Proposed fix for #2144 plus test case.

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@19399 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

src/compiler/scala/tools/nsc/typechecker/Typers.scala

@@ -1700,8 +1700,13 @@ trait Typers { self: Analyzer =>
         computeParamAliases(meth.owner, vparamss1, rhs1)
       if (tpt1.tpe.typeSymbol != NothingClass && !context.returnsSeen) rhs1 = checkDead(rhs1)
 
-      if (meth.owner.isRefinementClass && meth.allOverriddenSymbols.isEmpty)
-        for (vparams <- ddef.vparamss; vparam <- vparams) 
+      // If only refinement owned methods are checked, invalid code can result; see ticket #2144.
+      def requiresStructuralCheck = meth.allOverriddenSymbols.isEmpty && (
+        meth.owner.isRefinementClass ||
+        (!meth.isConstructor && !meth.isSetter && meth.owner.isAnonymousClass)
+      )
+      if (requiresStructuralCheck)
+        for (vparam <- ddef.vparamss.flatten)
           checkStructuralCondition(meth.owner, vparam)
 
       if (phase.id <= currentRun.typerPhase.id && meth.owner.isClass &&

test/files/neg/bug2144.check

@@ -0,0 +1,4 @@
+bug2144.scala:2: error: Parameter type in structural refinement may not refer to abstract type defined outside that same refinement
+  def foo[A](a: A) = new { def bar(x: A): A = x }
+                                      ^
+one error found

test/files/neg/bug2144.scala

@@ -0,0 +1,3 @@
+object Test {
+  def foo[A](a: A) = new { def bar(x: A): A = x }
+}