Fix use of global state in instance loop checking

Also increase sensitivity of thread safety checking
Fixes #159

1 files changed, 1 insertions, 1 deletions

diff --git a/src/main/scala/firrtl/passes/Checks.scala b/src/main/scala/firrtl/passes/Checks.scala
index 9bbf7fa8..ab6db202 100644
--- a/src/main/scala/firrtl/passes/Checks.scala
+++ b/src/main/scala/firrtl/passes/Checks.scala
@@ -256,7 +256,7 @@ object CheckHighForm extends Pass with LazyLogging {
             if (!c.modules.map(_.name).contains(s.module))
               errors.append(new ModuleNotDefinedException(s.module))
             // Check to see if a recursive module instantiation has occured
-            val childToParent = moduleGraph.add(mname, s.module)
+            val childToParent = moduleGraph.add(m.name, s.module)
             if(childToParent.nonEmpty) {
               errors.append(new InstanceLoop(childToParent.mkString("->")))
             }