Convert PreservesAll to explicit invalidates=false

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/main/scala/firrtl/passes/ToWorkingIR.scala b/src/main/scala/firrtl/passes/ToWorkingIR.scala
index 7da94be8..c271302a 100644
--- a/src/main/scala/firrtl/passes/ToWorkingIR.scala
+++ b/src/main/scala/firrtl/passes/ToWorkingIR.scala
@@ -1,10 +1,10 @@
 package firrtl.passes
 
 import firrtl.ir._
-import firrtl.options.PreservesAll
 import firrtl.Transform
 
-object ToWorkingIR extends Pass with PreservesAll[Transform] {
+object ToWorkingIR extends Pass {
   override def prerequisites = firrtl.stage.Forms.MinimalHighForm
+  override def invalidates(a: Transform) = false
   def run(c:Circuit): Circuit = c
 }