Add error message for <> of Vec and Seq of different lengths (#739)

Fixes #482

2 files changed, 25 insertions, 1 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
index a4eeb8a5..b89961aa 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/Aggregate.scala
@@ -176,7 +176,9 @@ sealed class Vec[T <: Data] private[core] (gen: => T, val length: Int)
     * @note the length of this Vec must match the length of the input Seq
     */
   def <> (that: Seq[T])(implicit sourceInfo: SourceInfo, moduleCompileOptions: CompileOptions): Unit = {
-    require(this.length == that.length)
+    if (this.length != that.length) {
+      Builder.error("Vec and Seq being bulk connected have different lengths!")
+    }
     for ((a, b) <- this zip that)
       a <> b
   }
diff --git a/src/test/scala/chiselTests/Vec.scala b/src/test/scala/chiselTests/Vec.scala
index 1c5157b5..08b9cdf5 100644
--- a/src/test/scala/chiselTests/Vec.scala
+++ b/src/test/scala/chiselTests/Vec.scala
@@ -252,4 +252,26 @@ class VecSpec extends ChiselPropSpec {
   property("Dynamic indexing of a Vec of Module IOs should work") {
     assertTesterPasses{ new ModuleIODynamicIndexTester(4) }
   }
+
+  property("It should be possible to bulk connect a Vec and a Seq") {
+    elaborate(new Module {
+      val io = IO(new Bundle {
+        val out = Output(Vec(4, UInt(8.W)))
+      })
+      val seq = Seq.fill(4)(0.U)
+      io.out <> seq
+    })
+  }
+
+  property("Bulk connecting a Vec and Seq of different sizes should report a ChiselException") {
+    a [ChiselException] should be thrownBy {
+      elaborate(new Module {
+        val io = IO(new Bundle {
+          val out = Output(Vec(4, UInt(8.W)))
+        })
+        val seq = Seq.fill(5)(0.U)
+        io.out <> seq
+      })
+    }
+  }
 }