SI-7020 Deterministic warnings for pattern matcher, take 2

The previous swing at determinism, ebb01e05cbe4, made decent
contact but apparently didn't hit it out of the park. The test
wavered every hundred or so runs, as witnessed occasionally in
nightly builds or pull request validation.

I setup a test to run neg/7020.scala a few hundred times, and
could trigger the failure reliably.

I then swept through the pattern matcher in search of HashMap and
HashSet creation, and changed them all to the Linked variety.
The results of that are published in retronym#ticket/7020-3 [1].

This commit represents the careful whittling down of that patch
to the minimal change required to exhibit determinism.

[1] https://github.com/retronym/scala/compare/ticket/7020-3

3 files changed, 0 insertions, 50 deletions

diff --git a/test/disabled/neg/t7020.check b/test/disabled/neg/t7020.check
deleted file mode 100644
index f9600ca7fc..0000000000
--- a/test/disabled/neg/t7020.check
+++ /dev/null
@@ -1,19 +0,0 @@
-t7020.scala:3: warning: match may not be exhaustive.
-It would fail on the following inputs: List((x: Int forSome x not in (1, 2, 4, 5, 6, 7))), List((x: Int forSome x not in (1, 2, 4, 5, 6, 7)), _), List(1, _), List(2, _), List(4, _), List(5, _), List(6, _), List(7, _), List(??, _), List(_, _)
-  List(5) match {
-      ^
-t7020.scala:10: warning: match may not be exhaustive.
-It would fail on the following inputs: List((x: Int forSome x not in (1, 2, 4, 5, 6, 7))), List((x: Int forSome x not in (1, 2, 4, 5, 6, 7)), _), List(1, _), List(2, _), List(4, _), List(5, _), List(6, _), List(7, _), List(??, _), List(_, _)
-  List(5) match {
-      ^
-t7020.scala:17: warning: match may not be exhaustive.
-It would fail on the following inputs: List((x: Int forSome x not in (1, 2, 4, 5, 6, 7))), List((x: Int forSome x not in (1, 2, 4, 5, 6, 7)), _), List(1, _), List(2, _), List(4, _), List(5, _), List(6, _), List(7, _), List(??, _), List(_, _)
-  List(5) match {
-      ^
-t7020.scala:24: warning: match may not be exhaustive.
-It would fail on the following inputs: List((x: Int forSome x not in (1, 2, 4, 5, 6, 7))), List((x: Int forSome x not in (1, 2, 4, 5, 6, 7)), _), List(1, _), List(2, _), List(4, _), List(5, _), List(6, _), List(7, _), List(??, _), List(_, _)
-  List(5) match {
-      ^
-error: No warnings can be incurred under -Xfatal-warnings.
-four warnings found
-one error found
diff --git a/test/disabled/neg/t7020.flags b/test/disabled/neg/t7020.flags
deleted file mode 100644
index e8fb65d50c..0000000000
--- a/test/disabled/neg/t7020.flags
+++ /dev/null
@@ -1 +0,0 @@
--Xfatal-warnings
\ No newline at end of file
diff --git a/test/disabled/neg/t7020.scala b/test/disabled/neg/t7020.scala
deleted file mode 100644
index cc5421bab1..0000000000
--- a/test/disabled/neg/t7020.scala
+++ /dev/null
@@ -1,30 +0,0 @@
-object Test {
-  // warning was non-deterministic
-  List(5) match {
-    case 1 :: Nil | 2 :: Nil  =>
-    case (x@(4 | 5 | 6)) :: Nil =>
-    case 7 :: Nil  =>
-    case Nil =>
-  }
-
-  List(5) match {
-    case 1 :: Nil | 2 :: Nil  =>
-    case (x@(4 | 5 | 6)) :: Nil =>
-    case 7 :: Nil  =>
-    case Nil =>
-  }
-
-  List(5) match {
-    case 1 :: Nil | 2 :: Nil  =>
-    case (x@(4 | 5 | 6)) :: Nil =>
-    case 7 :: Nil  =>
-    case Nil =>
-  }
-
-  List(5) match {
-    case 1 :: Nil | 2 :: Nil  =>
-    case (x@(4 | 5 | 6)) :: Nil =>
-    case 7 :: Nil  =>
-    case Nil =>
-  }
-}