SI-4425 do some validity checking on unapplies.

Filter out unapplies which can't be called (such as those with
a second non-implicit parameter list) and report the error in a
meaningful fashion.

3 files changed, 95 insertions, 1 deletions

diff --git a/test/files/neg/t4425.check b/test/files/neg/t4425.check
index 0f2fe6f2d1..cb5da6e7dc 100644
--- a/test/files/neg/t4425.check
+++ b/test/files/neg/t4425.check
@@ -1,4 +1,5 @@
-t4425.scala:3: error: isInstanceOf cannot test if value types are references.
+t4425.scala:3: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: Int)(y: Option[Int]): None.type exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
   42 match { case _ X _ => () }
                     ^
 one error found
diff --git a/test/files/neg/t4425b.check b/test/files/neg/t4425b.check
new file mode 100644
index 0000000000..e43c489586
--- /dev/null
+++ b/test/files/neg/t4425b.check
@@ -0,0 +1,55 @@
+t4425b.scala:5: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:6: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:7: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println(      "" match { case X(_)    => "ok" ; case _ => "fail" })
+                                  ^
+t4425b.scala:8: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println((X: Any) match { case X(_)    => "ok" ; case _ => "fail" })
+                                  ^
+t4425b.scala:9: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+                                  ^
+t4425b.scala:10: error: object X is not a case class constructor, nor does it have an unapply/unapplySeq method
+Note: def unapply(x: String)(y: String): Nothing exists in object X, but it cannot be used as an extractor due to its second non-implicit parameter list
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+                                  ^
+t4425b.scala:18: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:19: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:20: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println(      "" match { case X(_)    => "ok" ; case _ => "fail" })
+                                   ^
+t4425b.scala:21: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println((X: Any) match { case X(_)    => "ok" ; case _ => "fail" })
+                                   ^
+t4425b.scala:22: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+                                   ^
+t4425b.scala:23: error: result type Nothing of unapply defined in method unapply in object X does not conform to Option[_] or Boolean
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+                                   ^
+t4425b.scala:31: error: wrong number of arguments for object X
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:32: error: wrong number of arguments for object X
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+                                    ^
+t4425b.scala:35: error: wrong number of arguments for object X
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+                                   ^
+t4425b.scala:36: error: wrong number of arguments for object X
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+                                   ^
+16 errors found
diff --git a/test/files/neg/t4425b.scala b/test/files/neg/t4425b.scala
new file mode 100644
index 0000000000..861e9521f6
--- /dev/null
+++ b/test/files/neg/t4425b.scala
@@ -0,0 +1,38 @@
+object Test1 {
+  object X { def unapply(x : String)(y: String) = throw new Exception }
+
+  def f1() {
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_)    => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_)    => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+  }
+}
+
+object Test2 {
+  object X { def unapply(x : String) = throw new Exception }
+
+  def f1() {
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_)    => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_)    => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+  }
+}
+
+object Test3 {
+  object X { def unapply(x : String) = None }
+
+  def f1() {
+    println(      "" match { case _ X _   => "ok" ; case _ => "fail" })
+    println((X: Any) match { case _ X _   => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_)    => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_)    => "ok" ; case _ => "fail" })
+    println(      "" match { case X(_, _) => "ok" ; case _ => "fail" })
+    println((X: Any) match { case X(_, _) => "ok" ; case _ => "fail" })
+  }
+}