From 739acee1c95d32ed4eca274ea90b47a32adc1742 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 4 Apr 2019 16:30:26 -0700
Subject: [PATCH] Add tests

---
 .../types/keyof/keyofAndIndexedAccess2.ts     | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts

diff --git a/tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts
new file mode 100644
index 00000000000..ee724dc1251
--- /dev/null
+++ b/tests/cases/conformance/types/keyof/keyofAndIndexedAccess2.ts
@@ -0,0 +1,107 @@
+// @strict: true
+// @target: esnext
+
+function f1(obj: { a: number, b: 0 | 1, c: string }, k0: 'a', k1: 'a' | 'b', k2: 'a' | 'b' | 'c') {
+    obj[k0] = 1;
+    obj[k0] = 2;
+    obj[k0] = 'x';  // Error
+    obj[k1] = 1;
+    obj[k1] = 2;    // Error
+    obj[k1] = 'x';  // Error
+    obj[k2] = 1;    // Error
+    obj[k2] = 2;    // Error
+    obj[k2] = 'x';  // Error
+}
+
+function f2<T extends { [key: string]: number }>(a: { x: number, y: number }, b: { [key: string]: number }, c: T, k: keyof T) {
+    a = b;  // Error, index signature in source doesn't imply properties are present
+    a = c;  // Error, index signature in source doesn't imply properties are present
+    b = a;
+    b = c;
+    c = a;  // Error, constraint on target doesn't imply any properties or signatures
+    c = b;  // Error, constraint on target doesn't imply any properties or signatures
+    a.x;
+    b.x;
+    c.x;
+    c[k];
+    a.x = 1;
+    b.x = 1;
+    c.x = 1;  // Error, cannot write to index signature through constraint
+    c[k] = 1; // Error, cannot write to index signature through constraint
+}
+
+function f3<K extends string>(a: { [P in K]: number }, b: { [key: string]: number }, k: K) {
+    a = b;  // Error, index signature doesn't imply properties are present
+    b = a;
+    a[k];
+    a[k] = 1;
+}
+
+function f4<K extends string>(a: { [key: string]: number }[K], b: number) {
+  a = b;
+  b = a;
+}
+
+type Item = { a: string, b: number };
+
+function f10<T extends Item, K extends keyof T>(obj: T, k1: string, k2: keyof Item, k3: keyof T, k4: K) {
+  obj[k1] = 123;  // Error
+  obj[k2] = 123;  // Error
+  obj[k3] = 123;  // Error
+  obj[k4] = 123;  // Error
+}
+
+type Dict = Record<string, number>;
+
+function f11<K extends keyof Dict>(obj: Dict, k1: keyof Dict, k2: K) {
+  obj.foo = 123;
+  obj[k1] = 123;
+  obj[k2] = 123;
+}
+
+function f12<T extends Readonly<Dict>, K extends keyof T>(obj: T, k1: keyof Dict, k2: keyof T, k3: K) {
+  obj.foo = 123;  // Error
+  obj[k1] = 123;  // Error
+  obj[k2] = 123;  // Error
+  obj[k3] = 123;  // Error
+}
+
+// Repro from #27895
+
+export interface Entity {
+    id: number | string;
+}
+
+export type IdOf<E extends Entity> = E['id'];
+
+export interface EntityState<E extends Entity> {
+    ids: IdOf<E>[];
+    entities: { [key: string]: E, [key: number]: E };
+}
+
+
+export function getAllEntities<E extends Entity>(state: EntityState<E>): E[] {
+    const { ids, entities } = state;
+    return ids.map(id => entities[id]);
+}
+
+export function getEntity<E extends Entity>(id: IdOf<E>, state: EntityState<E>): E | undefined {
+    const { ids, entities } = state;
+
+    if (!ids.includes(id)) {
+        return undefined;
+    }
+
+    return entities[id];
+}
+
+// Repro from #30603
+
+interface Type {
+    a: 123;
+    b: "some string";
+}
+
+function get123<K extends keyof Type>(): Type[K] {
+    return 123;  // Error
+}