Replacematcherror - catch exceptions and convert to internal error. (#424)

* Catch exceptions and convert to internal error.
We need to update the displayed message to incorporate a line number and text to be used for the issue.

* Cleanup exception handling/throwing.
Re-throw expected (or uncorrectable exceptions).
Provide Utils.getThrowable() to get the first (eldest) or last throwable in the chain.
Update tests to conform to FreeSpec protocol.

* Minor cleanup
Admit we've updated some deprecated ScalaTest methods.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/main/scala/firrtl/Compiler.scala b/src/main/scala/firrtl/Compiler.scala
index 43596765..504ec85c 100644
--- a/src/main/scala/firrtl/Compiler.scala
+++ b/src/main/scala/firrtl/Compiler.scala
@@ -203,7 +203,7 @@ final case object LowForm extends CircuitForm(0)
   * this requirement.
   */
 final case object UnknownForm extends CircuitForm(-1) {
-  override def compare(that: CircuitForm): Int = { error("Illegal to compare UnknownForm"); 0 }
+  override def compare(that: CircuitForm): Int = { sys.error("Illegal to compare UnknownForm"); 0 }
 }
 
 /** The basic unit of operating on a Firrtl AST */
@@ -331,8 +331,8 @@ object CompilerUtils extends LazyLogging {
           Seq(new IRToWorkingIR, new ResolveAndCheck, new transforms.DedupModules,
               new HighFirrtlToMiddleFirrtl) ++ getLoweringTransforms(MidForm, outputForm)
         case MidForm => Seq(new MiddleFirrtlToLowFirrtl) ++ getLoweringTransforms(LowForm, outputForm)
-        case LowForm => throwInternalError // should be caught by if above
-        case UnknownForm => throwInternalError // should be caught by if above
+        case LowForm => throwInternalError(Some("getLoweringTransforms - LowForm")) // should be caught by if above
+        case UnknownForm => throwInternalError(Some("getLoweringTransforms - UnknownForm")) // should be caught by if above
       }
     }
   }