From 1c56489b3e008ffb192443a1627df16f245a6c01 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Sat, 18 Jul 2009 15:19:55 +0000
Subject: Fix and post/neg test cases for #1878.

---
 src/compiler/scala/tools/nsc/ast/TreeInfo.scala       | 12 ++++++++++++
 src/compiler/scala/tools/nsc/typechecker/Typers.scala |  4 ++++
 test/files/neg/bug1878.check                          |  7 +++++++
 test/files/neg/bug1878.scala                          | 10 ++++++++++
 4 files changed, 33 insertions(+)
 create mode 100644 test/files/neg/bug1878.check
 create mode 100644 test/files/neg/bug1878.scala

diff --git a/src/compiler/scala/tools/nsc/ast/TreeInfo.scala b/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
index 3d023777f3..3eb6dc321b 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
@@ -276,6 +276,18 @@ abstract class TreeInfo {
     case _ => false
   }
 
+  /** The underlying pattern ignoring any bindings */
+  def unbind(x: Tree): Tree = x match {
+    case Bind(_, y) => unbind(y)
+    case y          => y
+  }
+
+  /** Is this tree a Star(_) after removing bindings? */
+  def isStar(x: Tree) = unbind(x) match {
+    case Star(_)  => true
+    case _        => false
+  }
+
   /** The method part of an application node
    */
   def methPart(tree: Tree): Tree = tree match {
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index b1ed6da208..c2d69637b1 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1607,6 +1607,10 @@ trait Typers { self: Analyzer =>
      *  @return       ...
      */
     def typedCase(cdef: CaseDef, pattpe: Type, pt: Type): CaseDef = {
+      // verify no _* except in last position
+      for (Apply(_, xs) <- cdef.pat ; x <- xs dropRight 1 ; if treeInfo isStar x)
+        error(x.pos, "_* may only come last")
+
       val pat1: Tree = typedPattern(cdef.pat, pattpe)
       val guard1: Tree = if (cdef.guard == EmptyTree) EmptyTree
                          else typed(cdef.guard, BooleanClass.tpe)
diff --git a/test/files/neg/bug1878.check b/test/files/neg/bug1878.check
new file mode 100644
index 0000000000..7b25a909a2
--- /dev/null
+++ b/test/files/neg/bug1878.check
@@ -0,0 +1,7 @@
+bug1878.scala:3: error: _* may only come last
+  val err1 = "" match { case Seq(f @ _*, ',') => f }
+                                 ^
+bug1878.scala:9: error: _* may only come last
+  val List(List(_*, arg2), _) = List(List(1,2,3), List(4,5,6))
+                 ^
+two errors found
diff --git a/test/files/neg/bug1878.scala b/test/files/neg/bug1878.scala
new file mode 100644
index 0000000000..ca76df082b
--- /dev/null
+++ b/test/files/neg/bug1878.scala
@@ -0,0 +1,10 @@
+object Test extends Application {
+  // illegal
+  val err1 = "" match { case Seq(f @ _*, ',') => f }
+
+  // no error
+  val List(List(arg1, _*), _) = List(List(1,2,3), List(4,5,6))
+
+  // illegal
+  val List(List(_*, arg2), _) = List(List(1,2,3), List(4,5,6))
+}
\ No newline at end of file
-- 
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