From 8410a36f9979a7d8caf78527c6879aab2d86d0d2 Mon Sep 17 00:00:00 2001
From: Yichen Xu <yichen.x@outlook.com>
Date: Tue, 14 Nov 2023 02:31:23 +0100
Subject: [PATCH 1/2] Reset comparersInUse

---
 compiler/src/dotty/tools/dotc/core/Contexts.scala | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compiler/src/dotty/tools/dotc/core/Contexts.scala b/compiler/src/dotty/tools/dotc/core/Contexts.scala
index c575f7bc72f7..dec73f7243e8 100644
--- a/compiler/src/dotty/tools/dotc/core/Contexts.scala
+++ b/compiler/src/dotty/tools/dotc/core/Contexts.scala
@@ -1063,6 +1063,7 @@ object Contexts {
       sources.clear()
       files.clear()
       comparers.clear()  // forces re-evaluation of top and bottom classes in TypeComparer
+      comparersInUse = 0
 
     // Test that access is single threaded
 

From 44c96748887fe47ac8df55069639154373cb7819 Mon Sep 17 00:00:00 2001
From: Yichen Xu <yichen.x@outlook.com>
Date: Tue, 14 Nov 2023 02:31:51 +0100
Subject: [PATCH 2/2] Add test case for #18855

---
 tests/pos-macros/i18855/invoc.scala | 3 +++
 tests/pos-macros/i18855/macro.scala | 7 +++++++
 2 files changed, 10 insertions(+)
 create mode 100644 tests/pos-macros/i18855/invoc.scala
 create mode 100644 tests/pos-macros/i18855/macro.scala

diff --git a/tests/pos-macros/i18855/invoc.scala b/tests/pos-macros/i18855/invoc.scala
new file mode 100644
index 000000000000..2923abd4836a
--- /dev/null
+++ b/tests/pos-macros/i18855/invoc.scala
@@ -0,0 +1,3 @@
+import scala.language.experimental.captureChecking
+val x = run()
+
diff --git a/tests/pos-macros/i18855/macro.scala b/tests/pos-macros/i18855/macro.scala
new file mode 100644
index 000000000000..1c0ee28effbe
--- /dev/null
+++ b/tests/pos-macros/i18855/macro.scala
@@ -0,0 +1,7 @@
+import scala.quoted.*
+import scala.language.experimental.captureChecking
+
+def impl()(using Quotes): Expr[Unit] = '{()}
+inline def run(): Unit = ${impl()}
+
+