From 2c951b3ca99751c98a23d1bb707803264f0f6bdf Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Sat, 13 Apr 2019 08:24:27 -1000
Subject: [PATCH] Add regression test

---
 .../types/intersection/intersectionWithUnionConstraint.ts    | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/cases/conformance/types/intersection/intersectionWithUnionConstraint.ts b/tests/cases/conformance/types/intersection/intersectionWithUnionConstraint.ts
index 278d72595cd..2a756788f6f 100644
--- a/tests/cases/conformance/types/intersection/intersectionWithUnionConstraint.ts
+++ b/tests/cases/conformance/types/intersection/intersectionWithUnionConstraint.ts
@@ -34,3 +34,8 @@ type Example<T, U> = { [K in keyof T]: K extends keyof U ? UnexpectedError<K> :
 
 type UnexpectedError<T extends PropertyKey> = T
 type NoErrorHere<T extends PropertyKey> = T
+
+// Repro from #30331
+
+type a<T> = T extends Array<infer U> ? U : never;
+type b<T> = { [K in a<T> & keyof T ]: 42 };