SI-9697 / SD-229 Fix DelayedInit subclass capturing local value

When a class captures an outer value, a field for that value is created
in the class. The class also gets a constructor parameter for the
captured value, the constructor will assign the field.

LambdaLift re-writes accesses to the local value (Ident trees) to the
field. However, if the statement accessing the local value will end up
inside the constructor, the access is re-written to the constructor
parameter instead. This is the case for constructor statements:

    class C {
      {
        println(capturedLocal)
      }
    }

If C extends DelayedInit, the statement does not end up in C's
constructor, but into a new synthetic method. The access to
`capturedLocal` needs to be re-written to the field instead of the
constructor parameter.

LambdaLift takes the decision (field or constructor parameter) based on
the owner chain of `currentOwner`. For the constructor statement block,
the owner is a local dummy, for which `logicallyEnclosingMember` returns
the constructor symbol.

This commit introduces a special case in LambdaLift for local dummies
of DelayedInit subclasses: instead of the constructor, we use a
temporary symbol representing the synthetic method holding the
initializer statements.

1 files changed, 127 insertions, 0 deletions

diff --git a/test/files/run/t9697.scala b/test/files/run/t9697.scala
new file mode 100644
index 0000000000..b837feb237
--- /dev/null
+++ b/test/files/run/t9697.scala
@@ -0,0 +1,127 @@
+object log {
+  val b = new collection.mutable.StringBuilder
+  def apply(s: Any): Unit = b.append(s)
+  def check(s: String) = {
+    val bs = b.toString
+    assert(s == bs, bs)
+    b.clear()
+  }
+}
+
+package t9697 {
+  abstract class WA extends DelayedInit {
+    override def delayedInit(x: => Unit): Unit = x
+    val waField = "4"
+  }
+
+  class C {
+    def b(s: String) = log(s)
+    val cField = "1"
+
+    {
+      val dummyLocal = "2"
+      new WA {
+        val anonField = "3"
+        b(cField)
+        b(dummyLocal)
+        b(anonField)
+        b(waField)
+      }
+    }
+  }
+}
+
+package sd229 {
+  class Broken {
+    def is(ee: AnyRef) = {
+      new Delayed {
+        log(ee)
+      }
+    }
+  }
+
+  class Delayed extends DelayedInit {
+    def delayedInit(x: => Unit): Unit = x
+  }
+}
+
+
+// already fixed in 2.11.8, crashes in 2.10.6
+package t4683a {
+  class A { log("a") }
+  class B { log("b") }
+  class Bug extends DelayedInit {
+    log("bug")
+    def foo(a: A): B = new B
+    def delayedInit(init: => Unit): Unit = init
+  }
+}
+
+// already fixed in 2.12.0-RC1, crashes in 2.11.8
+package t4683b {
+  class Entity extends DelayedInit {
+    def delayedInit(x: => Unit): Unit = x
+    
+    class Field
+    
+    protected def EntityField[T <: Entity: reflect.ClassTag] = new Field
+    
+    def find[T <: Entity: reflect.ClassTag] {
+      Nil.map(dbo => {
+        class EntityHolder extends Entity {
+          val entity = EntityField[T]
+        }
+      })
+      log("find")
+    }
+  }
+}
+
+package t4683c {
+  trait T extends DelayedInit {
+    def delayedInit(body: => Unit) = {
+      log("init")
+      body
+    }
+  }
+}
+
+package t4683d {
+  class C extends DelayedInit {
+    def delayedInit(body: => Unit): Unit = body
+  }
+  class Injector {
+    def test: Object = {
+      val name = "k"
+      class crash extends C {
+        log(name)
+      }
+      new crash()
+    }
+  }
+}
+
+object Test extends App {
+  new t9697.C()
+  log.check("1234")
+
+  new sd229.Broken().is("hi")
+  log.check("hi")
+
+  val a: t4683a.A = new t4683a.A
+  var b: t4683a.B = null
+  new t4683a.Bug {
+    val b = foo(a)
+  }
+  log.check("abugb")
+
+  new t4683b.Entity().find[t4683b.Entity]
+  log.check("find")
+
+  val f = (p1: Int) => new t4683c.T { log(p1) }
+  f(5)
+  log.check("init5")
+
+  new t4683d.Injector().test
+  log.check("k")
+}