3 files changed, 55 insertions, 32 deletions

diff --git a/src/dotty/tools/dotc/ast/Desugar.scala b/src/dotty/tools/dotc/ast/Desugar.scala
index b82bd47f6..335d0d66a 100644
--- a/src/dotty/tools/dotc/ast/Desugar.scala
+++ b/src/dotty/tools/dotc/ast/Desugar.scala
@@ -735,36 +735,59 @@ object desugar {
     }
   }
 
-  /** Traverse pattern and collect all variable names with their types in buffer.
-   *  Works for expanded as well as unexpanded patterns
-   */
-  private object getVars extends UntypedTreeAccumulator[ListBuffer[VarInfo]] {
-    override def apply(buf: ListBuffer[VarInfo], tree: Tree): ListBuffer[VarInfo] = {
-      def seenName(name: Name) = buf exists (_._1.name == name)
-      def add(named: NameTree, t: Tree): ListBuffer[VarInfo] =
-        if (seenName(named.name)) buf else buf += ((named, t))
-      tree match {
-        case Bind(nme.WILDCARD, _) =>
-          foldOver(buf, tree)
-        case tree @ Bind(_, Typed(tree1, tpt)) if !mayBeTypePat(tpt) =>
-          apply(add(tree, tpt), tree1)
-        case tree @ Bind(_, tree1) =>
-          apply(add(tree, TypeTree()), tree1)
-        case Typed(id: Ident, t) if isVarPattern(id) && id.name != nme.WILDCARD =>
-          add(id, t)
-        case id: Ident if isVarPattern(id) && id.name != nme.WILDCARD =>
-          add(id, TypeTree())
-        case _ =>
-          foldOver(buf, tree)
-      }
-    }
-  }
-
   /** Returns list of all pattern variables, possibly with their types,
    *  without duplicates
    */
-  private def getVariables(tree: Tree): List[VarInfo] =
-    getVars(new ListBuffer[VarInfo], tree).toList
+  private def getVariables(tree: Tree)(implicit ctx: Context): List[VarInfo] = {
+    val buf = new ListBuffer[VarInfo]
+    def seenName(name: Name) = buf exists (_._1.name == name)
+    def add(named: NameTree, t: Tree): Unit =
+      if (!seenName(named.name)) buf += ((named, t))
+    def collect(tree: Tree): Unit = tree match {
+      case Bind(nme.WILDCARD, _) =>
+        collect(tree)
+      case tree @ Bind(_, Typed(tree1, tpt)) if !mayBeTypePat(tpt) =>
+        add(tree, tpt)
+        collect(tree1)
+      case tree @ Bind(_, tree1) =>
+        add(tree, TypeTree())
+        collect(tree1)
+      case Typed(id: Ident, t) if isVarPattern(id) && id.name != nme.WILDCARD =>
+        add(id, t)
+      case id: Ident if isVarPattern(id) && id.name != nme.WILDCARD =>
+        add(id, TypeTree())
+      case Apply(_, args) =>
+        args foreach collect
+      case Pair(left, right) =>
+        collect(left)
+        collect(right)
+      case Typed(expr, _) =>
+        collect(expr)
+      case NamedArg(_, arg) =>
+        collect(arg)
+      case SeqLiteral(elems) =>
+        elems foreach collect
+      case Alternative(trees) =>
+        for (tree <- trees; (vble, _) <- getVariables(tree))
+          ctx.error("illegal variable in pattern alternative", vble.pos)
+      case Annotated(annot, arg) =>
+        collect(arg)
+      case InterpolatedString(_, _, elems) =>
+        elems foreach collect
+      case InfixOp(left, _, right) =>
+        collect(left)
+        collect(right)
+      case PrefixOp(_, od) =>
+        collect(od)
+      case Parens(tree) =>
+        collect(tree)
+      case Tuple(trees) =>
+        trees foreach collect
+      case _ =>
+    }
+    collect(tree)
+    buf.toList
+  }
 
   private class IrrefutableGenFrom(pat: Tree, expr: Tree) extends GenFrom(pat, expr)
 }
diff --git a/src/dotty/tools/dotc/util/ShowPickled.scala b/src/dotty/tools/dotc/util/ShowPickled.scala
index ab2801127..71c48042c 100644
--- a/src/dotty/tools/dotc/util/ShowPickled.scala
+++ b/src/dotty/tools/dotc/util/ShowPickled.scala
@@ -112,7 +112,7 @@ object ShowPickled {
     result.toInt
   }
 
-  def printFile(buf: PickleBuffer, out: PrintStream = System.out) {
+  def printFile(buf: PickleBuffer, out: PrintStream = System.out): Unit = {
     out.println("Version " + buf.readNat() + "." + buf.readNat())
     val index = buf.createIndex
     val entryList = makeEntryList(buf, index)
@@ -120,7 +120,7 @@ object ShowPickled {
 
     def p(s: String) = out print s
 
-    def printNameRef() {
+    def printNameRef(): Unit = {
       val idx = buf.readNat()
       val name = entryList nameAt idx
       val toPrint = " %s(%s)".format(idx, name)
@@ -138,7 +138,7 @@ object ShowPickled {
     def printConstAnnotArgRef() = printNat()
     def printAnnotArgRef() = printNat()
 
-    def printSymInfo(end: Int) {
+    def printSymInfo(end: Int): Unit = {
       printNameRef()
       printSymbolRef()
       val pflags = buf.readLongNat()
@@ -176,7 +176,7 @@ object ShowPickled {
      *  interpreted are for the most part going to tell you the wrong thing.
      *  It's not so easy to duplicate the logic applied in the UnPickler.
      */
-    def printEntry(i: Int) {
+    def printEntry(i: Int): Unit = {
       buf.readIndex = index(i)
       p(i + "," + buf.readIndex + ": ")
       val tag = buf.readByte()
diff --git a/src/dotty/tools/dotc/util/Stats.scala b/src/dotty/tools/dotc/util/Stats.scala
index 3aa6eb9b9..3d7628477 100644
--- a/src/dotty/tools/dotc/util/Stats.scala
+++ b/src/dotty/tools/dotc/util/Stats.scala
@@ -30,7 +30,7 @@ object Stats {
         print("|")
     }
 
-    override final def run() {
+    override final def run(): Unit = {
       Thread.sleep(HeartBeatPeriod)
       printStack(stack)
       if (continue) run()