16 files changed, 61 insertions, 25 deletions
diff --git a/src/main/scala/Chisel/Aggregate.scala b/src/main/scala/Chisel/Aggregate.scala
index 8a0f20af..1506833c 100644
--- a/src/main/scala/Chisel/Aggregate.scala
+++ b/src/main/scala/Chisel/Aggregate.scala
@@ -1,9 +1,13 @@
 // See LICENSE for license details.
 
 package Chisel
+
 import scala.collection.immutable.ListMap
 import scala.collection.mutable.{ArrayBuffer, HashSet, LinkedHashMap}
-import Builder.pushCommand
+
+import internal._
+import internal.Builder.pushCommand
+import firrtl._
 
 /** An abstract class for data types that solely consist of (are an aggregate
   * of) other Data objects.
diff --git a/src/main/scala/Chisel/BitPat.scala b/src/main/scala/Chisel/BitPat.scala
index d7b01ba6..b4138992 100644
--- a/src/main/scala/Chisel/BitPat.scala
+++ b/src/main/scala/Chisel/BitPat.scala
@@ -21,7 +21,7 @@ object BitPat {
     var mask = BigInt(0)
     for (d <- x.tail) {
       if (d != '_') {
-        if (!"01?".contains(d)) Builder.error({"Literal: " + x + " contains illegal character: " + d})
+        require("01?".contains(d), "Literal: " + x + " contains illegal character: " + d)
         mask = (mask << 1) + (if (d == '?') 0 else 1)
         bits = (bits << 1) + (if (d == '1') 1 else 0)
       }
diff --git a/src/main/scala/Chisel/Bits.scala b/src/main/scala/Chisel/Bits.scala
index 41f13c48..b6ee6d1a 100644
--- a/src/main/scala/Chisel/Bits.scala
+++ b/src/main/scala/Chisel/Bits.scala
@@ -1,8 +1,11 @@
 // See LICENSE for license details.
 
 package Chisel
-import Builder.pushOp
-import PrimOp._
+
+import internal._
+import internal.Builder.pushOp
+import firrtl._
+import firrtl.PrimOp._
 
 /** Element is a leaf data type: it cannot contain other Data objects. Example
   * uses are for representing primitive data types, like integers and bits.
diff --git a/src/main/scala/Chisel/Data.scala b/src/main/scala/Chisel/Data.scala
index 679b8eb8..f9b277e1 100644
--- a/src/main/scala/Chisel/Data.scala
+++ b/src/main/scala/Chisel/Data.scala
@@ -1,7 +1,10 @@
 // See LICENSE for license details.
 
 package Chisel
-import Builder.pushCommand
+
+import internal._
+import internal.Builder.pushCommand
+import firrtl._
 
 sealed abstract class Direction(name: String) {
   override def toString: String = name
diff --git a/src/main/scala/Chisel/Driver.scala b/src/main/scala/Chisel/Driver.scala
index dd78ab8d..a31786d9 100644
--- a/src/main/scala/Chisel/Driver.scala
+++ b/src/main/scala/Chisel/Driver.scala
@@ -5,6 +5,9 @@ package Chisel
 import scala.sys.process._
 import java.io._
 
+import internal._
+import firrtl._
+
 trait FileSystemUtilities {
   def writeTempFile(pre: String, post: String, contents: String): File = {
     val t = File.createTempFile(pre, post)
diff --git a/src/main/scala/Chisel/Mem.scala b/src/main/scala/Chisel/Mem.scala
index f4003c25..bd27a9c7 100644
--- a/src/main/scala/Chisel/Mem.scala
+++ b/src/main/scala/Chisel/Mem.scala
@@ -1,7 +1,10 @@
 // See LICENSE for license details.
 
 package Chisel
-import Builder.pushCommand
+
+import internal._
+import internal.Builder.pushCommand
+import firrtl._
 
 object Mem {
   @deprecated("Mem argument order should be size, t; this will be removed by the official release", "chisel3")
diff --git a/src/main/scala/Chisel/Module.scala b/src/main/scala/Chisel/Module.scala
index f799a7ce..4284bbc4 100644
--- a/src/main/scala/Chisel/Module.scala
+++ b/src/main/scala/Chisel/Module.scala
@@ -1,9 +1,13 @@
 // See LICENSE for license details.
 
