Merge pull request #2079 from JamesIry/2.10.x_SI-7070

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

12 files changed, 15 insertions, 23 deletions

diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index 0a98d45cac..3df6334ec1 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -175,7 +175,6 @@ trait ScalaSettings extends AbsScalaSettings
   val etaExpandKeepsStar = BooleanSetting ("-Yeta-expand-keeps-star", "Eta-expand varargs methods to T* rather than Seq[T].  This is a temporary option to ease transition.")
   val Yinvalidate     = StringSetting     ("-Yinvalidate", "classpath-entry", "Invalidate classpath entry before run", "")
   val noSelfCheck     = BooleanSetting    ("-Yno-self-type-checks", "Suppress check for self-type conformance among inherited members.")
-  val companionsInPkgObjs = BooleanSetting("-Ycompanions-in-pkg-objs", "Allow companion objects and case classes in package objects. See issue SI-5954.")
   val YvirtClasses    = false // too embryonic to even expose as a -Y //BooleanSetting    ("-Yvirtual-classes", "Support virtual classes")
 
   val exposeEmptyPackage = BooleanSetting("-Yexpose-empty-package", "Internal only: expose the empty package.").internalOnly()
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index f518712701..2103f669c3 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1802,29 +1802,29 @@ 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
     }
diff --git a/src/reflect/scala/reflect/internal/settings/MutableSettings.scala b/src/reflect/scala/reflect/internal/settings/MutableSettings.scala
index ec3501d5bc..81368df7a6 100644
--- a/src/reflect/scala/reflect/internal/settings/MutableSettings.scala
+++ b/src/reflect/scala/reflect/internal/settings/MutableSettings.scala
@@ -47,6 +47,4 @@ abstract class MutableSettings extends AbsSettings {
   def XoldPatmat: BooleanSetting
   def XnoPatmatAnalysis: BooleanSetting
   def XfullLubs: BooleanSetting
-  def companionsInPkgObjs: BooleanSetting
-  
 }
diff --git a/src/reflect/scala/reflect/runtime/Settings.scala b/src/reflect/scala/reflect/runtime/Settings.scala
index 2d5b76f094..0e0cf3fc40 100644
--- a/src/reflect/scala/reflect/runtime/Settings.scala
+++ b/src/reflect/scala/reflect/runtime/Settings.scala
@@ -43,7 +43,6 @@ private[reflect] class Settings extends MutableSettings {
   val printtypes        = new BooleanSetting(false)
   val uniqid            = new BooleanSetting(false)
   val verbose           = new BooleanSetting(false)
-  val companionsInPkgObjs = new BooleanSetting(false)
 
   val Yrecursion        = new IntSetting(0)
   val maxClassfileName  = new IntSetting(255)
diff --git a/test/files/neg/t5954.check b/test/files/neg/t5954.check
index 3ca47cd430..ed10658b24 100644
--- a/test/files/neg/t5954.check
+++ b/test/files/neg/t5954.check
@@ -1,16 +1,16 @@
-t5954.scala:36: error: implementation restriction: package object A cannot contain case class D. Instead, class D should be placed directly in package A.
+t5954.scala:36: error: class D should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
   case class D()
              ^
-t5954.scala:35: error: implementation restriction: package object A cannot contain companion object C. Instead, object C should be placed directly in package A.
+t5954.scala:35: error: object C should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
   object C
          ^
-t5954.scala:34: error: implementation restriction: package object A cannot contain companion trait C. Instead, trait C should be placed directly in package A.
+t5954.scala:34: error: trait C should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
   trait C
         ^
-t5954.scala:33: error: implementation restriction: package object A cannot contain companion object B. Instead, object B should be placed directly in package A.
+t5954.scala:33: error: object B should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
   object B
          ^
-t5954.scala:32: error: implementation restriction: package object A cannot contain companion class B. Instead, class B should be placed directly in package A.
+t5954.scala:32: error: class B should be placed directly in package A instead of package object A. Under some circumstances companion objects and case classes in package objects can fail to recompile. See https://issues.scala-lang.org/browse/SI-5954.
   class B
         ^
 5 errors found
diff --git a/test/files/neg/t5954.flags b/test/files/neg/t5954.flags
new file mode 100644
index 0000000000..85d8eb2ba2
--- /dev/null
+++ b/test/files/neg/t5954.flags
@@ -0,0 +1 @@
+-Xfatal-warnings
diff --git a/test/files/neg/t5954.scala b/test/files/neg/t5954.scala
index 9e6f5392c7..3ccb5ed3ff 100644
--- a/test/files/neg/t5954.scala
+++ b/test/files/neg/t5954.scala
@@ -1,4 +1,4 @@
-// if you ever think you've fixed the underlying reason for the implementation restrictions
+// if you ever think you've fixed the underlying reason for the warning
 // imposed by SI-5954, then here's a test that should pass with two "succes"es
 //
 //import scala.tools.partest._
diff --git a/test/files/pos/package-case.flags b/test/files/pos/package-case.flags
deleted file mode 100644
index 2f174c4732..0000000000
--- a/test/files/pos/package-case.flags
+++ /dev/null
@@ -1 +0,0 @@
--Ycompanions-in-pkg-objs
diff --git a/test/files/pos/t2130-1.flags b/test/files/pos/t2130-1.flags
deleted file mode 100644
index 2f174c4732..0000000000
--- a/test/files/pos/t2130-1.flags
+++ /dev/null
@@ -1 +0,0 @@
--Ycompanions-in-pkg-objs
diff --git a/test/files/pos/t2130-2.flags b/test/files/pos/t2130-2.flags
deleted file mode 100644
index 2f174c4732..0000000000
--- a/test/files/pos/t2130-2.flags
+++ /dev/null
@@ -1 +0,0 @@
--Ycompanions-in-pkg-objs
diff --git a/test/files/pos/t3999b.flags b/test/files/pos/t3999b.flags
deleted file mode 100644
index 2f174c4732..0000000000
--- a/test/files/pos/t3999b.flags
+++ /dev/null
@@ -1 +0,0 @@
--Ycompanions-in-pkg-objs
diff --git a/test/files/pos/t4052.flags b/test/files/pos/t4052.flags
deleted file mode 100644
index 2f174c4732..0000000000
--- a/test/files/pos/t4052.flags
+++ /dev/null
@@ -1 +0,0 @@
--Ycompanions-in-pkg-objs