140 lines
3.4 KiB
TypeScript
140 lines
3.4 KiB
TypeScript
// @strict: true
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// @declaration: true
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declare function isString(value: unknown): value is string;
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declare function isArrayOfStrings(value: unknown): value is string[];
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const assert: (value: unknown) => asserts value = value => {}
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declare function assertIsString(value: unknown): asserts value is string;
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declare function assertIsArrayOfStrings(value: unknown): asserts value is string[];
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declare function assertDefined<T>(value: T): asserts value is NonNullable<T>;
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function f01(x: unknown) {
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if (!!true) {
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assert(typeof x === "string");
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x.length;
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}
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if (!!true) {
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assert(x instanceof Error);
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x.message;
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}
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if (!!true) {
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assert(typeof x === "boolean" || typeof x === "number");
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x.toLocaleString;
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}
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if (!!true) {
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assert(isArrayOfStrings(x));
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x[0].length;
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}
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if (!!true) {
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assertIsArrayOfStrings(x);
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x[0].length;
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}
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if (!!true) {
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assert(x === undefined || typeof x === "string");
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x; // string | undefined
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assertDefined(x);
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x; // string
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}
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}
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function f02(x: string | undefined) {
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if (!!true) {
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assert(x);
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x.length;
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}
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if (!!true) {
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assert(x !== undefined);
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x.length;
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}
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if (!!true) {
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assertDefined(x);
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x.length;
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}
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}
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function f03(x: string | undefined, assert: (value: unknown) => asserts value) {
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assert(x);
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x.length;
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}
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namespace Debug {
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export declare function assert(value: unknown, message?: string): asserts value;
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export declare function assertDefined<T>(value: T): asserts value is NonNullable<T>;
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}
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function f10(x: string | undefined) {
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if (!!true) {
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Debug.assert(x);
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x.length;
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}
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if (!!true) {
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Debug.assert(x !== undefined);
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x.length;
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}
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if (!!true) {
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Debug.assertDefined(x);
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x.length;
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}
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}
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class Test {
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assert(value: unknown): asserts value {
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if (value) return;
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throw new Error();
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}
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isTest2(): this is Test2 {
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return this instanceof Test2;
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}
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assertIsTest2(): asserts this is Test2 {
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if (this instanceof Test2) return;
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throw new Error();
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}
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assertThis(): asserts this {
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if (!this) return;
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throw new Error();
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}
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bar() {
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this.assertThis();
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this;
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}
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foo(x: unknown) {
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this.assert(typeof x === "string");
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x.length;
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if (this.isTest2()) {
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this.z;
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}
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this.assertIsTest2();
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this.z;
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}
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}
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class Test2 extends Test {
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z = 0;
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}
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// Invalid constructs
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declare let Q1: new (x: unknown) => x is string;
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declare let Q2: new (x: boolean) => asserts x;
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declare let Q3: new (x: unknown) => asserts x is string;
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declare class Wat {
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get p1(): this is string;
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set p1(x: this is string);
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get p2(): asserts this is string;
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set p2(x: asserts this is string);
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}
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function f20(x: unknown) {
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const assert = (value: unknown): asserts value => {}
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assert(typeof x === "string"); // Error
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const a = [assert];
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a[0](typeof x === "string"); // Error
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const t1 = new Test();
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t1.assert(typeof x === "string"); // Error
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const t2: Test = new Test();
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t2.assert(typeof x === "string");
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}
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