 package Chisel
+
 import scala.collection.mutable.{ArrayBuffer, HashSet}
-import Builder.pushCommand
-import Builder.dynamicContext
+
+import internal._
+import internal.Builder.pushCommand
+import internal.Builder.dynamicContext
+import firrtl._
 
 object Module {
   /** A wrapper method that all Module instantiations must be wrapped in
diff --git a/src/main/scala/Chisel/Reg.scala b/src/main/scala/Chisel/Reg.scala
index 098f3922..21415362 100644
--- a/src/main/scala/Chisel/Reg.scala
+++ b/src/main/scala/Chisel/Reg.scala
@@ -1,7 +1,10 @@
 // See LICENSE for license details.
 
 package Chisel
-import Builder.pushCommand
+
+import internal._
+import internal.Builder.pushCommand
+import firrtl._
 
 object Reg {
   private[Chisel] def makeType[T <: Data](t: T = null, next: T = null, init: T = null): T = {
diff --git a/src/main/scala/Chisel/When.scala b/src/main/scala/Chisel/When.scala
index a051e52c..7b8d60c2 100644
--- a/src/main/scala/Chisel/When.scala
+++ b/src/main/scala/Chisel/When.scala
@@ -1,7 +1,10 @@
 // See LICENSE for license details.
 
 package Chisel
-import Builder.pushCommand
+
+import internal._
+import internal.Builder.pushCommand
+import firrtl._
 
 object when {  // scalastyle:ignore object.name
   /** Create a `when` condition block, where whether a block of logic is
diff --git a/src/main/scala/Chisel/ir/Emitter.scala b/src/main/scala/Chisel/firrtl/Emitter.scala
index b4689d61..bcc566c5 100644
--- a/src/main/scala/Chisel/ir/Emitter.scala
+++ b/src/main/scala/Chisel/firrtl/Emitter.scala
@@ -1,6 +1,7 @@
 // See LICENSE for license details.
 
-package Chisel
+package Chisel.firrtl
+import Chisel._
 
 private class Emitter(circuit: Circuit) {
   override def toString: String = res.toString
diff --git a/src/main/scala/Chisel/ir/IR.scala b/src/main/scala/Chisel/firrtl/IR.scala
index 106ad20c..458e6ac5 100644
--- a/src/main/scala/Chisel/ir/IR.scala
+++ b/src/main/scala/Chisel/firrtl/IR.scala
@@ -1,6 +1,8 @@
 // See LICENSE for license details.
 
-package Chisel
+package Chisel.firrtl
+import Chisel._
+import Chisel.internal._
 
 case class PrimOp(val name: String) {
   override def toString: String = name
diff --git a/src/main/scala/Chisel/internal/Builder.scala b/src/main/scala/Chisel/internal/Builder.scala
index 79d5d6aa..385e25a2 100644
--- a/src/main/scala/Chisel/internal/Builder.scala
+++ b/src/main/scala/Chisel/internal/Builder.scala
@@ -1,10 +1,14 @@
 // See LICENSE for license details.
 
-package Chisel
+package Chisel.internal
+
 import scala.util.DynamicVariable
 import scala.collection.mutable.{ArrayBuffer, HashMap}
 
-private class Namespace(parent: Option[Namespace], keywords: Set[String]) {
+import Chisel._
+import Chisel.firrtl._
+
+private[Chisel] class Namespace(parent: Option[Namespace], keywords: Set[String]) {
   private var i = 0L
   private val names = collection.mutable.HashSet[String]()
 
@@ -28,7 +32,7 @@ private class Namespace(parent: Option[Namespace], keywords: Set[String]) {
   def child: Namespace = child(Set())
 }
 
-private class IdGen {
+private[Chisel] class IdGen {
   private var counter = -1L
   def next: Long = {
     counter += 1
@@ -68,7 +72,7 @@ class RefMap {
   def apply(id: HasId): Arg = _refmap(id._id)
 }
 
