Add test for Tree | (Context => Tree)

Author: liufengyun

compiler/src/dotty/tools/dotc/core/Annotations.scala

@@ -86,7 +86,7 @@ object Annotations {
       myTree.asInstanceOf[Tree]
 
     override def isEvaluating: Boolean = myTree == null
-    override def isEvaluated: Boolean = myTree.isInstanceOf[Tree]
+    override def isEvaluated: Boolean = myTree.isInstanceOf[Tree @unchecked]
   }
 
   /** An annotation indicating the body of a right-hand side,
@@ -119,7 +119,7 @@ object Annotations {
       myTree.asInstanceOf[Tree]
 
     override def isEvaluating: Boolean = myTree == null
-    override def isEvaluated: Boolean = myTree.isInstanceOf[Tree]
+    override def isEvaluated: Boolean = myTree.isInstanceOf[Tree @unchecked]
   }
 
   object LazyBodyAnnotation {

tests/neg-custom-args/isInstanceOf/or-type-trees.scala

@@ -1,13 +1,38 @@
-trait Tree
-trait Context
-
-def foo(myTree: Tree | (Context => Tree)) =
-  println(myTree.isInstanceOf[Tree])
-  myTree match
-    case treeFn: (Context => Tree) =>  // error
-    case _ =>
-
-def bar(myTree: Tree | (Context => Tree)) =
-  myTree match
-    case treeFn: (_ => _) =>       // ok
-    case _ =>
+object Test1 {
+  trait Tree
+  trait Context
+
+  def foo1(myTree: Tree | (Context => Tree)) =
+    println(myTree.isInstanceOf[Tree])
+
+  def foo2(myTree: Tree | (Context => Tree)) =
+    myTree match
+      case treeFn: (Context => Tree) =>  // error
+      case _ =>
+
+  def foo3(myTree: Tree | (Context => Tree)) =
+    myTree match
+      case treeFn: (_ => _) =>       // ok
+      case _ =>
+}
+
+object Test2 {
+  trait Tree[-T]
+  trait Context
+
+  trait Type
+
+  def foo1(myTree: Tree[Type] | (Context => Tree[Type])) =
+    println(myTree.isInstanceOf[Tree[Type]])   // error
+    /* class DummyTree extends Tree[Nothing] with (Context => Tree[Type]) */
+
+  def foo2(myTree: Tree[Type] | (Context => Tree[Type])) =
+    myTree match
+      case treeFn: (Context => Tree[Type]) =>  // error
+      case _ =>
+
+  def foo3(myTree: Tree[Type] | (Context => Tree[Type])) =
+    myTree match
+      case treeFn: (_ => _) =>       // ok
+      case _ =>
+}