From 5d555ef90f443e20d2e46c668e456df0a643dae8 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Sat, 17 Mar 2012 21:12:51 -0700
Subject: Overhaul of JavaConver{sions,ters}.

Initially motivated by SI-5580, then just motivated.  I broke up
the opaquely named JavaConversions and JavaConverters into the following
traits encapsulating some permutation of

  { to java, to scala, bidirectional }
  { wrappers, decorators }

I named everything consistently in terms of either Wrappers
or Decorators.  Decorators install those asJava/asScala methods
onto collections of the right kind; Wrappers hide the process.

JavaConversions then reduces to an object which (ill-advisedly)
extends both WrapAsJava and WrapAsScala.  And JavaConverters is
an object extending DecorateAsScala and DecorateAsJava.  However
other more clearly named vals exist in the newly created
scala.collection.convert package object.

  val decorateAsJava  = new DecorateAsJava { }
  val decorateAsScala = new DecorateAsScala { }
  val decorateAll     = new DecorateAsJava with DecorateAsScala { }
  val wrapAsJava      = new WrapAsJava { }
  val wrapAsScala     = new WrapAsScala { }
  val wrapAll         = new WrapAsJava with WrapAsScala { }

So for instance to import asScala decorators, and only those:

  scala> import scala.collection.convert.decorateAsScala._
  import scala.collection.convert.decorateAsScala._

  scala> new java.util.ArrayList[String].asScala groupBy (x => x)
  res0: scala.collection.immutable.Map[String,scala.collection.mutable.Buffer[String]] = Map()

I propose we put those vals or a subset of them in the scala
package object rather than way down in scala.collection.convert.
---
 test/files/neg/saferJavaConversions.check |  6 ++++++
 test/files/neg/saferJavaConversions.scala | 20 ++++++++++++++++++++
 test/files/neg/t5580a.check               |  6 ++++++
 test/files/neg/t5580a.scala               | 11 +++++++++++
 4 files changed, 43 insertions(+)
 create mode 100644 test/files/neg/saferJavaConversions.check
 create mode 100644 test/files/neg/saferJavaConversions.scala
 create mode 100644 test/files/neg/t5580a.check
 create mode 100644 test/files/neg/t5580a.scala

(limited to 'test/files/neg')

diff --git a/test/files/neg/saferJavaConversions.check b/test/files/neg/saferJavaConversions.check
new file mode 100644
index 0000000000..0e53d2c437
--- /dev/null
+++ b/test/files/neg/saferJavaConversions.check
@@ -0,0 +1,6 @@
+saferJavaConversions.scala:13: error: type mismatch;
+ found   : String("a")
+ required: Foo
+    val v = map.get("a")  // now this is a type error
+                    ^
+one error found
diff --git a/test/files/neg/saferJavaConversions.scala b/test/files/neg/saferJavaConversions.scala
new file mode 100644
index 0000000000..f0611204e6
--- /dev/null
+++ b/test/files/neg/saferJavaConversions.scala
@@ -0,0 +1,20 @@
+
+case class Foo(s: String)
+
+object Test {
+  def f1 = {
+    import scala.collection.JavaConversions._
+    val map: Map[Foo, String] = Map(Foo("a") -> "a", Foo("b") -> "b")
+    val v = map.get("a")  // should be a type error, actually returns null
+  }
+  def f2 = {
+    import scala.collection.convert.wrapAsScala._
+    val map: Map[Foo, String] = Map(Foo("a") -> "a", Foo("b") -> "b")
+    val v = map.get("a")  // now this is a type error
+  }
+  def f3 = {
+    import scala.collection.convert.wrapAsJava._
+    val map: Map[Foo, String] = Map(Foo("a") -> "a", Foo("b") -> "b")
+    val v = map.get("a")
+  }
+}
diff --git a/test/files/neg/t5580a.check b/test/files/neg/t5580a.check
new file mode 100644
index 0000000000..50a31857d5
--- /dev/null
+++ b/test/files/neg/t5580a.check
@@ -0,0 +1,6 @@
+t5580a.scala:9: error: polymorphic expression cannot be instantiated to expected type;
+ found   : [A]scala.collection.mutable.Set[A]
+ required: scala.collection.mutable.Map[bar,scala.collection.mutable.Set[bar]]
+    if (map.get(tmp).isEmpty) map.put(tmp,collection.mutable.Set())
+                                                                ^
+one error found
diff --git a/test/files/neg/t5580a.scala b/test/files/neg/t5580a.scala
new file mode 100644
index 0000000000..742f0e85ea
--- /dev/null
+++ b/test/files/neg/t5580a.scala
@@ -0,0 +1,11 @@
+import scala.collection.mutable.WeakHashMap
+
+class bar{ }
+class foo{
+  val map = WeakHashMap[AnyRef, collection.mutable.Map[bar, collection.mutable.Set[bar]]]()
+
+  def test={
+    val tmp:bar=null
+    if (map.get(tmp).isEmpty) map.put(tmp,collection.mutable.Set())
+  }
+}
-- 
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