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.

8 files changed, 7 insertions, 11 deletions

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