diff --git a/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala b/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
index 7d2d95aa9601..def27742c189 100644
--- a/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
+++ b/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
@@ -405,21 +405,19 @@ class TreePickler(pickler: TastyPickler, attributes: Attributes) {
               pickleType(tp)
           }
         case This(qual) =>
-          // This may be needed when pickling a `This` inside a capture set. See #19662 and #19859.
-          // In this case, we pickle the tree as null.asInstanceOf[tree.tpe].
-          // Since the pickled tree is not the same as the input, special handling is needed
-          // in the tree printer when testing the pickler. See [[PlainPrinter#homogenize]].
-          inline def pickleCapturedThis =
-            pickleTree(Literal(Constant(null)).cast(tree.tpe).withSpan(tree.span))
           if (qual.isEmpty)
             if tree.tpe.isSingleton then pickleType(tree.tpe)
-            else pickleCapturedThis
-          else
-            tree.tpe match
-              case ThisType(tref) =>
-                writeByte(QUALTHIS)
-                pickleTree(qual.withType(tref))
-              case _ => pickleCapturedThis
+            else
+              // This may happen when pickling a `This` inside a capture set. See #19662.
+              // In this case, we pickle the tree as null.asInstanceOf[tree.tpe].
+              // Since the pickled tree is not the same as the input, special handling is needed
+              // in the tree printer when testing the pickler. See [[PlainPrinter#homogenize]].
+              pickleTree(Literal(Constant(null)).cast(tree.tpe).withSpan(tree.span))
+          else {
+            writeByte(QUALTHIS)
+            val ThisType(tref) = tree.tpe: @unchecked
+            pickleTree(qual.withType(tref))
+          }
         case Select(qual, name) =>
           name match {
             case OuterSelectName(_, levels) =>