From 9d2a2c96344011a9f3db5ee85dc2cbb61c059b83 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 6 Jun 2019 13:33:36 -0700
Subject: [PATCH] Add tests

---
 .../propertyAccess/propertyAccessWidening.ts  | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 tests/cases/conformance/expressions/propertyAccess/propertyAccessWidening.ts

diff --git a/tests/cases/conformance/expressions/propertyAccess/propertyAccessWidening.ts b/tests/cases/conformance/expressions/propertyAccess/propertyAccessWidening.ts
new file mode 100644
index 00000000000..ddcad3f57c9
--- /dev/null
+++ b/tests/cases/conformance/expressions/propertyAccess/propertyAccessWidening.ts
@@ -0,0 +1,22 @@
+// @strict: true
+
+// Repro from #31762
+
+function g1(headerNames: any) {
+    let t = [{ hasLineBreak: false, cells: [] }];
+    const table = [{cells: headerNames }].concat(t);
+}
+
+function g2(headerNames: any) {
+    let t = [{ hasLineBreak: false, cells: [] }];
+    const table = [{cells: headerNames }]["concat"](t);
+}
+
+// Object in property or element access is widened when target of assignment
+
+function foo(options?: { a: string, b: number }) {
+    let x1 = (options || {}).a;     // Object type not widened
+    let x2 = (options || {})["a"];  // Object type not widened
+    (options || {}).a = 1;          // Object type widened, error
+    (options || {})["a"] = 1;       // Object type widened, error
+}