Merge pull request #1826 from dotty-staging/fix-compile-stdlib

Make more parts of stdlib compile

3 files changed, 17 insertions, 3 deletions

diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
index 334306f19..8930983f3 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -757,8 +757,14 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
     if (args1.isEmpty) args2.isEmpty
     else args2.nonEmpty && {
       val v = tparams.head.paramVariance
-      (v > 0 || isSubType(args2.head, args1.head)) &&
-      (v < 0 || isSubType(args1.head, args2.head))
+      def isSub(tp1: Type, tp2: Type) = tp2 match {
+        case tp2: TypeBounds =>
+          tp2.contains(tp1)
+        case _ =>
+          (v > 0 || isSubType(tp2, tp1)) &&
+          (v < 0 || isSubType(tp1, tp2))
+      }
+      isSub(args1.head, args2.head)
     } && isSubArgs(args1.tail, args2.tail, tparams)
 
   /** Test whether `tp1` has a base type of the form `B[T1, ..., Tn]` where
diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
index db73daaa2..c2a7d7ea6 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeOps.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -552,7 +552,7 @@ trait TypeOps { this: Context => // TODO: Make standalone object.
   def dynamicsEnabled =
     featureEnabled(defn.LanguageModuleClass, nme.dynamics)
 
-  def testScala2Mode(msg: String, pos: Position) = {
+  def testScala2Mode(msg: => String, pos: Position) = {
     if (scala2Mode) migrationWarning(msg, pos)
     scala2Mode
   }
diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 64fa48071..636204f64 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -217,6 +217,14 @@ object Types {
       case _ => false
     }
 
+    /** Is this the type of a method with a leading empty parameter list?
+     */
+    def isNullaryMethod(implicit ctx: Context): Boolean = this match {
+      case MethodType(Nil, _) => true
+      case tp: PolyType => tp.resultType.isNullaryMethod
+      case _ => false
+    }
+
     /** Is this an alias TypeBounds? */
     def isAlias: Boolean = this.isInstanceOf[TypeAlias]