From 753c534b1b2014d252e7562a39c3cd1cc16c8e76 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 13 Nov 2013 14:56:07 +0100
Subject: widen if unstable prefix

---
 src/dotty/tools/dotc/core/Decorators.scala   |  7 +++++++
 src/dotty/tools/dotc/core/Flags.scala        |  4 ++++
 src/dotty/tools/dotc/core/TypeComparer.scala | 10 +++++-----
 3 files changed, 16 insertions(+), 5 deletions(-)

(limited to 'src/dotty')

diff --git a/src/dotty/tools/dotc/core/Decorators.scala b/src/dotty/tools/dotc/core/Decorators.scala
index 7888d2f8c..eb287f411 100644
--- a/src/dotty/tools/dotc/core/Decorators.scala
+++ b/src/dotty/tools/dotc/core/Decorators.scala
@@ -98,6 +98,13 @@ object Decorators {
             (xs1 eq xs.tail)) xs
         else x1 :: xs1
       }
+
+    final def hasSameLengthAs[U](ys: List[U]): Boolean = {
+      @tailrec def loop(xs: List[T], ys: List[U]): Boolean =
+        if (xs.isEmpty) ys.isEmpty
+        else ys.nonEmpty && loop(xs.tail, ys.tail)
+      loop(xs, ys)
+    }
   }
 
   implicit class ListOfListDecorator[T](val xss: List[List[T]]) extends AnyVal {
diff --git a/src/dotty/tools/dotc/core/Flags.scala b/src/dotty/tools/dotc/core/Flags.scala
index 956b67ffb..70761ebf3 100644
--- a/src/dotty/tools/dotc/core/Flags.scala
+++ b/src/dotty/tools/dotc/core/Flags.scala
@@ -451,6 +451,10 @@ object Flags {
   /** An abstract class or a trait */
   final val AbstractOrTrait = Abstract | Trait
 
+  /** A local symbol, or one which has an expanded name (type parameters go from one to the other).
+   */
+  final val LocalOrExpanded = Local | ExpandedName
+
   /** Labeled `private` or `protected[local]` */
   final val PrivateOrLocal = Private | Local
 
diff --git a/src/dotty/tools/dotc/core/TypeComparer.scala b/src/dotty/tools/dotc/core/TypeComparer.scala
index 241c0e899..42ecb7a2a 100644
--- a/src/dotty/tools/dotc/core/TypeComparer.scala
+++ b/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -310,7 +310,7 @@ class TypeComparer(initctx: Context) extends DotClass {
         case tp1 @ MethodType(_, formals2) =>
           tp1.signature == tp2.signature &&
             /*(if (newMatch) subsumeParams(formals1, formals2, tp1.isJava, tp2.isJava)
-             else */matchingParams(formals1, formals2, tp1.isJava, tp2.isJava)) &&
+             else */matchingParams(formals1, formals2, tp1.isJava, tp2.isJava) &&
             tp1.isImplicit == tp2.isImplicit && // needed?
             isSubType(tp1.resultType, tp2.resultType.subst(tp2, tp1))
         case _ =>
@@ -674,8 +674,8 @@ class TypeComparer(initctx: Context) extends DotClass {
       }
     case tp1 @ MethodType(names1, formals1) =>
       tp2 match {
-        case tp2 @ MethodType(names2, formals2)
-/*        if newMatch && (tp1.isImplicit == tp2.isImplicit) && formals1.hasSameLengthAs(formals2) =>
+/*        case tp2 @ MethodType(names2, formals2)
+        if newMatch && (tp1.isImplicit == tp2.isImplicit) && formals1.hasSameLengthAs(formals2) =>
           tp1.derivedMethodType(
               mergeNames(names1, names2, nme.syntheticParamName),
               (formals1 zipWithConserve formals2)(_ | _),
@@ -748,8 +748,8 @@ class TypeComparer(initctx: Context) extends DotClass {
       }
     case tp1 @ MethodType(names1, formals1) =>
       tp2 match {
-        case tp2 @ MethodType(names2, formals2)
-/*        if newMatch && (tp1.isImplicit == tp2.isImplicit) && formals1.hasSameLengthAs(formals2) =>
+/*        case tp2 @ MethodType(names2, formals2)
+       if newMatch && (tp1.isImplicit == tp2.isImplicit) && formals1.hasSameLengthAs(formals2) =>
           tp1.derivedMethodType(
               mergeNames(names1, names2, nme.syntheticParamName),
               (formals1 zipWithConserve formals2)(_ & _),
-- 
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