Add test

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -1157,7 +1157,7 @@ object Semantic:
         if !isHotSegment then
           for member <- klass.info.decls do
             if member.isClass then
-              val error = PromoteError(msg + " Promotion cancelled as the value contains inner classes.", trace.toVector)
+              val error = PromoteError("Promotion cancelled as the value contains inner " + member.show + ".", Vector.empty)
               reporter.report(error)
             else if !member.isType && !member.isConstructor  && !member.is(Flags.Deferred) then
               given Trace = Trace.empty

tests/init/neg/promotion-segment3.check

@@ -0,0 +1,12 @@
+-- Error: tests/init/neg/promotion-segment3.scala:9:6 ------------------------------------------------------------------
+9 |  bar(new B)  // error
+  |      ^^^^^
+  |      Cannot prove the method argument is hot. Only hot values are safe to leak.
+  |      Found = Warm[class B] { outer = ThisRef[class A] }. Calling trace:
+  |      -> class A:	[ promotion-segment3.scala:2 ]
+  |         ^
+  |      -> bar(new B)  // error	[ promotion-segment3.scala:9 ]
+  |             ^^^^^
+  |
+  |      Promoting the value to hot failed due to the following problem:
+  |      Promotion cancelled as the value contains inner class C.

tests/init/neg/promotion-segment3.scala

@@ -0,0 +1,11 @@
+
+class A:
+  class B:
+    class C:
+      def foo(): Int = m
+
+  def bar(b: B) = new b.C().foo()
+
+  bar(new B)  // error
+
+  val m = 10