replace qualifierType by widenIfUnstable.

Also, throw an exception on internal errors rather than issuing an error (this helps debugging, should be reverted for production).

3 files changed, 7 insertions, 4 deletions

diff --git a/src/dotty/tools/dotc/typer/Applications.scala b/src/dotty/tools/dotc/typer/Applications.scala
index f4936cff0..7dc6eb799 100644
--- a/src/dotty/tools/dotc/typer/Applications.scala
+++ b/src/dotty/tools/dotc/typer/Applications.scala
@@ -483,7 +483,7 @@ trait Applications extends Compatibility { self: Typer =>
               }
             }
           case _ =>
-            fun1.qualifierType match {
+            fun1.tpe match {
               case ErrorType =>
                 tree.withType(ErrorType)
             }
diff --git a/src/dotty/tools/dotc/typer/Inferencing.scala b/src/dotty/tools/dotc/typer/Inferencing.scala
index 42b3564ce..50aa6c8d0 100644
--- a/src/dotty/tools/dotc/typer/Inferencing.scala
+++ b/src/dotty/tools/dotc/typer/Inferencing.scala
@@ -90,6 +90,8 @@ object Inferencing {
       }
       typer.interpolateAndAdapt(targ, formal)
     }
+
+    override def toString = s"FunProto(${args mkString ","} => $resultType)"
   }
 
   case class ViewProto(argType: Type, override val resultType: Type)(implicit ctx: Context) extends CachedGroundType with ProtoType {
@@ -223,6 +225,7 @@ object Inferencing {
       println(s"interpolate undet vars in ${tp.show}, pos = ${tree.pos}, mode = ${ctx.mode}, undets = ${ctx.typerState.undetVars map (tvar => s"${tvar.show}@${tvar.owningTree.pos}")}")
       println(s"qualifying undet vars: ${ctx.typerState.undetVars filter qualifies map (_.show)}")
       println(s"fulltype: $tp") // !!! DEBUG
+      println(s"constraint: ${ctx.typerState.constraint.show}")
 
       def qualifies(tvar: TypeVar) = tree contains tvar.owningTree
       val vs = tp.variances(tvar =>
diff --git a/src/dotty/tools/dotc/typer/Typer.scala b/src/dotty/tools/dotc/typer/Typer.scala
index 08bf6badf..c7b79bad3 100644
--- a/src/dotty/tools/dotc/typer/Typer.scala
+++ b/src/dotty/tools/dotc/typer/Typer.scala
@@ -89,7 +89,7 @@ class Typer extends Namer with Applications with Implicits {
   }
 
   def checkedSelectionType(qual1: Tree, tree: untpd.RefTree)(implicit ctx: Context): Type = {
-    val ownType = selectionType(qual1.qualifierType, tree.name, tree.pos)
+    val ownType = selectionType(qual1.tpe.widenIfUnstable, tree.name, tree.pos)
     if (!ownType.isError) checkAccessible(ownType, qual1.isInstanceOf[Super], tree.pos)
     ownType
   }
@@ -516,7 +516,7 @@ class Typer extends Namer with Applications with Implicits {
     val ownType = meth1.tpe.widen match {
       case mt: MethodType =>
         if (!mt.isDependent) mt.toFunctionType
-        else errorType(i"internal error: cannot turn dependent method type $mt into closure", tree.pos)
+        else throw new Error(s"internal error: cannot turn dependent method type $mt into closure, position = ${tree.pos}") // !!! DEBUG. Eventually, convert to an error?
       case tp =>
         errorType(i"internal error: closing over non-method $tp", tree.pos)
     }
@@ -638,7 +638,7 @@ class Typer extends Namer with Applications with Implicits {
 
   def typedSingletonTypeTree(tree: untpd.SingletonTypeTree)(implicit ctx: Context): SingletonTypeTree = track("typedSingletonTypeTree") {
     val ref1 = typedExpr(tree.ref)
-    checkStable(ref1.qualifierType, tree.pos)
+    checkStable(ref1.tpe.widenIfUnstable, tree.pos)
     cpy.SingletonTypeTree(tree, ref1) withType ref1.tpe
   }