Move warn tests from tests/neg to tests/warn: Batch 2

Author: szymon-rd

tests/neg/14034b.scala

@@ -1,10 +1,11 @@
 //> using options -source future -feature -Xfatal-warnings
 
 package adhoc
-class B extends A  // error: adhoc-extension (under -strict -feature -Xfatal-warnings)
-class C extends A  // error
+class B extends A  // warn: adhoc-extension (under -strict -feature -Xfatal-warnings)
+class C extends A  // warn
 
 object O {
-  val a = new A {}  // error
-  object E extends A  // error
-}
+  val a = new A {}  // warn
+  object E extends A  // warn
+}
+// nopos-error: No warnings can be incurred under -Werror.

tests/neg/17284.scala

@@ -13,12 +13,12 @@ def test(c: Cap, other: String): Unit =
   val x3a: () -> String = s1
   val s2 = () => if x1 == null then "" else "abc"
   val x4: C^{s2} = ??? // OK
-  val x5: C^{c, c} = ??? // error: redundant // error: redundant
+  val x5: C^{c, c} = ??? // warn: redundant // warn: redundant
   // val x6: C^{c}^{c} = ??? // would be syntax error
-  val x7: Cap^{c} = ??? // error: redundant
+  val x7: Cap^{c} = ??? // warn: redundant
   // val x8: C^{c}^{cap} = ??? // would be syntax error
-  val x9: C^{c, cap}  = ??? // error: redundant
-  val x10: C^{cap, c} = ??? // error: redundant
+  val x9: C^{c, cap}  = ??? // warn: redundant
+  val x10: C^{cap, c} = ??? // warn: redundant
 
   def even(n: Int): Boolean = if n == 0 then true else odd(n - 1)
   def odd(n: Int): Boolean = if n == 1 then true else even(n - 1)
@@ -34,4 +34,5 @@ def test(c: Cap, other: String): Unit =
     if n == 0 then true else od(n - 1)
   val y3: String^{ev} = ??? // error cs is empty
 
-  ()
+  ()
+// nopos-error: No warnings can be incurred under -Werror.

tests/neg/18493.check

@@ -5,4 +5,5 @@ import scala.reflect.ClassTag
 
 def f3_1m[T: ClassTag](x: Any): Unit =
   x match
-    case _: T => // error
+    case _: T => // warn
+// nopos-error: No warnings can be incurred under -Werror.

tests/neg/adhoc-extension/B.scala

@@ -5,4 +5,5 @@ import scala.reflect.ClassTag
 
 def f3_1[T: ClassTag](x: Any): Unit =
   x match
-    case _: T => // error
+    case _: T => // warn
+// nopos-error: No warnings can be incurred under -Werror.