Use a mix-in to override Seq error

3 files changed, 21 insertions, 7 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
index cfb9810c..4ffbb893 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
@@ -479,6 +479,21 @@ abstract class Record(private[chisel3] implicit val compileOptions: CompileOptio
   def toPrintable: Printable = toPrintableHelper(elements.toList)
 }
 
+/**
+  * Mix-in for Bundles that have arbitrary Seqs of Chisel types that aren't
+  * involved in hardware construction.
+  *
+  * Used to avoid raising an error/exception when a Seq is a public member of the
+  * bundle.
+  * This is useful if we those public Seq fields in the Bundle are unrelated to
+  * hardware construction.
+  */
+trait IgnoreSeqInBundle {
+  this: Bundle =>
+
+  override def ignoreSeq: Boolean = true
+}
+
 class AutoClonetypeException(message: String) extends ChiselException(message, null)
 
 /** Base class for data types defined as a bundle of other data types.
@@ -555,8 +570,8 @@ abstract class Bundle(implicit compileOptions: CompileOptions) extends Record {
                 case d: Data => throwException("Public Seq members cannot be used to define Bundle elements " +
                   s"(found public Seq member '${m.getName}'). " +
                   "Either use a Vec() if all elements are of the same type, or HeterogeneousVec() if the elements " +
-                  "are of different types. If this Seq member is not intended to construct RTL, override ignoreSeq " +
-                  "to be true.")
+                  "are of different types. If this Seq member is not intended to construct RTL, mix in the trait " +
+                  "IgnoreSeqInBundle.")
                 case _ => // don't care about non-Data Seq
               }
               case _ => // not a Seq
@@ -568,8 +583,7 @@ abstract class Bundle(implicit compileOptions: CompileOptions) extends Record {
   }
 
   /**
-    * Override this to be true to avoid raising an error/exception when a Seq is a public member of the bundle.
-    * This is useful if you have public Seq fields in the Bundle that are unrelated to hardware construction.
+    * Overridden by [[IgnoreSeqInBundle]] to allow arbitrary Seqs of Chisel elements.
     */
   def ignoreSeq: Boolean = false
 
diff --git a/src/main/scala/chisel3/package.scala b/src/main/scala/chisel3/package.scala
index 81056483..f0542d7e 100644
--- a/src/main/scala/chisel3/package.scala
+++ b/src/main/scala/chisel3/package.scala
@@ -119,6 +119,7 @@ package object chisel3 {    // scalastyle:ignore package.object.name
   type Vec[T <: Data] = chisel3.core.Vec[T]
   type VecLike[T <: Data] = chisel3.core.VecLike[T]
   type Bundle = chisel3.core.Bundle
+  type IgnoreSeqInBundle = chisel3.core.IgnoreSeqInBundle
   type Record = chisel3.core.Record
 
   val assert = chisel3.core.assert
diff --git a/src/test/scala/chiselTests/BundleSpec.scala b/src/test/scala/chiselTests/BundleSpec.scala
index b248f7b5..502134b4 100644
--- a/src/test/scala/chiselTests/BundleSpec.scala
+++ b/src/test/scala/chiselTests/BundleSpec.scala
@@ -3,6 +3,7 @@
 package chiselTests
 
 import chisel3._
+import chisel3.core.IgnoreSeqInBundle
 import chisel3.testers.BasicTester
 
 trait BundleSpecUtils {
@@ -91,9 +92,7 @@ class BundleSpec extends ChiselFlatSpec with BundleSpecUtils {
       new BasicTester {
         val m = Module(new Module {
           val io = IO(new Bundle {
-            val b = new BadSeqBundle {
-              override def ignoreSeq = true
-            }
+            val b = new BadSeqBundle with IgnoreSeqInBundle
           })
         })
         stop()