From 31af865656ecc352c39ce919981e9b50d42a3237 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 29 Jun 2016 19:48:40 +0200
Subject: Fix condition for lambda abstracting in Namer

The previous condition could make a (derived) type a * type
for a little while even though it had type parameters. This
loophole caused collection/generic/MapFactory.scala and with
it compile-stdlib to fail.
Refinement for knownHK for PolyParams

pos test t2082.scala shows that knownHK can be constructed before
the binder PolyType of a PolyParam is initialized.
---
 src/dotty/tools/dotc/core/TypeApplications.scala | 10 +++-------
 src/dotty/tools/dotc/core/Types.scala            |  6 +++++-
 src/dotty/tools/dotc/typer/Namer.scala           |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

(limited to 'src/dotty/tools')

diff --git a/src/dotty/tools/dotc/core/TypeApplications.scala b/src/dotty/tools/dotc/core/TypeApplications.scala
index fc8876d09..c0728a8fb 100644
--- a/src/dotty/tools/dotc/core/TypeApplications.scala
+++ b/src/dotty/tools/dotc/core/TypeApplications.scala
@@ -494,7 +494,9 @@ class TypeApplications(val self: Type) extends AnyVal {
     case self: SingletonType => -1
     case self: TypeVar => self.origin.knownHK
     case self: WildcardType => self.optBounds.knownHK
+    case self: PolyParam => self.underlying.knownHK
     case self: TypeProxy => self.underlying.knownHK
+    case NoType => 0
     case _ => -1
   }
 
@@ -666,13 +668,7 @@ class TypeApplications(val self: Type) extends AnyVal {
           instTop(tp.ref)
         case tp =>
           inst.tyconIsHK = tp.isHK
-          val res = inst(tp)
-          tp match {
-            case tp: WildcardType =>
-              println(s"inst $tp --> $res")
-            case _ =>
-          }
-          res
+          inst(tp)
       }
 
       def isLazy(tp: Type): Boolean = tp.strictDealias match {
diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index 986a9c292..d3e97b492 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -2765,7 +2765,11 @@ object Types {
 
     def paramName = binder.paramNames(paramNum)
 
-    override def underlying(implicit ctx: Context): Type = binder.paramBounds(paramNum)
+    override def underlying(implicit ctx: Context): Type = {
+      val bounds = binder.paramBounds
+      if (bounds == null) NoType // this can happen if the PolyType is not initialized yet
+      else bounds(paramNum)
+    }
     // no customized hashCode/equals needed because cycle is broken in PolyType
     override def toString = s"PolyParam($paramName)"
 
diff --git a/src/dotty/tools/dotc/typer/Namer.scala b/src/dotty/tools/dotc/typer/Namer.scala
index 7982f288d..bc8f8e281 100644
--- a/src/dotty/tools/dotc/typer/Namer.scala
+++ b/src/dotty/tools/dotc/typer/Namer.scala
@@ -935,7 +935,7 @@ class Namer { typer: Typer =>
     //val toParameterize = tparamSyms.nonEmpty && !isDerived
     //val needsLambda = sym.allOverriddenSymbols.exists(_ is HigherKinded) && !isDerived
     def abstracted(tp: Type): Type =
-      if (tparamSyms.nonEmpty && !isDerived) tp.LambdaAbstract(tparamSyms)
+      if (tparamSyms.nonEmpty && !tp.isHK) tp.LambdaAbstract(tparamSyms)
       //else if (toParameterize) tp.parameterizeWith(tparamSyms)
       else tp
 
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