diff --git a/.gitignore b/.gitignore
index b4fc65d..9cc0d18 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ generated/
 .idea
 target/
 *.iml
+*.swp
diff --git a/chiselFrontend/src/main/scala/chisel3/core/.Data.scala.swp b/chiselFrontend/src/main/scala/chisel3/core/.Data.scala.swp
deleted file mode 100644
index 493ab02..0000000
Binary files a/chiselFrontend/src/main/scala/chisel3/core/.Data.scala.swp and /dev/null differ
diff --git a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
index 049e90a..1413fcd 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
@@ -265,7 +265,7 @@ sealed class Vec[T <: Data] private (gen: => T, val length: Int)
   }
 
   override def _onModuleClose: Unit = {
-    sample_element.setRef(this, 0)
+    sample_element.setRefBinder(this)
   }
 }
 
@@ -584,6 +584,7 @@ trait BitsLevelNamer {
     case ax: Index => argIsTemp(ax.imm) || strTmp(ax.name)
     case ax: Node => !ax.id.refSet || strTmp(ax.name)
     case ax: LitArg => false
+    case ax: BindIndex => argIsTemp(ax.imm)
   }
 
 
diff --git a/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala b/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
index b0b8913..5878d4e 100644
--- a/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
+++ b/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
@@ -106,6 +106,7 @@ private[chisel3] trait HasId extends InstanceId {
   private[chisel3] def setRef(parent: HasId, name: String): Unit = setRef(Slot(Node(parent), name))
   private[chisel3] def setRef(parent: HasId, index: Int): Unit = setRef(Index(Node(parent), ILit(index)))
   private[chisel3] def setRef(parent: HasId, index: UInt): Unit = setRef(Index(Node(parent), index.ref))
+  private[chisel3] def setRefBinder(parent: HasId): Unit = setRef(BindIndex(Node(parent)))
   // private[chisel3] def setRef(parent: HasId, names: Seq[String]): Unit = {
   //   var newRef = Node(parent)
   //   for(name <- names) {
diff --git a/chiselFrontend/src/main/scala/chisel3/internal/firrtl/IR.scala b/chiselFrontend/src/main/scala/chisel3/internal/firrtl/IR.scala
index 9446be0..47926bd 100644
--- a/chiselFrontend/src/main/scala/chisel3/internal/firrtl/IR.scala
+++ b/chiselFrontend/src/main/scala/chisel3/internal/firrtl/IR.scala
@@ -120,6 +120,11 @@ case class Index(imm: Arg, value: Arg) extends Arg {
   override def fullName(ctx: Component): String = s"${imm.fullName(ctx)}[${value.fullName(ctx)}]"
   def pprint = s"Index(${imm.name}, ${value.name})"
 }
+case class BindIndex(imm: Arg) extends Arg {
+  def name: String = s"[_]"
+  override def fullName(ctx: Component): String = s"${imm.fullName(ctx)}[_]"
+  def pprint = s"Index(${imm.name}, _)"
+}
 
 sealed trait Bound
 sealed trait NumericBound[T] extends Bound {
diff --git a/src/main/scala/chisel3/util/.Decoupled.scala.swp b/src/main/scala/chisel3/util/.Decoupled.scala.swp
deleted file mode 100644
index 68066bb..0000000
Binary files a/src/main/scala/chisel3/util/.Decoupled.scala.swp and /dev/null differ
diff --git a/src/main/scala/chisel3/util/Arbiter.scala b/src/main/scala/chisel3/util/Arbiter.scala
index 20d9c54..3cf7d26 100644
--- a/src/main/scala/chisel3/util/Arbiter.scala
+++ b/src/main/scala/chisel3/util/Arbiter.scala
@@ -24,7 +24,7 @@ class ArbiterIO[T <: Data](gen: T, out_gen: T, n: Int, inl: Label, outl: Label)
 
 /** Arbiter Control determining which producer has access
   */
-private object ArbiterCtrl {
+object ArbiterCtrl {
   def apply(request: Seq[Bool]): Seq[Bool] = request.length match {
     case 0 => Seq()
     case 1 => Seq(true.B)