diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 1bc75e4fec20..c9930e036559 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -5287,17 +5287,6 @@ object Types {
     protected def mapClassInfo(tp: ClassInfo): Type =
       derivedClassInfo(tp, this(tp.prefix))
 
-    /** A version of mapClassInfo which also maps parents and self type */
-    protected def mapFullClassInfo(tp: ClassInfo): ClassInfo =
-      tp.derivedClassInfo(
-        prefix = this(tp.prefix),
-        declaredParents = tp.declaredParents.mapConserve(this),
-        selfInfo = tp.selfInfo match {
-          case tp: Type => this(tp)
-          case sym => sym
-        }
-      )
-
     def andThen(f: Type => Type): TypeMap = new TypeMap {
       override def stopAtStatic = thisMap.stopAtStatic
       def apply(tp: Type) = f(thisMap(tp))
@@ -5308,7 +5297,7 @@ object Types {
   abstract class DeepTypeMap(using Context) extends TypeMap {
     override def mapClassInfo(tp: ClassInfo): ClassInfo = {
       val prefix1 = this(tp.prefix)
-      val parents1 = tp.parents mapConserve this
+      val parents1 = tp.declaredParents mapConserve this
       val selfInfo1: TypeOrSymbol = tp.selfInfo match {
         case selfInfo: Type => this(selfInfo)
         case selfInfo => selfInfo
diff --git a/compiler/src/dotty/tools/dotc/typer/Inliner.scala b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
index 81b26246ff85..527928a6a462 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inliner.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
@@ -712,7 +712,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(using Context) {
     // the owner from the inlined method to the current owner.
     val inliner = new TreeTypeMap(
       typeMap =
-        new TypeMap {
+        new DeepTypeMap {
           def apply(t: Type) = t match {
             case t: ThisType => thisProxy.getOrElse(t.cls, t)
             case t: TypeRef => paramProxy.getOrElse(t, mapOver(t))
@@ -721,7 +721,6 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(using Context) {
               else paramProxy.getOrElse(t, mapOver(t))
             case t => mapOver(t)
           }
-          override def mapClassInfo(tp: ClassInfo) = mapFullClassInfo(tp)
         },
       treeMap = {
         case tree: This =>