SI-6666 Account for nesting in setting INCONSTRUCTOR

This flag is calcualed in Namers, and assigned to class
and module class symbols that are defined in self/super-calls,
and in early definitions.

For example, class D is INCONSTRUCTOR in each case below:

    class C extends Super({class D; ()})
    class C(a: Any) {
      def this(a: Any) = this({class D; ()})
    }
    new { val x = { class D; () } with Super(())

But, the calculation of this flag failed to account for
nesting, so it was not set in cases like:

    class C(a: Any) {
      def this(a: Any) = this({val x = {class D; ()}; x})
    }

This patch searches the enclosing context chain, rather than
just the immediate context. The search is terminated at the
first non term-owned context. In the following example, this
avoids marking `E` as INCONSTRUCTOR; only `D` should be.

    class C extends Super({class D { class E }; ()})

This closes SI-6259 and SI-6506, and fixes one problem
in the recently reopened SI-6957.

1 files changed, 8 insertions, 0 deletions

diff --git a/test/files/run/t6506.scala b/test/files/run/t6506.scala
new file mode 100644
index 0000000000..04d77c3c16
--- /dev/null
+++ b/test/files/run/t6506.scala
@@ -0,0 +1,8 @@
+object Test {
+  def main(args: Array[String]) {
+    new WL(new {} #:: S) with T
+  }
+  object S { def #::(a: Any): Any = () }
+  trait T
+  class WL(a: Any)
+}