From 1bc438961579496fc9ebfe83d039afb6cdb284b0 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 24 Jan 2019 17:07:44 -0800
Subject: [PATCH] Add tests

---
 ...extuallyTypedParametersWithInitializers.ts | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 tests/cases/compiler/contextuallyTypedParametersWithInitializers.ts

diff --git a/tests/cases/compiler/contextuallyTypedParametersWithInitializers.ts b/tests/cases/compiler/contextuallyTypedParametersWithInitializers.ts
new file mode 100644
index 00000000000..e68be5b7bfd
--- /dev/null
+++ b/tests/cases/compiler/contextuallyTypedParametersWithInitializers.ts
@@ -0,0 +1,32 @@
+// @strict: true
+// @declaration: true
+
+declare function id1<T>(input: T): T;
+declare function id2<T extends (x: any) => any>(input: T): T;
+declare function id3<T extends (x: { foo: any }) => any>(input: T): T;
+declare function id4<T extends (x: { foo?: number }) => any>(input: T): T;
+declare function id5<T extends (x?: number) => any>(input: T): T;
+
+const f10 = function ({ foo = 42 }) { return foo };
+const f11 = id1(function ({ foo = 42 }) { return foo });  // Implicit any error
+const f12 = id2(function ({ foo = 42 }) { return foo });
+const f13 = id3(function ({ foo = 42 }) { return foo });
+const f14 = id4(function ({ foo = 42 }) { return foo });
+
+const f20 = function (foo = 42) { return foo };
+const f21 = id1(function (foo = 42) { return foo });  // Implicit any error
+const f22 = id2(function (foo = 42) { return foo });
+const f25 = id5(function (foo = 42) { return foo });
+
+// Repro from #28816
+
+function id<T>(input: T): T { return input }
+
+function getFoo ({ foo = 42 }) {
+  return foo;
+}
+
+const newGetFoo = id(getFoo);
+const newGetFoo2 = id(function getFoo ({ foo = 42 }) {
+  return foo;
+});