From f2896413eff7413a4786d92a2d4aba57ee366150 Mon Sep 17 00:00:00 2001
From: Yichen Xu <yichen.x@outlook.com>
Date: Wed, 27 Mar 2024 15:19:15 +0100
Subject: [PATCH] Fix the mapping of term-dependent annotations

---
 compiler/src/dotty/tools/dotc/core/Annotations.scala | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/core/Annotations.scala b/compiler/src/dotty/tools/dotc/core/Annotations.scala
index 45dba97a79f7..8ff90d3ca9bc 100644
--- a/compiler/src/dotty/tools/dotc/core/Annotations.scala
+++ b/compiler/src/dotty/tools/dotc/core/Annotations.scala
@@ -7,6 +7,7 @@ import ast.tpd, tpd.*
 import util.Spans.Span
 import printing.{Showable, Printer}
 import printing.Texts.Text
+import cc.isRetainsLike
 
 import scala.annotation.internal.sharable
 
@@ -65,7 +66,7 @@ object Annotations {
               foldOver(if tp1 frozen_=:= tree.tpe then x else tp1, tree)
         val diff = findDiff(NoType, args)
         if tm.isRange(diff) then EmptyAnnotation
-        else if diff.exists then derivedAnnotation(tm.mapOver(tree))
+        else if diff.exists || symbol.isRetainsLike then derivedAnnotation(tm.mapOver(tree))
         else this
 
     /** Does this annotation refer to a parameter of `tl`? */
@@ -73,9 +74,13 @@ object Annotations {
       val args = arguments
       if args.isEmpty then false
       else tree.existsSubTree:
-        case id: (Ident | This) => id.tpe.stripped match
+        case id: Ident => id.tpe.stripped match
           case TermParamRef(tl1, _) => tl eq tl1
           case _ => false
+        case ref: This => ref.tpe match
+          case TermParamRef(tl1, _) => tl eq tl1
+          case AnnotatedType(tp1, annot1) => annot1.refersToParamOf(tl)
+          case _ => false
         case _ => false
 
     /** A string representation of the annotation. Overridden in BodyAnnotation.