tweak tests, add limitation errors

After the fix of the soundness issue, sometimes we infer universal capabilities
where it is not necessary. This results in completeness issues.

Author: Linyxus

tests/pos-custom-args/captures/boxmap.scala renamed to tests/neg-custom-args/boxmap.scala

@@ -15,5 +15,7 @@ def lazymap[A <: Top, B <: Top](b: Box[A])(f: A => B): {f} (() -> Box[B]) =
 def test[A <: Top, B <: Top] =
   def lazymap[A <: Top, B <: Top](b: Box[A])(f: A => B) =
     () => b[Box[B]]((x: A) => box(f(x)))
-  val x: (b: Box[A]) -> (f: A => B) -> (() -> Box[B]) = lazymap[A, B]
+  val x0: (b: Box[A]) -> (f: A => B) -> (() -> Box[B]) = lazymap[A, B]  // error
+  val x: (b: Box[A]) -> (f: A => B) -> {f} (() -> Box[B]) = lazymap[A, B]  // error // limitation
+  val y: (b: Box[A]) -> (f: A => B) -> {*} (() -> Box[B]) = lazymap[A, B]  // works
   ()

tests/pos-custom-args/captures/lazyref.scala renamed to tests/neg-custom-args/captures/lazyref-pos.scala

@@ -9,7 +9,7 @@ def map[A, B](ref: {*} LazyRef[A], f: A => B): {f, ref} LazyRef[B] =
   new LazyRef(() => f(ref.elem()))
 
 def mapc[A, B]: (ref: {*} LazyRef[A], f: A => B) => {f, ref} LazyRef[B] =
-  (ref1, f1) => map[A, B](ref1, f1)
+  (ref1, f1) => map[A, B](ref1, f1)  // error // limitation
 
 def test(cap1: Cap, cap2: Cap) =
   def f(x: Int) = if cap1 == cap1 then x else 0

tests/neg-custom-args/captures/lazyref.check

@@ -1,3 +1,11 @@
+-- [E007] Type Mismatch Error: tests/neg-custom-args/captures/lazyref.scala:13:2 ---------------------------------------
+13 |  (ref1, f1) => map[A, B](ref1, f1) // error // limitation
+   |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |  Found:    ? (ref1: {*} LazyRef[? A]{elem: {*} () -> box ? A}, f1: {*} (x$0: ? A) -> ? B) -> 
+   |    {f1, ref1, *} LazyRef[? B]{elem: {*} () -> box ? B}
+   |  Required: (ref: {*} LazyRef[A], f: A => B) -> {f, ref} LazyRef[B]
+   |
+   | longer explanation available when compiling with `-explain`
 -- [E007] Type Mismatch Error: tests/neg-custom-args/captures/lazyref.scala:19:28 --------------------------------------
 19 |  val ref1c: LazyRef[Int] = ref1 // error
    |                            ^^^^

tests/neg-custom-args/captures/lazyref.scala

@@ -10,7 +10,7 @@ def map[A, B](ref: {*} LazyRef[A], f: A => B): {f, ref} LazyRef[B] =
   new LazyRef(() => f(ref.elem()))
 
 def mapc[A, B]: (ref: {*} LazyRef[A], f: A => B) -> {f, ref} LazyRef[B] =
-  (ref1, f1) => map[A, B](ref1, f1)
+  (ref1, f1) => map[A, B](ref1, f1) // error // limitation
 
 def test(cap1: Cap, cap2: Cap) =
   def f(x: Int) = if cap1 == cap1 then x else 0