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=== tests/cases/conformance/expressions/binaryOperators/additionOperator/additionOperatorWithUndefinedValueAndInvalidOperands.ts ===
// If one operand is the null or undefined value, it is treated as having the type of the other operand.
function foo(): void { return undefined }
>foo : () => void
>undefined : undefined
var a: boolean;
>a : boolean
var b: Object;
>b : Object
var c: void;
>c : void
var d: Number;
>d : Number
// undefined + boolean/Object
var r1 = undefined + a;
>r1 : any
>undefined + a : any
>undefined : undefined
>a : boolean
var r2 = undefined + b;
>r2 : any
>undefined + b : any
>undefined : undefined
>b : Object
var r3 = undefined + c;
>r3 : any
>undefined + c : any
>undefined : undefined
>c : void
var r4 = a + undefined;
>r4 : any
>a + undefined : any
>a : boolean
>undefined : undefined
var r5 = b + undefined;
>r5 : any
>b + undefined : any
>b : Object
>undefined : undefined
var r6 = undefined + c;
>r6 : any
>undefined + c : any
>undefined : undefined
>c : void
// other cases
var r7 = undefined + d;
>r7 : any
>undefined + d : any
>undefined : undefined
>d : Number
var r8 = undefined + true;
>r8 : any
>undefined + true : any
>undefined : undefined
>true : true
var r9 = undefined + { a: '' };
>r9 : any
>undefined + { a: '' } : any
>undefined : undefined
>{ a: '' } : { a: string; }
>a : string
>'' : ""
var r10 = undefined + foo();
>r10 : any
>undefined + foo() : any
>undefined : undefined
>foo() : void
>foo : () => void
var r11 = undefined + (() => { });
>r11 : any
>undefined + (() => { }) : any
>undefined : undefined
>(() => { }) : () => void
>() => { } : () => void
|
