Print a better message on constant width failures

I'm getting this error and the message is awful.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/main/scala/Chisel/internal/firrtl/IR.scala b/src/main/scala/Chisel/internal/firrtl/IR.scala
index 60a38a08..d53807c6 100644
--- a/src/main/scala/Chisel/internal/firrtl/IR.scala
+++ b/src/main/scala/Chisel/internal/firrtl/IR.scala
@@ -57,7 +57,7 @@ abstract class LitArg(val num: BigInt, widthArg: Width) extends Arg {
 
   protected def minWidth: Int
   if (forcedWidth) {
-    require(widthArg.get >= minWidth)
+    require(widthArg.get >= minWidth, s"The literal value ${num} was elaborated with a specificed width of ${widthArg.get} bits, but at least ${minWidth} bits are required.")
   }
 }