diff --git a/src/main/scala/uncore/tilelink2/LazyModule.scala b/src/main/scala/uncore/tilelink2/LazyModule.scala
index 92c6e0eb..48fffb48 100644
--- a/src/main/scala/uncore/tilelink2/LazyModule.scala
+++ b/src/main/scala/uncore/tilelink2/LazyModule.scala
@@ -24,10 +24,7 @@ abstract class LazyModule
   }
 
   def name = getClass.getName.split('.').last
-  def line = info match {
-    case SourceLine(filename, line, col) => s" ($filename:$line:$col)"
-    case _ => ""
-  }
+  def line = sourceLine(info)
 
   def module: LazyModuleImp
   implicit val lazyModule = this
@@ -50,7 +47,8 @@ object LazyModule
     // Make sure the user put LazyModule around modules in the correct order
     // If this require fails, probably some grandchild was missing a LazyModule
     // ... or you applied LazyModule twice
-    require (!stack.isEmpty && (stack.head eq bc))
+    require (!stack.isEmpty, s"LazyModule() applied to ${bc.name} twice ${sourceLine(sourceInfo)}")
+    require (stack.head eq bc, s"LazyModule() applied to ${bc.name} before ${stack.head.name} ${sourceLine(sourceInfo)}")
     stack = stack.tail
     bc.info = sourceInfo
     bc
@@ -60,7 +58,7 @@ object LazyModule
 abstract class LazyModuleImp(outer: LazyModule) extends Module
 {
   // .module had better not be accessed while LazyModules are still being built!
-  require (LazyModule.stack.isEmpty)
+  require (LazyModule.stack.isEmpty, s"${outer.name}.module was constructed before LazyModule() was run on ${LazyModule.stack.head.name}")
 
   override def desiredName = outer.name
   outer.instantiate()
diff --git a/src/main/scala/uncore/tilelink2/Nodes.scala b/src/main/scala/uncore/tilelink2/Nodes.scala
index a2231bbd..9d9a8aed 100644
--- a/src/main/scala/uncore/tilelink2/Nodes.scala
+++ b/src/main/scala/uncore/tilelink2/Nodes.scala
@@ -29,39 +29,46 @@ class RootNode
 }
 
 class BaseNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(
-  private val oFn: Option[Seq[PO] => PO],
-  private val iFn: Option[Seq[PI] => PI],
+  private val oFn: (Int, Seq[PO]) => Seq[PO],
+  private val iFn: (Int, Seq[PI]) => Seq[PI],
   private val numPO: Range.Inclusive,
   private val numPI: Range.Inclusive) extends RootNode
 {
   // At least 0 ports must be supported
-  require (!numPO.isEmpty)
-  require (!numPI.isEmpty)
-  require (numPO.start >= 0)
-  require (numPI.start >= 0)
+  def name = lazyModule.name + "." + getClass.getName.split('.').last
+  require (!numPO.isEmpty, s"No number of outputs would be acceptable to ${name}${lazyModule.line}")
+  require (!numPI.isEmpty, s"No number of inputs would be acceptable to ${name}${lazyModule.line}")
+  require (numPO.start >= 0, s"${name} accepts a negative number of outputs${lazyModule.line}")
+  require (numPI.start >= 0, s"${name} accepts a negative number of inputs${lazyModule.line}")
 
   val noOs = numPO.size == 1 && numPO.contains(0)
   val noIs = numPI.size == 1 && numPI.contains(0)
 
-  require (noOs || oFn.isDefined)
-  require (noIs || iFn.isDefined)
-
-  private val accPO = ListBuffer[BaseNode[PO, PI, EO, EI, B]]()
-  private val accPI = ListBuffer[BaseNode[PO, PI, EO, EI, B]]()
+  private val accPO = ListBuffer[(Int, BaseNode[PO, PI, EO, EI, B])]()
+  private val accPI = ListBuffer[(Int, BaseNode[PO, PI, EO, EI, B])]()
   private var oRealized  = false
   private var iRealized = false
 
-  def name = lazyModule.name + "." + getClass.getName.split('.').last
   private def reqO() = require(numPO.contains(accPO.size), s"${name} has ${accPO.size} outputs, expected ${numPO}${lazyModule.line}")
   private def reqI() = require(numPI.contains(accPI.size), s"${name} has ${accPI.size} inputs, expected ${numPI}${lazyModule.line}")
+  protected def reqE(o: Int, i: Int) = require(i == o, s"${name} has ${i} inputs and ${o} outputs; they must match${lazyModule.line}")
 
   private lazy val oPorts = { oRealized = true; reqO(); accPO.result() }
   private lazy val iPorts = { iRealized = true; reqI(); accPI.result() }
-  private lazy val oParams : Option[PO] = oFn.map(_(iPorts.map(_.oParams.get)))
-  private lazy val iParams : Option[PI] = iFn.map(_(oPorts.map(_.iParams.get)))
 
