Better typing of seqLiteral in erasure.

Fixed two problems with previous commit.

Author: odersky

src/dotty/tools/dotc/core/TypeApplications.scala

@@ -367,8 +367,11 @@ class TypeApplications(val self: Type) extends AnyVal {
   }
 
   /** The element type of a sequence or array */
-  def elemType(implicit ctx: Context): Type =
-    firstBaseArgInfo(defn.SeqClass) orElse firstBaseArgInfo(defn.ArrayClass)
+  def elemType(implicit ctx: Context): Type = self match {
+    case defn.ArrayType(elemtp) => elemtp
+    case JavaArrayType(elemtp) => elemtp
+    case _ => firstBaseArgInfo(defn.SeqClass)
+  }
 
   /** Given a type alias
    *

src/dotty/tools/dotc/transform/Erasure.scala

@@ -375,7 +375,7 @@ object Erasure extends TypeTestsCasts{
     }
 
     override def typedSeqLiteral(tree: untpd.SeqLiteral, pt: Type)(implicit ctx: Context) =
-      super.typedSeqLiteral(tree, tree.typeOpt)
+      super.typedSeqLiteral(tree, erasure(tree.typeOpt))
         // proto type of typed seq literal is original type; this makes elements be adapted to correct type.
 
     override def typedValDef(vdef: untpd.ValDef, sym: Symbol)(implicit ctx: Context): ValDef =