Even more regression tests

Closes scala#12448
Closes scala#12487
Closes scala#12160

Author: odersky

tests/neg/i12448.scala

@@ -0,0 +1,5 @@
+class A
+object Main {
+  def mkArray[T <: A]: T#AType // error // error
+  mkArray[Array]
+}

tests/neg/i12487.check

@@ -0,0 +1,4 @@
+-- [E008] Not Found Error: tests/neg/i12487.scala:19:10 ----------------------------------------------------------------
+19 |  example notCombine example  // error
+   |  ^^^^^^^^^^^^^^^^^^
+   |  value notCombine is not a member of A

tests/neg/i12487.scala

@@ -0,0 +1,21 @@
+trait A {
+  def combine(another: A): A = ???
+}
+
+trait Dsl {
+  def example: A
+}
+
+object Dsl {
+  def execute(program: (dsl: Dsl) ?=> Int): String = ???
+}
+
+def example(using a: Dsl): A = ???
+
+import Dsl._
+
+def demo = Dsl.execute {
+  // change to `combine` and it compiles
+  example notCombine example  // error
+  42
+}

tests/run/i12160.scala

@@ -0,0 +1,8 @@
+package internal:
+  object Foo:
+    inline def foo: Unit = P.s
+
+    private object P { def s = "b" }
+end internal
+
+@main def Test = internal.Foo.foo