SI-7070 Turn restriction on companions in pkg objs into warning

The implementation restriction created from SI-5954 in
3ef487ecb6733bfe3c13d89780ebcfc81f9a5ea0 has two problems.

1) The problematic code works fine if compile with sbt. That means the
restriction is breaking some people needlessly.

2) It's not binary compatible.

To fix all that this commit changes the error into a warning and removes
the setting used to get around the restriction.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 026c130a87..795ad7e5c7 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1914,29 +1914,29 @@ trait Typers extends Modes with Adaptations with Tags {
 
       // SI-5954. On second compile of a companion class contained in a package object we end up
       // with some confusion of names which leads to having two symbols with the same name in the
-      // same owner. Until that can be straightened out we can't allow companion objects in package
+      // same owner. Until that can be straightened out we will warn on companion objects in package
       // objects. But this code also tries to be friendly by distinguishing between case classes and
       // user written companion pairs
-      def restrictPackageObjectMembers(mdef : ModuleDef) = for (m <- mdef.symbol.info.members) {
+      def warnPackageObjectMembers(mdef : ModuleDef) = for (m <- mdef.symbol.info.members) {
         // ignore synthetic objects, because the "companion" object to a case class is synthetic and
         // we only want one error per case class
         if (!m.isSynthetic) {
           // can't handle case classes in package objects
-          if (m.isCaseClass) pkgObjectRestriction(m, mdef, "case")
+          if (m.isCaseClass) pkgObjectWarning(m, mdef, "case")
           // can't handle companion class/object pairs in package objects
           else if ((m.isClass && m.companionModule != NoSymbol && !m.companionModule.isSynthetic) ||
                    (m.isModule && m.companionClass != NoSymbol && !m.companionClass.isSynthetic))
-                     pkgObjectRestriction(m, mdef, "companion")
+                     pkgObjectWarning(m, mdef, "companion")
         }
 
-        def pkgObjectRestriction(m : Symbol, mdef : ModuleDef, restricted : String) = {
+        def pkgObjectWarning(m : Symbol, mdef : ModuleDef, restricted : String) = {
           val pkgName = mdef.symbol.ownerChain find (_.isPackage) map (_.decodedName) getOrElse mdef.symbol.toString
-          context.error(if (m.pos.isDefined) m.pos else mdef.pos, s"implementation restriction: package object ${pkgName} cannot contain ${restricted} ${m}. Instead, ${m} should be placed directly in package ${pkgName}.")
+          context.warning(if (m.pos.isDefined) m.pos else mdef.pos, s"${m} should be placed directly in package ${pkgName} instead of package object ${pkgName}. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.")
         }
       }
 
-      if (!settings.companionsInPkgObjs.value && mdef.symbol.isPackageObject)
-        restrictPackageObjectMembers(mdef)
+      if (mdef.symbol.isPackageObject)
+        warnPackageObjectMembers(mdef)
 
       treeCopy.ModuleDef(mdef, typedMods, mdef.name, impl2) setType NoType
     }