Update check-files and error annotations

.. of tests explicitly checking implicits resolving to most specific

Author: EugeneFlesselle

tests/neg/i2974.scala

@@ -0,0 +1,24 @@
+
+trait Foo[-T]
+trait Bar[-T] extends Foo[T]
+
+object Test {
+
+  locally:
+    implicit val fa: Foo[Int] = ???
+    implicit val ba: Bar[Int] = ???
+    summon[Foo[Int]] // ok
+
+  locally:
+    implicit val fa: Foo[Int] = ???
+    implicit val ba: Bar[Any] = ???
+    summon[Foo[Int]] // ok
+
+  locally:
+    implicit val fa: Foo[Any] = ???
+    implicit val ba: Bar[Int] = ???
+    summon[Foo[Int]] // error: now ambiguous,
+    // was resolving to `ba` when using intermediate rules:
+    // better means specialize, but map all type arguments downwards
+
+}

tests/pos/i2974.scala

@@ -4,5 +4,5 @@ List(2, 4)
 HW
 ArraySeq(72, 108, 108, 32, 114, 108, 100)
 Map(bar -> 2)
-TreeMap(bar -> 2)
+Map(bar -> 2)
 Map(bar -> 2)

tests/run/enrich-gentraversable.check

@@ -47,7 +47,8 @@ object Test extends App {
 
     val tm = TreeMap(1 -> "foo", 2 -> "bar")
     val tmm = tm.filterMap { case (k, v) => if (k % 2 == 0) Some(v -> k) else None }
-    typed[TreeMap[String, Int]](tmm)
+    typed[Map[String, Int]](tmm) // was TreeMap, now Map,
+    // since `BuildFrom` is covariant in `That` and `TreeMap[String, Int] <:< Map[String, Int]`
     println(tmm)
 
     val mv = m.view

tests/run/enrich-gentraversable.scala

@@ -1 +1 @@
-barFoo
+fooFoo

tests/run/implicits_poly.check

@@ -149,8 +149,8 @@ object GivenImportOrderAtoB:
   object A { implicit val x: X = new X }
   object B { implicit val y: Y = new Y }
   class C {
-    import A._ // warn
-    import B._ // OK
+    import A._ // OK
+    import B._ // warn
     def t = implicitly[X]
   }
 
@@ -160,8 +160,8 @@ object GivenImportOrderBtoA:
   object A { implicit val x: X = new X }
   object B { implicit val y: Y = new Y }
   class C {
-    import B._ // OK
-    import A._ // warn
+    import B._ // warn
+    import A._ // OK
     def t = implicitly[X]
   }
 /* END : tests on given import order */