96 lines
2 KiB
Text
96 lines
2 KiB
Text
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=== tests/cases/conformance/expressions/typeGuards/typeGuardsDefeat.ts ===
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// Also note that it is possible to defeat a type guard by calling a function that changes the
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// type of the guarded variable.
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function foo(x: number | string) {
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>foo : (x: string | number) => number
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>x : string | number
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function f() {
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>f : () => void
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x = 10;
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>x = 10 : number
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>x : string | number
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}
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if (typeof x === "string") {
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>typeof x === "string" : boolean
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>typeof x : string
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>x : string | number
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f();
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>f() : void
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>f : () => void
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return x.length; // string
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>x.length : number
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>x : string
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>length : number
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}
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else {
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return x++; // number
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>x++ : number
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>x : number
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}
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}
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function foo2(x: number | string) {
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>foo2 : (x: string | number) => number
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>x : string | number
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if (typeof x === "string") {
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>typeof x === "string" : boolean
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>typeof x : string
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>x : string | number
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return x.length; // string
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>x.length : number
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>x : string
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>length : number
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}
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else {
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(function f() {
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>(function f() { x = 10; })() : void
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>(function f() { x = 10; }) : () => void
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>function f() { x = 10; } : () => void
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>f : () => void
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x = 10;
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>x = 10 : number
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>x : string | number
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})();
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return x++; // number
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>x++ : number
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>x : number
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}
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}
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function foo3(x: number | string) {
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>foo3 : (x: string | number) => number
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>x : string | number
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if (typeof x === "string") {
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>typeof x === "string" : boolean
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>typeof x : string
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>x : string | number
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return x.length; // string
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>x.length : number
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>x : string
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>length : number
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}
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else {
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(() => {
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>(() => { x = 10; })() : void
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>(() => { x = 10; }) : () => void
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>() => { x = 10; } : () => void
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x = 10;
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>x = 10 : number
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>x : string | number
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})();
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return x++; // number
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>x++ : number
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>x : number
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}
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}
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