prohibit case-to-case inheritance instead of is...

prohibit case-to-case inheritance instead of issuing warning. closes
#4109. review by extempore, since it should make your life much easier
in the pattern matcher

6 files changed, 11 insertions, 4 deletions

diff --git a/test/files/neg/caseinherit.check b/test/files/neg/caseinherit.check
index 5630da2a3e..c185c82f70 100644
--- a/test/files/neg/caseinherit.check
+++ b/test/files/neg/caseinherit.check
@@ -1,10 +1,10 @@
-caseinherit.scala:2: error: case class `class B' has case ancestor `class A'.  Case-to-case inheritance has potentially dangerous bugs which are unlikely to be fixed.  You are strongly encouraged to instead use extractors to pattern match on non-leaf nodes.
+caseinherit.scala:2: error: case class `class B' has case ancestor `class A'. Case-to-case inheritance is prohibited. To overcome this limitation use extractors to pattern match on non-leaf nodes.
 case class B(y: Int) extends A(y)
            ^
-caseinherit.scala:3: error: case class `object Bippy' has case ancestor `class A'.  Case-to-case inheritance has potentially dangerous bugs which are unlikely to be fixed.  You are strongly encouraged to instead use extractors to pattern match on non-leaf nodes.
+caseinherit.scala:3: error: case class `object Bippy' has case ancestor `class A'. Case-to-case inheritance is prohibited. To overcome this limitation use extractors to pattern match on non-leaf nodes.
 case object Bippy extends A(55)
             ^
-caseinherit.scala:6: error: case class `class Dingus' has case ancestor `class A'.  Case-to-case inheritance has potentially dangerous bugs which are unlikely to be fixed.  You are strongly encouraged to instead use extractors to pattern match on non-leaf nodes.
+caseinherit.scala:6: error: case class `class Dingus' has case ancestor `class A'. Case-to-case inheritance is prohibited. To overcome this limitation use extractors to pattern match on non-leaf nodes.
 case class Dingus(y: Int) extends Innocent
            ^
 three errors found
diff --git a/test/files/neg/caseinherit.flags b/test/files/neg/caseinherit.flags
deleted file mode 100644
index e8fb65d50c..0000000000
--- a/test/files/neg/caseinherit.flags
+++ /dev/null
@@ -1 +0,0 @@
--Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/neg/t0816.check b/test/files/neg/t0816.check
new file mode 100644
index 0000000000..ff6489be99
--- /dev/null
+++ b/test/files/neg/t0816.check
@@ -0,0 +1,4 @@
+t0816.scala:5: error: case class `class Ctest' has case ancestor `class Btest'. Case-to-case inheritance is prohibited. To overcome this limitation use extractors to pattern match on non-leaf nodes.
+case class Ctest(override val data: String) extends Btest(data, true)
+           ^
+one error found
diff --git a/test/files/pos/t0816.scala b/test/files/neg/t0816.scala
index 0128a0ad72..0128a0ad72 100644
--- a/test/files/pos/t0816.scala
+++ b/test/files/neg/t0816.scala
diff --git a/test/files/neg/t425.check b/test/files/neg/t425.check
new file mode 100644
index 0000000000..671c128753
--- /dev/null
+++ b/test/files/neg/t425.check
@@ -0,0 +1,4 @@
+t425.scala:3: error: case class `class B' has case ancestor `class A'. Case-to-case inheritance is prohibited. To overcome this limitation use extractors to pattern match on non-leaf nodes.
+  case class B(override val x: Int, y: Double) extends A(x)
+             ^
+one error found
diff --git a/test/files/pos/t425.scala b/test/files/neg/t425.scala
index e50c50ac35..e50c50ac35 100644
--- a/test/files/pos/t425.scala
+++ b/test/files/neg/t425.scala