Support concatenating properties of Seq subtypes (#4907)

Author: debs-sifive

core/src/main/scala/chisel3/properties/Property.scala

@@ -454,9 +454,9 @@ object PropertySequenceOps {
   import PropertyExpressionHelpers._
 
   // Type class instances for Property sequence operations.
-  implicit def seqOps[U]: PropertySequenceOps[Property[Seq[U]]] =
-    new PropertySequenceOps[Property[Seq[U]]] {
-      def concat(lhs: Property[Seq[U]], rhs: Property[Seq[U]])(implicit sourceInfo: SourceInfo) =
+  implicit def seqOps[U, S[U] <: Seq[U]]: PropertySequenceOps[Property[S[U]]] =
+    new PropertySequenceOps[Property[S[U]]] {
+      def concat(lhs: Property[S[U]], rhs: Property[S[U]])(implicit sourceInfo: SourceInfo) =
         binOp(sourceInfo, fir.ListConcatOp, lhs, rhs)
     }
 }

src/test/scala-2/chiselTests/properties/PropertySpec.scala

@@ -360,6 +360,42 @@ class PropertySpec extends AnyFlatSpec with Matchers with FileCheck {
     )
   }
 
+  it should "support concatenation of Property[Seq[Int]]" in {
+    ChiselStage.emitCHIRRTL {
+      new RawModule {
+        val seqProp1 = IO(Input(Property[Seq[Int]]()))
+        val seqProp2 = IO(Input(Property[Seq[Int]]()))
+        val seqProp3 = IO(Output(Property[Seq[Int]]()))
+        seqProp3 := seqProp1 ++ seqProp2
+      }
+    }.fileCheck()(
+      """|CHECK: input seqProp1 : List<Integer>
+         |CHECK: input seqProp2 : List<Integer>
+         |CHECK: output seqProp3 : List<Integer>
+         |CHECK: wire _seqProp3_propExpr : List<Integer>
+         |CHECK: propassign _seqProp3_propExpr, list_concat(seqProp1, seqProp2)
+         |""".stripMargin
+    )
+  }
+
+  it should "support concatenation of Property[List[Int]]" in {
+    ChiselStage.emitCHIRRTL {
+      new RawModule {
+        val listProp1 = IO(Input(Property[List[Int]]()))
+        val listProp2 = IO(Input(Property[List[Int]]()))
+        val listProp3 = IO(Output(Property[List[Int]]()))
+        listProp3 := listProp1 ++ listProp2
+      }
+    }.fileCheck()(
+      """|CHECK: input listProp1 : List<Integer>
+         |CHECK: input listProp2 : List<Integer>
+         |CHECK: output listProp3 : List<Integer>
+         |CHECK: wire _listProp3_propExpr : List<Integer>
+         |CHECK: propassign _listProp3_propExpr, list_concat(listProp1, listProp2)
+         |""".stripMargin
+    )
+  }
+
   it should "not support types with nested Property[_]" in {
     assertTypeError("Property[Property[Property[Int]]]()")
     assertTypeError("Property[Property[Seq[Property[Int]]]]()")