From 22c934a065d56f0578a58b6258fcc8775ffd4cf0 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 4 Mar 2019 11:07:02 -0800
Subject: [PATCH] Add tests

---
 .../compiler/genericFunctionInference1.ts     | 133 ++++++++++++++++--
 1 file changed, 119 insertions(+), 14 deletions(-)

diff --git a/tests/cases/compiler/genericFunctionInference1.ts b/tests/cases/compiler/genericFunctionInference1.ts
index c5416f32bda..f2a71ca7f02 100644
--- a/tests/cases/compiler/genericFunctionInference1.ts
+++ b/tests/cases/compiler/genericFunctionInference1.ts
@@ -7,24 +7,129 @@ declare function pipe<A extends any[], B, C, D>(ab: (...args: A) => B, bc: (b: B
 
 declare function list<T>(a: T): T[];
 declare function box<V>(x: V): { value: V };
+declare function foo<T extends { value: T }>(x: T): T;
 
 const f00 = pipe(list);
 const f01 = pipe(list, box);
-const f02 = pipe(x => list(x), box);
-const f03 = pipe(list, x => box(x));
-const f04 = pipe(x => list(x), x => box(x))
-const f05 = pipe(list, pipe(box));
-const f06 = pipe(x => list(x), pipe(box));
-const f07 = pipe(x => list(x), pipe(x => box(x)));
+const f02 = pipe(box, list);
+const f03 = pipe(x => list(x), box);
+const f04 = pipe(list, x => box(x));
+const f05 = pipe(x => list(x), x => box(x))
+const f06 = pipe(list, pipe(box));
+const f07 = pipe(x => list(x), pipe(box));
+const f08 = pipe(x => list(x), pipe(x => box(x)));
+const f09 = pipe(list, x => x.length);
+const f10 = pipe(foo);
+const f11 = pipe(foo, foo);
 
-const f10: <T>(x: T) => T[] = pipe(list);
-const f11: <T>(x: T) => { value: T[] } = pipe(list, box);
-const f12: <T>(x: T) => { value: T[] } = pipe(x => list(x), box);
-const f13: <T>(x: T) => { value: T[] } = pipe(list, x => box(x));
-const f14: <T>(x: T) => { value: T[] } = pipe(x => list(x), x => box(x))
-const f15: <T>(x: T) => { value: T[] } = pipe(list, pipe(box));
-const f16: <T>(x: T) => { value: T[] } = pipe(x => list(x), pipe(box));
-const f17: <T>(x: T) => { value: T[] } = pipe(x => list(x), pipe(x => box(x)));
+const g00: <T>(x: T) => T[] = pipe(list);
+const g01: <T>(x: T) => { value: T[] } = pipe(list, box);
+const g02: <T>(x: T) => { value: T }[] = pipe(box, list);
+const g03: <T>(x: T) => { value: T[] } = pipe(x => list(x), box);
+const g04: <T>(x: T) => { value: T[] } = pipe(list, x => box(x));
+const g05: <T>(x: T) => { value: T[] } = pipe(x => list(x), x => box(x))
+const g06: <T>(x: T) => { value: T[] } = pipe(list, pipe(box));
+const g07: <T>(x: T) => { value: T[] } = pipe(x => list(x), pipe(box));
+const g08: <T>(x: T) => { value: T[] } = pipe(x => list(x), pipe(x => box(x)));
+const g09: <T>(x: T) => number = pipe(list, x => x.length);
+const g10: <T extends { value: T }>(x: T) => T = pipe(foo);
+const g12: <T extends { value: T }>(x: T) => T = pipe(foo, foo);
+
+declare function pipe2<A, B, C, D>(ab: (a: A) => B, cd: (c: C) => D): (a: [A, C]) => [B, D];
+
+const f20 = pipe2(list, box);
+const f21 = pipe2(box, list);
+const f22 = pipe2(list, list);
+const f23 = pipe2(box, box);
+const f24 = pipe2(f20, f20);
+const f25 = pipe2(foo, foo);
+const f26 = pipe2(f25, f25);
+
+declare function pipe3<A, B, C>(ab: (a: A) => B, ac: (a: A) => C): (a: A) => [B, C];
+
+const f30 = pipe3(list, box);
+const f31 = pipe3(box, list);
+const f32 = pipe3(list, list);
+
+declare function pipe4<A, B, C>(funcs: [(a: A) => B, (b: B) => C]): (a: A) => C;
+
+const f40 = pipe4([list, box]);
+const f41 = pipe4([box, list]);
+
+declare function pipe5<A, B>(f: (a: A) => B): { f: (a: A) => B };
+
+const f50 = pipe5(list);  // No higher order inference
+
+// #417
+
+function mirror<A, B>(f: (a: A) => B): (a: A) => B { return f; }
+var identityM = mirror(identity);
+
+var x = 1;
+var y = identity(x);
+var z = identityM(x);
+
+// #3038
+
+export function keyOf<a>(value: { key: a; }): a {
+    return value.key;
+}
+export interface Data {
+    key: number;
+    value: Date;
+}
+
+var data: Data[] = [];
+
+declare function toKeys<a>(values: a[], toKey: (value: a) => string): string[];
+
+toKeys(data, keyOf);  // Error
+
+// #9366
+
+function flip<a, b, c>(f: (a: a, b: b) => c): (b: b, a: a) => c {
+  return (b: b, a: a) => f(a, b);
+}
+function zip<T, U>(x: T, y: U): [T, U] {
+  return [x, y];
+}
+
+var expected: <T, U>(y: U, x: T) => [T, U] = flip(zip);
+var actual = flip(zip);
+
+// #9366
+
+const map = <T, U>(transform: (t: T) => U) =>
+    (arr: T[]) => arr.map(transform)
+
+const identityStr = (t: string) => t;
+
+const arr: string[] = map(identityStr)(['a']);
+const arr1: string[] = map(identity)(['a']);
+
+// #9949
+
+function of2<a, b>(one: a, two: b): [a, b] {
+    return [one, two];
+}
+
+const flipped = flip(of2);
+
+// #29904.1
+
+type Component<P> = (props: P) => {};
+
+declare const myHoc1: <P>(C: Component<P>) => Component<P>;
+declare const myHoc2: <P>(C: Component<P>) => Component<P>;
+
+declare const MyComponent1: Component<{ foo: 1 }>;
+
+const enhance = pipe(
+    myHoc1,
+    myHoc2,
+);
+
+const MyComponent2 = enhance(MyComponent1);
 
 // #29904.2