Remove Data.setRef assertion (#1654)

It causes issues for some legal (if awkward) patterns. A larger refactor
of when refs are set could reinstate this check.

2 files changed, 3 insertions, 4 deletions

diff --git a/core/src/main/scala/chisel3/BlackBox.scala b/core/src/main/scala/chisel3/BlackBox.scala
index 1b093ee1..8f831044 100644
--- a/core/src/main/scala/chisel3/BlackBox.scala
+++ b/core/src/main/scala/chisel3/BlackBox.scala
@@ -165,8 +165,8 @@ abstract class BlackBox(val params: Map[String, Param] = Map.empty[String, Param
     // Long term solution will be to define BlackBox IO differently as part of
     //   it not descending from the (current) Module
     for ((name, port) <- namedPorts) {
-      // We have to force override the _ref because it was set during IO binding
-      port.setRef(ModuleIO(this, _namespace.name(name)), force = true)
+      // Override the _ref because it was set during IO binding
+      port.setRef(ModuleIO(this, _namespace.name(name)))
     }
 
     // We need to call forceName and onModuleClose on all of the sub-elements
diff --git a/core/src/main/scala/chisel3/internal/Builder.scala b/core/src/main/scala/chisel3/internal/Builder.scala
index 30fa2db2..57a0f968 100644
--- a/core/src/main/scala/chisel3/internal/Builder.scala
+++ b/core/src/main/scala/chisel3/internal/Builder.scala
@@ -198,8 +198,7 @@ private[chisel3] trait HasId extends InstanceId {
     }
 
   private var _ref: Option[Arg] = None
-  private[chisel3] def setRef(imm: Arg, force: Boolean = false): Unit = {
-    assert(force || _ref.isEmpty, s"Internal Error, setRef for $this called twice! first ${_ref.get}, second $imm")
+  private[chisel3] def setRef(imm: Arg): Unit = {
     _ref = Some(imm)
   }
   private[chisel3] def setRef(parent: HasId, name: String): Unit = setRef(Slot(Node(parent), name))