Add checks for misuse or omission of Module()

Implemented by adding a Boolean to check for alternating invocations of object
Module.apply and the constructor of abstract class Module.
Fixes #192

1 files changed, 7 insertions, 0 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala b/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
index b4b0e028..028ce628 100644
--- a/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
+++ b/chiselFrontend/src/main/scala/chisel3/internal/Builder.scala
@@ -146,6 +146,9 @@ private[chisel3] class DynamicContext() {
   val globalNamespace = new Namespace(None, Set())
   val components = ArrayBuffer[Component]()
   var currentModule: Option[Module] = None
+  // Set by object Module.apply before calling class Module constructor
+  // Used to distinguish between no Module() wrapping, multiple wrappings, and rewrapping
+  var readyForModuleConstr: Boolean = false
   val errors = new ErrorLog
 }
 
@@ -170,6 +173,10 @@ private[chisel3] object Builder {
       // A bare api call is, e.g. calling Wire() from the scala console).
     )
   }
+  def readyForModuleConstr: Boolean = dynamicContext.readyForModuleConstr
+  def readyForModuleConstr_=(target: Boolean): Unit = {
+    dynamicContext.readyForModuleConstr = target
+  }
 
   // TODO(twigg): Ideally, binding checks and new bindings would all occur here
   // However, rest of frontend can't support this yet.