Put more implementation restrictions on value classes.

Nested objects, classes and lazy vals are disallowed at any
nesting level in value classes; e.g. lazy vals local to a
method defined in a value class. There are still allowed in
universal traits.

This is a temporary, implementation restriction that is planned
to be addressed in future releases of Scala. Error messages has
been updated to communicate that intent.

Moved tests for SI-5582 and SI-6408 to pending folder. They have
to stay there until implementation restrictions are addressed.

Closes SI-6408 and SI-6432.

Review by @odersky, @harrah and @adriaanm.

1 files changed, 28 insertions, 0 deletions

diff --git a/test/files/neg/valueclasses-impl-restrictions.scala b/test/files/neg/valueclasses-impl-restrictions.scala
new file mode 100644
index 0000000000..53396db958
--- /dev/null
+++ b/test/files/neg/valueclasses-impl-restrictions.scala
@@ -0,0 +1,28 @@
+class M(val t: Int) extends AnyVal {
+   def lazyString = {
+      object X
+      lazy val y = 1
+      () => X
+   }
+}
+
+class X1(val s: String) extends AnyVal {
+  trait I2 {
+   val q: String
+   def z = s + q
+  }
+
+  def y(x: X1) = {
+    val i2 = new I2 { val q = x.s }
+    i2.z
+  }
+}
+
+class X2(val s: String) extends AnyVal {
+  private[this] class I2(val q: String)
+
+  def y(i: Int) = {
+    val i2 = new I2(i.toString)
+    i2.q + s
+  }
+}