From 0c3221c2205f50ec3f0c069ec919f35b7aebfb5a Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 15 Oct 2018 10:24:00 -0700
Subject: [PATCH] Add regression test

---
 .../conformance/types/mapped/recursiveMappedTypes.ts  | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/tests/cases/conformance/types/mapped/recursiveMappedTypes.ts b/tests/cases/conformance/types/mapped/recursiveMappedTypes.ts
index 7a78ad9dc4a..188efa2f51a 100644
--- a/tests/cases/conformance/types/mapped/recursiveMappedTypes.ts
+++ b/tests/cases/conformance/types/mapped/recursiveMappedTypes.ts
@@ -12,4 +12,13 @@ type Recurse1 = {
 
 type Recurse2 = {
     [K in keyof Recurse1]: Recurse1[K]
-}
\ No newline at end of file
+}
+
+// Repro from #27881
+
+export type Circular<T> = {[P in keyof T]: Circular<T>};
+type tup = [number, number, number, number];
+
+function foo(arg: Circular<tup>): tup {
+  return arg;
+}