SI-4842 Forbid access to in-construction this in self-constructor args

The check was already in place for direct calls to the super constructor.
Without this additional check, ExplicitOuter crashes, as it doesn't create
an $outer pointer for the constructor-arg scoped inner object, but expects
one to exist when transforming the Outer.this reference.

1 files changed, 3 insertions, 0 deletions

diff --git a/test/files/neg/t4842b.scala b/test/files/neg/t4842b.scala
new file mode 100644
index 0000000000..a7996cc061
--- /dev/null
+++ b/test/files/neg/t4842b.scala
@@ -0,0 +1,3 @@
+class TypeArg[X](val x: X)(a: AnyRef) {
+  def this() = { this(???)(new { println(TypeArg.this.x) } ); println("next") } // error
+}