-  lazy val edgesOut = oPorts.map { n => imp.edgeO(oParams.get, n.iParams.get) }
-  lazy val edgesIn  = iPorts.map { n => imp.edgeI(n.oParams.get, iParams.get) }
+  private lazy val oParams : Seq[PO] = {
+    val o = oFn(oPorts.size, iPorts.map{ case (i, n) => n.oParams(i) })
+    reqE(oPorts.size, o.size)
+    o
+  }
+  private lazy val iParams : Seq[PI] = {
+    val i = iFn(iPorts.size, oPorts.map{ case (o, n) => n.iParams(o) })
+    reqE(i.size, iPorts.size)
+    i
+  }
+
+  lazy val edgesOut = (oPorts zip oParams).map { case ((i, n), o) => imp.edgeO(o, n.iParams(i)) }
+  lazy val edgesIn  = (iPorts zip iParams).map { case ((o, n), i) => imp.edgeI(n.oParams(o), i) }
 
   lazy val bundleOut = imp.bundleO(edgesOut)
   lazy val bundleIn  = imp.bundleI(edgesIn)
@@ -71,14 +78,15 @@ class BaseNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(
 
   // source.edge(sink)
   protected[tilelink2] def edge(x: BaseNode[PO, PI, EO, EI, B])(implicit sourceInfo: SourceInfo) = {
-    require (!noOs)
-    require (!oRealized)
-    require (!x.noIs)
-    require (!x.iRealized)
+    val info = sourceLine(sourceInfo, " at ", "")
+    require (!noOs, s"${name}${lazyModule.line} was incorrectly connected as a source" + info)
+    require (!oRealized, s"${name}${lazyModule.line} was incorrectly connected as a source after it's .module was used" + info)
+    require (!x.noIs, s"${x.name}${x.lazyModule.line} was incorrectly connected as a sink" + info)
+    require (!x.iRealized, s"${x.name}${x.lazyModule.line} was incorrectly connected as a sink after it's .module was used" + info)
     val i = x.accPI.size
     val o = accPO.size
-    accPO += x
-    x.accPI += this
+    accPO += ((i, x))
+    x.accPI += ((o, this))
     () => {
       imp.connect(connectOut(o), edgesOut(o), x.connectIn(i), x.edgesIn(i))
     }
@@ -86,7 +94,7 @@ class BaseNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(
 }
 
 class IdentityNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])
-  extends BaseNode(imp)(Some{case Seq(x) => x}, Some{case Seq(x) => x}, 1 to 1, 1 to 1)
+  extends BaseNode(imp)({case (_, s) => s}, {case (_, s) => s}, 0 to 999, 0 to 999)
 
 class OutputNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B]) extends IdentityNode(imp)
 {
@@ -101,21 +109,21 @@ class InputNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B]) exte
 }
 
 class SourceNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(po: PO, num: Range.Inclusive = 1 to 1)
-  extends BaseNode(imp)(Some{case Seq() => po}, None, num, 0 to 0)
+  extends BaseNode(imp)({case (n, Seq()) => Seq.fill(n)(po)}, {case (0, _) => Seq()}, num, 0 to 0)
 {
-  require (num.end >= 1)
+  require (num.end >= 1, s"${name} is a source which does not accept outputs${lazyModule.line}")
 }
 
 class SinkNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])(pi: PI, num: Range.Inclusive = 1 to 1)
-  extends BaseNode(imp)(None, Some{case Seq() => pi}, 0 to 0, num)
+  extends BaseNode(imp)({case (0, _) => Seq()}, {case (n, Seq()) => Seq.fill(n)(pi)}, 0 to 0, num)
 {
-  require (num.end >= 1)
+  require (num.end >= 1, s"${name} is a sink which does not accept inputs${lazyModule.line}")
 }
 
 class InteriorNode[PO, PI, EO, EI, B <: Data](imp: NodeImp[PO, PI, EO, EI, B])
   (oFn: Seq[PO] => PO, iFn: Seq[PI] => PI, numPO: Range.Inclusive, numPI: Range.Inclusive)
-  extends BaseNode(imp)(Some(oFn), Some(iFn), numPO, numPI)
+  extends BaseNode(imp)({case (n,s) => Seq.fill(n)(oFn(s))}, {case (n,s) => Seq.fill(n)(iFn(s))}, numPO, numPI)
 {
-  require (numPO.end >= 1)
-  require (numPI.end >= 1)
+  require (numPO.end >= 1, s"${name} is an adapter which does not accept outputs${lazyModule.line}")
+  require (numPI.end >= 1, s"${name} is an adapter which does not accept inputs${lazyModule.line}")
 }
diff --git a/src/main/scala/uncore/tilelink2/package.scala b/src/main/scala/uncore/tilelink2/package.scala
index cb78a633..050a4b6d 100644
--- a/src/main/scala/uncore/tilelink2/package.scala
+++ b/src/main/scala/uncore/tilelink2/package.scala
@@ -1,6 +1,7 @@
 package uncore
 
 import Chisel._
+import chisel3.internal.sourceinfo.{SourceInfo, SourceLine, UnlocatableSourceInfo}
 
 package object tilelink2
 {
@@ -9,4 +10,9 @@ package object tilelink2
   def OH1ToUInt(x: UInt) = OHToUInt((x << 1 | UInt(1)) ^ x)
   def UIntToOH1(x: UInt, width: Int) = ~(SInt(-1, width=width).asUInt << x)(width-1, 0)
   def trailingZeros(x: Int) = if (x > 0) Some(log2Ceil(x & -x)) else None
+
+  def sourceLine(sourceInfo: SourceInfo, prefix: String = " (", suffix: String = ")") = sourceInfo match {
+    case SourceLine(filename, line, col) => s"$prefix$filename:$line:$col$suffix"
+    case _ => ""
+  }
 }