From 290eff9722a2f8a0f267c30a3b3e78a16489b985 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 30 Nov 2018 16:28:21 -0800
Subject: [PATCH] Add regression test

---
 .../compiler/controlFlowDestructuringLoop.ts  | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 tests/cases/compiler/controlFlowDestructuringLoop.ts

diff --git a/tests/cases/compiler/controlFlowDestructuringLoop.ts b/tests/cases/compiler/controlFlowDestructuringLoop.ts
new file mode 100644
index 0000000000..bf3a68cb2d
--- /dev/null
+++ b/tests/cases/compiler/controlFlowDestructuringLoop.ts
@@ -0,0 +1,24 @@
+// @strict: true
+
+// Repro from #28758
+
+interface NumVal { val: number; }
+interface StrVal { val: string; }
+type Val = NumVal | StrVal;
+
+function isNumVal(x: Val): x is NumVal {
+    return typeof x.val === 'number';
+}
+
+function foo(things: Val[]): void {
+    for (const thing of things) {
+        if (isNumVal(thing)) {
+            const { val } = thing;
+            val.toFixed(2);
+        }
+        else {
+            const { val } = thing;
+            val.length;
+        }
+    }
+}
\ No newline at end of file