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weswighamweswigham
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Primitives should not be instanceof... anything (#27402)
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5 files changed

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5 files changed

+165
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lines changed

‎src/compiler/checker.ts

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@@ -10595,6 +10595,7 @@ namespace ts {
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function isTypeDerivedFrom(source: Type, target: Type): boolean {
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return source.flags & TypeFlags.Union ? every((<UnionType>source).types, t => isTypeDerivedFrom(t, target)) :
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target.flags & TypeFlags.Union ? some((<UnionType>target).types, t => isTypeDerivedFrom(source, t)) :
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source.flags & TypeFlags.Primitive && !(target.flags & TypeFlags.Primitive) ? false :
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source.flags & TypeFlags.InstantiableNonPrimitive ? isTypeDerivedFrom(getBaseConstraintOfType(source) || emptyObjectType, target) :
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target === globalObjectType || target === globalFunctionType ? isTypeSubtypeOf(source, target) :
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hasBaseType(source, getTargetType(target));

‎tests/baselines/reference/controlFlowInstanceOfGuardPrimitives.js

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//// [controlFlowInstanceOfGuardPrimitives.ts]
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function distinguish(thing: string | number | Date) {
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if (thing instanceof Object) {
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console.log("Aha!! It's a Date in " + thing.getFullYear());
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} else if (typeof thing === 'string') {
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console.log("Aha!! It's a string of length " + thing.length);
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} else {
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console.log("Aha!! It's the number " + thing.toPrecision(3));
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}
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}
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distinguish(new Date());
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distinguish("beef");
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distinguish(3.14159265);
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//// [controlFlowInstanceOfGuardPrimitives.js]
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function distinguish(thing) {
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if (thing instanceof Object) {
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console.log("Aha!! It's a Date in " + thing.getFullYear());
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}
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else if (typeof thing === 'string') {
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console.log("Aha!! It's a string of length " + thing.length);
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}
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else {
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console.log("Aha!! It's the number " + thing.toPrecision(3));
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}
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}
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distinguish(new Date());
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distinguish("beef");
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distinguish(3.14159265);

‎tests/baselines/reference/controlFlowInstanceOfGuardPrimitives.symbols

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=== tests/cases/conformance/controlFlow/controlFlowInstanceOfGuardPrimitives.ts ===
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function distinguish(thing: string | number | Date) {
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>distinguish : Symbol(distinguish, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 0))
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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>Date : Symbol(Date, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.scripthost.d.ts, --, --))
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if (thing instanceof Object) {
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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>Object : Symbol(Object, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
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console.log("Aha!! It's a Date in " + thing.getFullYear());
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>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
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>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>thing.getFullYear : Symbol(Date.getFullYear, Decl(lib.es5.d.ts, --, --))
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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>getFullYear : Symbol(Date.getFullYear, Decl(lib.es5.d.ts, --, --))
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} else if (typeof thing === 'string') {
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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console.log("Aha!! It's a string of length " + thing.length);
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>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
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>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>thing.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
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} else {
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console.log("Aha!! It's the number " + thing.toPrecision(3));
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>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
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>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
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>thing.toPrecision : Symbol(Number.toPrecision, Decl(lib.es5.d.ts, --, --))
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>thing : Symbol(thing, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 21))
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>toPrecision : Symbol(Number.toPrecision, Decl(lib.es5.d.ts, --, --))
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}
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}
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distinguish(new Date());
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>distinguish : Symbol(distinguish, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 0))
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>Date : Symbol(Date, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.scripthost.d.ts, --, --))
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distinguish("beef");
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>distinguish : Symbol(distinguish, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 0))
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distinguish(3.14159265);
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>distinguish : Symbol(distinguish, Decl(controlFlowInstanceOfGuardPrimitives.ts, 0, 0))
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‎tests/baselines/reference/controlFlowInstanceOfGuardPrimitives.types

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=== tests/cases/conformance/controlFlow/controlFlowInstanceOfGuardPrimitives.ts ===
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function distinguish(thing: string | number | Date) {
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>distinguish : (thing: string | number | Date) => void
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>thing : string | number | Date
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if (thing instanceof Object) {
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>thing instanceof Object : boolean
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>thing : string | number | Date
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>Object : ObjectConstructor
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console.log("Aha!! It's a Date in " + thing.getFullYear());
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>console.log("Aha!! It's a Date in " + thing.getFullYear()) : void
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>console.log : (message?: any, ...optionalParams: any[]) => void
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>console : Console
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>log : (message?: any, ...optionalParams: any[]) => void
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>"Aha!! It's a Date in " + thing.getFullYear() : string
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>"Aha!! It's a Date in " : "Aha!! It's a Date in "
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>thing.getFullYear() : number
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>thing.getFullYear : () => number
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>thing : Date
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>getFullYear : () => number
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} else if (typeof thing === 'string') {
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>typeof thing === 'string' : boolean
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>typeof thing : "string" | "number" | "boolean" | "symbol" | "undefined" | "object" | "function"
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>thing : string | number
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>'string' : "string"
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console.log("Aha!! It's a string of length " + thing.length);
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>console.log("Aha!! It's a string of length " + thing.length) : void
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>console.log : (message?: any, ...optionalParams: any[]) => void
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>console : Console
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>log : (message?: any, ...optionalParams: any[]) => void
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>"Aha!! It's a string of length " + thing.length : string
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>"Aha!! It's a string of length " : "Aha!! It's a string of length "
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>thing.length : number
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>thing : string
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>length : number
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} else {
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console.log("Aha!! It's the number " + thing.toPrecision(3));
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>console.log("Aha!! It's the number " + thing.toPrecision(3)) : void
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>console.log : (message?: any, ...optionalParams: any[]) => void
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>console : Console
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>log : (message?: any, ...optionalParams: any[]) => void
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>"Aha!! It's the number " + thing.toPrecision(3) : string
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>"Aha!! It's the number " : "Aha!! It's the number "
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>thing.toPrecision(3) : string
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>thing.toPrecision : (precision?: number) => string
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>thing : number
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>toPrecision : (precision?: number) => string
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>3 : 3
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}
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}
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distinguish(new Date());
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>distinguish(new Date()) : void
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>distinguish : (thing: string | number | Date) => void
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>new Date() : Date
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>Date : DateConstructor
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distinguish("beef");
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>distinguish("beef") : void
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>distinguish : (thing: string | number | Date) => void
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>"beef" : "beef"
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distinguish(3.14159265);
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>distinguish(3.14159265) : void
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>distinguish : (thing: string | number | Date) => void
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>3.14159265 : 3.14159265
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‎tests/cases/conformance/controlFlow/controlFlowInstanceOfGuardPrimitives.ts

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function distinguish(thing: string | number | Date) {
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if (thing instanceof Object) {
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console.log("Aha!! It's a Date in " + thing.getFullYear());
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} else if (typeof thing === 'string') {
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console.log("Aha!! It's a string of length " + thing.length);
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} else {
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console.log("Aha!! It's the number " + thing.toPrecision(3));
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}
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}
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distinguish(new Date());
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distinguish("beef");
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distinguish(3.14159265);

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