Overhauled sequence length logic in the pattern...

Overhauled sequence length logic in the pattern matcher. Removes
unnecessary boxing and a few varieties of wrongness.

Closes #3395, #3150, #2958, #2945, #2187. No review.

8 files changed, 115 insertions, 0 deletions

diff --git a/test/files/pos/bug2187-2.scala b/test/files/pos/bug2187-2.scala
new file mode 100644
index 0000000000..3f2742dd89
--- /dev/null
+++ b/test/files/pos/bug2187-2.scala
@@ -0,0 +1,7 @@
+class Test {
+  def test[A](list: List[A]) = list match {
+    case Seq(x, y) => "xy"
+    case Seq(x) => "x"
+    case _ => "something else"
+  }
+}
\ No newline at end of file
diff --git a/test/files/pos/bug2945.scala b/test/files/pos/bug2945.scala
new file mode 100644
index 0000000000..762bdb61e1
--- /dev/null
+++ b/test/files/pos/bug2945.scala
@@ -0,0 +1,12 @@
+object Foo {
+  def test(s: String) = {
+    (s: Seq[Char]) match {
+        case Seq('f', 'o', 'o', ' ', rest1 @ _*) =>
+          rest1
+        case Seq('b', 'a', 'r', ' ', ' ', rest2 @ _*) =>
+          rest2
+        case _ =>
+          s
+    }
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/bug2958.scala b/test/files/run/bug2958.scala
new file mode 100644
index 0000000000..dcd24ecc36
--- /dev/null
+++ b/test/files/run/bug2958.scala
@@ -0,0 +1,16 @@
+object Test {
+  def f(args: Array[String]) = args match {
+    case Array("-p", prefix, from, to) =>
+      prefix + from + to
+
+    case Array(from, to) =>
+      from + to
+
+    case _ =>
+      "default"
+  }
+
+  def main(args: Array[String]) {
+    assert(f(Array("1", "2")) == "12")
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/bug3150.scala b/test/files/run/bug3150.scala
new file mode 100644
index 0000000000..034703b5f7
--- /dev/null
+++ b/test/files/run/bug3150.scala
@@ -0,0 +1,10 @@
+object Test {
+  case object Bob { override def equals(other: Any) = true }
+  def f(x: Any) = x match { case Bob => Bob }
+
+  def main(args: Array[String]): Unit = {
+    assert(f(Bob) eq Bob)
+    assert(f(0) eq Bob)
+    assert(f(Nil) eq Bob)
+  }
+}
diff --git a/test/files/run/bug3395.check b/test/files/run/bug3395.check
new file mode 100644
index 0000000000..5f5521fae2
--- /dev/null
+++ b/test/files/run/bug3395.check
@@ -0,0 +1,2 @@
+abc
+def
diff --git a/test/files/run/bug3395.scala b/test/files/run/bug3395.scala
new file mode 100644
index 0000000000..b4990a1716
--- /dev/null
+++ b/test/files/run/bug3395.scala
@@ -0,0 +1,13 @@
+object Test {
+  def main(args: Array[String]): Unit = {
+    Seq("") match {
+      case Seq("")      => println("abc")
+      case Seq(_, _, x) => println(x)
+    }
+
+    Seq(1, 2, "def") match {
+      case Seq("")      => println("abc")
+      case Seq(_, _, x) => println(x)
+    }
+  }
+}
\ No newline at end of file
diff --git a/test/files/run/patmat-seqs.check b/test/files/run/patmat-seqs.check
new file mode 100644
index 0000000000..bb2a5ee44a
--- /dev/null
+++ b/test/files/run/patmat-seqs.check
@@ -0,0 +1,13 @@
+s3
+s2
+s1
+s0
+ss6
+d
+s3
+s3
+d
+s1
+s3
+d
+d
diff --git a/test/files/run/patmat-seqs.scala b/test/files/run/patmat-seqs.scala
new file mode 100644
index 0000000000..b5c47b4b4b
--- /dev/null
+++ b/test/files/run/patmat-seqs.scala
@@ -0,0 +1,42 @@
+object Test {
+  def f1(x: Any) = x match {
+    case Seq(1, 2, 3) => "s3"
+    case Seq(4, 5) => "s2"
+    case Seq(7) => "s1"
+    case Nil => "s0"
+    case Seq(_, _, _, _, _, x: String) => "ss6"
+    case _ => "d"
+  }
+
+  def f2(x: Any) = x match {
+    case Seq("a", "b", _*)  => "s2"
+    case Seq(1, _*)         => "s1"
+    case Seq(5, 6, 7, _*)   => "s3"
+    case _                  => "d"
+  }
+
+  def main(args: Array[String]): Unit = {
+    val xs1 = List(
+      List(1,2,3),
+      List(4,5),
+      Vector(7),
+      Seq(),
+      Seq(1, 2, 3, 4, 5, "abcd"),
+      "abc"
+    ) map f1
+
+    xs1 foreach println
+
+    val xs2 = List(
+      Seq(5, 6, 7),
+      Seq(5, 6, 7, 8, 9),
+      Seq("a"),
+      Seq(1, 6, 7),
+      List(5, 6, 7),
+      Nil,
+      5
+    ) map f2
+
+    xs2 foreach println
+  }
+}