify`. (But, beware to fully qualify all references, e.g. `_root_.scala.Predef.???`)
+  // 2. Avoid failed ClassTag lookups (e.g. in the original bug report, annotate the type argument to `map`)
+  // 3. In the macro implementation, just before calling the `reify` macro, you could call another macro
+  //
+  //      def prepareReify = macro prepareReifyImpl
+  //      def prepareReifyImpl(c: Context) = {
+  //        val symtab = c.universe.asInstanceOf[reflect.internal.SymbolTable]
+  //        symtab.EmptyTree.setAttachments(symtab.NoPosition)
+  //      }
+  //
+  //   To make this visible to the macro implementaiton, it will need to be compiled in an earlier stage,
+  //   e.g a separate SBT sub-project.
+
+}
diff --git a/test/files/pos/t8962.scala b/test/files/pos/t8962.scala
new file mode 100644
index 0000000000..4331c154ba
--- /dev/null
+++ b/test/files/pos/t8962.scala
@@ -0,0 +1,31 @@
+package test.nestedcov
+
+sealed abstract class Outer[+A]
+case class Let[+A](expr: Outer[Inner[A]]) extends Outer[A]
+
+sealed abstract class Inner[+A]
+
+sealed abstract class Outer2[+A, +B]
+case class Let2[+A](expr: Outer2[Inner2[A], A]) extends Outer2[A, A]
+
+sealed abstract class Inner2[+A]
+
+sealed abstract class Outer3[+A, +B]
+case class Let3[+A](expr: Outer3[A, A]) extends Outer3[A, A]
+
+object NestedCov {
+  def run[A](nc: Outer[A]) = nc match {
+    case Let(expr) =>
+      expr : Outer[Inner[A]]
+  }
+
+  def run2[A](nc: Outer2[A, A]) = nc match {
+    case Let2(expr) =>
+      expr : Outer2[Inner2[A], A]
+  }
+
+  def run3[A](nc: Outer3[A, A]) = nc match {
+    case Let3(expr) =>
+      expr : Outer3[A, A]
+  }
+}
diff --git a/test/files/run/delambdafy_uncurry_byname_inline.check b/test/files/run/delambdafy_uncurry_byname_inline.check
index 0dc69b379a..d96a995f44 100644
--- a/test/files/run/delambdafy_uncurry_byname_inline.check
+++ b/test/files/run/delambdafy_uncurry_byname_inline.check
@@ -7,7 +7,7 @@ package <empty> {
     };
     def bar(x: () => Int): Int = x.apply();
     def foo(): Int = Foo.this.bar({
-      @SerialVersionUID(0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction0[Int] with Serializable {
+      @SerialVersionUID(value = 0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction0[Int] with Serializable {
         def <init>(): <$anon: () => Int> = {
           $anonfun.super.<init>();
           ()
diff --git a/test/files/run/delambdafy_uncurry_inline.check b/test/files/run/delambdafy_uncurry_inline.check
index e2b024b462..5521cc4a2c 100644
--- a/test/files/run/delambdafy_uncurry_inline.check
+++ b/test/files/run/delambdafy_uncurry_inline.check
@@ -7,7 +7,7 @@ package <empty> {
     };
     def bar(): Unit = {
       val f: Int => Int = {
-        @SerialVersionUID(0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction1[Int,Int] with Serializable {
+        @SerialVersionUID(value = 0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction1[Int,Int] with Serializable {
           def <init>(): <$anon: Int => Int> = {
             $anonfun.super.<init>();
             ()
diff --git a/test/files/run/t6028.check b/test/files/run/t6028.check
index 55ff42d8d7..edc8b22d6d 100644
--- a/test/files/run/t6028.check
+++ b/test/files/run/t6028.check
@@ -24,7 +24,7 @@ package <empty> {
         (new <$anon: Function0>(T.this, tryyParam, tryyLocal): Function0)
       }
     };
-    @SerialVersionUID(0) final <synthetic> class $anonfun$foo$1 extends scala.runtime.AbstractFunction0$mcI$sp with Serializable {
+    @SerialVersionUID(value = 0) final <synthetic> class $anonfun$foo$1 extends scala.runtime.AbstractFunction0$mcI$sp with Serializable {
       def <init>($outer: T, methodParam$1: Int, methodLocal$1: Int): <$anon: Function0> = {
         $anonfun$foo$1.super.<init>();
         ()
@@ -60,7 +60,7 @@ package <empty> {
