From 23162c2638444f3474d3f93529c12aa786303abd Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 13 Feb 2018 06:48:03 -0800
Subject: [PATCH] Add tests

---
 .../conformance/types/mapped/mappedTypes6.ts  | 127 ++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 tests/cases/conformance/types/mapped/mappedTypes6.ts

diff --git a/tests/cases/conformance/types/mapped/mappedTypes6.ts b/tests/cases/conformance/types/mapped/mappedTypes6.ts
new file mode 100644
index 0000000000..b3beef7684
--- /dev/null
+++ b/tests/cases/conformance/types/mapped/mappedTypes6.ts
@@ -0,0 +1,127 @@
+// @strict: true
+// @declaration: true
+
+type T00<T> = { [P in keyof T]: T[P] };
+type T01<T> = { [P in keyof T]?: T[P] };
+type T02<T> = { [P in keyof T]+?: T[P] };
+type T03<T> = { [P in keyof T]-?: T[P] };
+
+type T04<T> = { readonly [P in keyof T]: T[P] };
+type T05<T> = { readonly [P in keyof T]?: T[P] };
+type T06<T> = { readonly [P in keyof T]+?: T[P] };
+type T07<T> = { readonly [P in keyof T]-?: T[P] };
+
+type T08<T> = { +readonly [P in keyof T]: T[P] };
+type T09<T> = { +readonly [P in keyof T]?: T[P] };
+type T10<T> = { +readonly [P in keyof T]+?: T[P] };
+type T11<T> = { +readonly [P in keyof T]-?: T[P] };
+
+type T12<T> = { -readonly [P in keyof T]: T[P] };
+type T13<T> = { -readonly [P in keyof T]?: T[P] };
+type T14<T> = { -readonly [P in keyof T]+?: T[P] };
+type T15<T> = { -readonly [P in keyof T]-?: T[P] };
+
+function f1<T>(x: Required<T>, y: T, z: Partial<T>) {
+    x = x;
+    x = y;  // Error
+    x = z;  // Error
+    y = x;
+    y = y;
+    y = z;  // Error
+    z = x;
+    z = y;
+    z = z;
+}
+
+type Denullified<T> = { [P in keyof T]-?: NonNullable<T[P]> };
+
+function f2<T>(w: Denullified<T>, x: Required<T>, y: T, z: Partial<T>) {
+    w = w;
+    w = x;  // Error
+    w = y;  // Error
+    w = z;  // Error
+    x = w;
+    x = x;
+    x = y;  // Error
+    x = z;  // Error
+    y = w;
+    y = x;
+    y = y;
+    y = z;  // Error
+    z = w;
+    z = x;
+    z = y;
+    z = z;
+}
+
+
+function f3<T>(w: Denullified<T>, x: Required<T>, y: T, z: Partial<T>) {
+    w = {};  // Error
+    x = {};  // Error
+    y = {};  // Error
+    z = {};
+}
+
+type Readwrite<T> = {
+    -readonly [P in keyof T]: T[P];
+}
+
+function f10<T>(x: Readonly<T>, y: T, z: Readwrite<T>) {
+    x = x;
+    x = y;
+    x = z;
+    y = x;
+    y = y;
+    y = z;
+    z = x;
+    z = y;
+    z = z;
+}
+
+type Foo = {
+    a: number;
+    b: number | undefined;
+    c?: number;
+    d?: number | undefined;
+}
+
+declare let x1: Foo;
+
+x1.a;  // number
+x1.b;  // number | undefined
+x1.c;  // number | undefined
+x1.d;  // number | undefined
+
+x1 = { a: 1 };  // Error
+x1 = { a: 1, b: 1 };
+x1 = { a: 1, b: 1, c: 1 };
+x1 = { a: 1, b: 1, c: 1, d: 1 };
+
+declare let x2: Required<Foo>;
+
+x1.a;  // number
+x1.b;  // number | undefined
+x1.c;  // number
+x1.d;  // number
+
+x2 = { a: 1 };  // Error
+x2 = { a: 1, b: 1 };  // Error
+x2 = { a: 1, b: 1, c: 1 };  // Error
+x2 = { a: 1, b: 1, c: 1, d: 1 };
+
+type Bar = {
+    a: number;
+    readonly b: number;
+}
+
+declare let x3: Bar;
+x3.a = 1;
+x3.b = 1;  // Error
+
+declare let x4: Readonly<Bar>;
+x4.a = 1;  // Error
+x4.b = 1;  // Error
+
+declare let x5: Readwrite<Bar>;
+x5.a = 1;
+x5.b = 1;