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// @target: es6
// @noEmit: true
// @allowJs: true
// @checkJs: true
// @strictNullChecks: true
// @Filename: controlFlowInstanceof.ts
// Repros from #10167
function f1(s: Set<string> | Set<number>) {
s = new Set<number>();
s; // Set<number>
if (s instanceof Set) {
s; // Set<number>
}
s; // Set<number>
s.add(42);
}
function f2(s: Set<string> | Set<number>) {
s = new Set<number>();
s; // Set<number>
if (s instanceof Promise) {
s; // Set<number> & Promise<any>
}
s; // Set<number>
s.add(42);
}
function f3(s: Set<string> | Set<number>) {
s; // Set<string> | Set<number>
if (s instanceof Set) {
s; // Set<string> | Set<number>
}
else {
s; // never
}
}
function f4(s: Set<string> | Set<number>) {
s = new Set<number>();
s; // Set<number>
if (s instanceof Set) {
s; // Set<number>
}
else {
s; // never
}
}
// More tests
class A { a: string }
class B extends A { b: string }
class C extends A { c: string }
function foo(x: A | undefined) {
x; // A | undefined
if (x instanceof B || x instanceof C) {
x; // B | C
}
x; // A | undefined
if (x instanceof B && x instanceof C) {
x; // B & C
}
x; // A | undefined
if (!x) {
return;
}
x; // A
if (x instanceof B) {
x; // B
if (x instanceof C) {
x; // B & C
}
else {
x; // B
}
x; // B
}
else {
x; // A
}
x; // A
}
// X is neither assignable to Y nor a subtype of Y
// Y is assignable to X, but not a subtype of X
interface X {
x?: string;
}
class Y {
y: string;
}
function goo(x: X) {
x;
if (x instanceof Y) {
x.y;
}
x;
}
// Repro from #27282
declare const x: (() => void)|null;
declare const ctor: Function;
if (x instanceof ctor) {
x();
}
// Repro from #27550 (based on uglify code)
// @Filename: uglify.js
/** @constructor */
function AtTop(val) { this.val = val }
/** @type {*} */
var v = 1;
if (v instanceof AtTop) {
v.val
}
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