catch None.get in BitPat.apply(x: UInt): BitPat (#2276)

Co-authored-by: Jack Koenig <koenig@sifive.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/main/scala/chisel3/util/BitPat.scala b/src/main/scala/chisel3/util/BitPat.scala
index d607be4f..4b94879f 100644
--- a/src/main/scala/chisel3/util/BitPat.scala
+++ b/src/main/scala/chisel3/util/BitPat.scala
@@ -89,6 +89,7 @@ object BitPat {
     * @note the UInt must be a literal
     */
   def apply(x: UInt): BitPat = {
+    require(x.isLit, s"$x is not a literal, BitPat.apply(x: UInt) only accepts literals")
     val len = if (x.isWidthKnown) x.getWidth else 0
     apply("b" + x.litValue.toString(2).reverse.padTo(len, "0").reverse.mkString)
   }