-private class DynamicContext {
+private[Chisel] class DynamicContext {
   val idGen = new IdGen
   val globalNamespace = new Namespace(None, Set())
   val globalRefMap = new RefMap
@@ -77,7 +81,7 @@ private class DynamicContext {
   val errors = new ErrorLog
 }
 
-private object Builder {
+private[Chisel] object Builder {
   // All global mutable state must be referenced via dynamicContextVar!!
   private val dynamicContextVar = new DynamicVariable[Option[DynamicContext]](None)
 
diff --git a/src/main/scala/Chisel/internal/Error.scala b/src/main/scala/Chisel/internal/Error.scala
index 4bfcb555..6c4c0880 100644
--- a/src/main/scala/Chisel/internal/Error.scala
+++ b/src/main/scala/Chisel/internal/Error.scala
@@ -1,17 +1,20 @@
 // See LICENSE for license details.
 
-package Chisel
+package Chisel.internal
+
 import scala.collection.mutable.ArrayBuffer
 
+import Chisel._
+
 class ChiselException(message: String, cause: Throwable) extends Exception(message, cause)
 
-private object throwException {
+private[Chisel] object throwException {
   def apply(s: String, t: Throwable = null): Nothing =
     throw new ChiselException(s, t)
 }
 
 /** Records and reports runtime errors and warnings. */
-private class ErrorLog {
+private[Chisel] class ErrorLog {
   def hasErrors: Boolean = errors.exists(_.isFatal)
 
   /** Log an error message */
diff --git a/src/main/scala/Chisel/util/Conditional.scala b/src/main/scala/Chisel/util/Conditional.scala
index b0ac4491..9cab25ef 100644
--- a/src/main/scala/Chisel/util/Conditional.scala
+++ b/src/main/scala/Chisel/util/Conditional.scala
@@ -31,15 +31,15 @@ class SwitchContext[T <: Bits](cond: T) {
 object is {   // scalastyle:ignore object.name
   // Begin deprecation of non-type-parameterized is statements.
   def apply(v: Iterable[Bits])(block: => Unit) {
-    Builder.error("The 'is' keyword may not be used outside of a switch.")
+    require(false, "The 'is' keyword may not be used outside of a switch.")
   }
 
   def apply(v: Bits)(block: => Unit) {
-    Builder.error("The 'is' keyword may not be used outside of a switch.")
+    require(false, "The 'is' keyword may not be used outside of a switch.")
   }
 
   def apply(v: Bits, vr: Bits*)(block: => Unit) {
-    Builder.error("The 'is' keyword may not be used outside of a switch.")
+    require(false, "The 'is' keyword may not be used outside of a switch.")
   }
 }
 
diff --git a/src/test/scala/chiselTests/ChiselSpec.scala b/src/test/scala/chiselTests/ChiselSpec.scala
index 8848d4f5..000880e2 100644
--- a/src/test/scala/chiselTests/ChiselSpec.scala
+++ b/src/test/scala/chiselTests/ChiselSpec.scala
@@ -11,7 +11,7 @@ import Chisel.testers._
 /** Common utility functions for Chisel unit tests. */
 trait ChiselRunners {
   def execute(t: => BasicTester): Boolean = TesterDriver.execute(() => t)
-  def elaborate(t: => Module): Circuit = Driver.elaborate(() => t)
+  def elaborate(t: => Module): Unit = Driver.elaborate(() => t)
 }
 
 /** Spec base class for BDD-style testers. */
diff --git a/src/test/scala/chiselTests/Reg.scala b/src/test/scala/chiselTests/Reg.scala
index 55c92b45..f2620d88 100644
--- a/src/test/scala/chiselTests/Reg.scala
+++ b/src/test/scala/chiselTests/Reg.scala
@@ -8,7 +8,7 @@ import Chisel.testers.BasicTester
 
 class RegSpec extends ChiselFlatSpec {
   "A Reg" should "throw an exception if not given any parameters" in {
-    a [ChiselException] should be thrownBy {
+    a [Exception] should be thrownBy {
       val reg = Reg()
     }
   }