Reject negative shift amounts; add tests (#730)

Closes #729

1 files changed, 9 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/UIntOps.scala b/src/test/scala/chiselTests/UIntOps.scala
index d31d86a8..490af22b 100644
--- a/src/test/scala/chiselTests/UIntOps.scala
+++ b/src/test/scala/chiselTests/UIntOps.scala
@@ -91,6 +91,11 @@ class BadBoolConversion extends Module {
   io.b := io.u.toBool
 }
 
+class NegativeShift(t: => Bits) extends Module {
+  val io = IO(new Bundle)
+  Reg(t) >> -1
+}
+
 class UIntOpsSpec extends ChiselPropSpec with Matchers {
   // Disable shrinking on error.
   implicit val noShrinkListVal = Shrink[List[Int]](_ => Stream.empty)
@@ -111,5 +116,9 @@ class UIntOpsSpec extends ChiselPropSpec with Matchers {
   property("UIntOpsTester should return the correct result") {
     assertTesterPasses { new UIntOpsTester(123, 7) }
   }
+
+  property("Negative shift amounts are invalid") {
+    a [ChiselException] should be thrownBy { elaborate(new NegativeShift(UInt())) }
+  }
 }