From 238177657fcd10526010d525093eb3b58d128b0d Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 8 May 2018 09:42:21 -0700
Subject: [PATCH] Add regression test

---
 .../conformance/types/keyof/keyofAndIndexedAccess.ts      | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
index 83687e8c872..07aa3c1994f 100644
--- a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
+++ b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess.ts
@@ -629,3 +629,11 @@ class Unbounded<T> {
         let y: {} | undefined | null = x;
     }
 }
+
+// Repro from #23940
+
+interface I7 {
+    x: any;
+}
+type Foo7<T extends number> = T;
+declare function f7<K extends keyof I7>(type: K): Foo7<I7[K]>;