       };
       scala.this.Predef.print(scala.Int.box(barParam$1))
     };
-    @SerialVersionUID(0) final <synthetic> class $anonfun$tryy$1 extends scala.runtime.AbstractFunction0$mcV$sp with Serializable {
+    @SerialVersionUID(value = 0) final <synthetic> class $anonfun$tryy$1 extends scala.runtime.AbstractFunction0$mcV$sp with Serializable {
       def <init>($outer: T, tryyParam$1: Int, tryyLocal$1: runtime.IntRef): <$anon: Function0> = {
         $anonfun$tryy$1.super.<init>();
         ()
diff --git a/test/files/run/t6555.check b/test/files/run/t6555.check
index 9ac115a13f..e3b467ce7c 100644
--- a/test/files/run/t6555.check
+++ b/test/files/run/t6555.check
@@ -6,7 +6,7 @@ package <empty> {
       ()
     };
     private[this] val f: Int => Int = {
-      @SerialVersionUID(0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction1$mcII$sp with Serializable {
+      @SerialVersionUID(value = 0) final <synthetic> class $anonfun extends scala.runtime.AbstractFunction1$mcII$sp with Serializable {
         def <init>(): <$anon: Int => Int> = {
           $anonfun.super.<init>();
           ()
diff --git a/test/files/run/t8960.scala b/test/files/run/t8960.scala
new file mode 100644
index 0000000000..c6bcd0770c
--- /dev/null
+++ b/test/files/run/t8960.scala
@@ -0,0 +1,66 @@
+object Test extends App {
+  def test(o: AnyRef, sp: Boolean = false) = {
+    if (sp) assert(o.getClass.getSuperclass.getName contains "$sp")
+    val Some(f) = o.getClass.getDeclaredFields.find(_.getName == "serialVersionUID")
+    assert(f.getLong(null) == 0l)
+  }
+
+  test(() => (), sp = true)
+  test(() => 1,  sp = true)
+  test(() => "")
+
+  test((x: Int) => x, sp = true)
+  test((x: Boolean) => x)
+  test((x: Int) => "")
+
+  test((x1: Int, x2: Int) => 0d, sp = true)
+  test((x1: Int, x2: AnyRef) => 0d)
+  test((x1: Any, x2: Any) => x1)
+
+  // scala> println((for (i <- 3 to 22) yield (for (j <- 1 to i) yield s"x$j: Int").mkString("  test((", ", ", ") => x1)")).mkString("\n"))
+
+  test((x1: Int, x2: Int, x3: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int, x18: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int, x18: Int, x19: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int, x18: Int, x19: Int, x20: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int, x18: Int, x19: Int, x20: Int, x21: Int) => x1)
+  test((x1: Int, x2: Int, x3: Int, x4: Int, x5: Int, x6: Int, x7: Int, x8: Int, x9: Int, x10: Int, x11: Int, x12: Int, x13: Int, x14: Int, x15: Int, x16: Int, x17: Int, x18: Int, x19: Int, x20: Int, x21: Int, x22: Int) => x1)
+
+  test({
+    case x: Int => x
+  }: PartialFunction[Int, Int], sp = true)
+
+  test({
+    case x: Int => x
+  }: PartialFunction[Any, Any])
+
+  test({
+    case x: Int => ()
+  }: PartialFunction[Int, Unit], sp = true)
+
+  test({
+    case x: String => 1
+  }: PartialFunction[String, Int])
+
+  test({
+    case x: String => ()
+  }: PartialFunction[String, Unit])
+
+  test({
+    case x: String => x
+  }: PartialFunction[String, String])
+}
diff --git a/test/junit/scala/tools/nsc/symtab/CannotHaveAttrsTest.scala b/test/junit/scala/tools/nsc/symtab/CannotHaveAttrsTest.scala
index d424f12710..69931c9e24 100644
--- a/test/junit/scala/tools/nsc/symtab/CannotHaveAttrsTest.scala
+++ b/test/junit/scala/tools/nsc/symtab/CannotHaveAttrsTest.scala
@@ -64,4 +64,16 @@ class CannotHaveAttrsTest {
       assertThrows[IllegalArgumentException] { t.setType(tpe) }
     }
   }
+
+  class Attach
+  @Test
+  def attachmentsAreIgnored = {
+    attrlessTrees.foreach { t =>
+      t.setAttachments(NoPosition.update(new Attach))
+      assert(t.attachments == NoPosition)
+      t.updateAttachment(new Attach)
+      assert(t.attachments == NoPosition)
+      t.removeAttachment[Attach] // no exception
+    }
+  }
 }