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=== tests/cases/compiler/literalFreshnessPropagationOnNarrowing.ts ===
function f1() {
>f1 : () => void
let b = true;
>b : boolean
>true : true
let obj = { b };
>obj : { b: boolean; }
>{ b } : { b: boolean; }
>b : boolean
// Desired: OK
// 3.0: OK
// 3.1 as-is: OK
// 3.1 minus widening propagation: error
obj.b = false;
>obj.b = false : false
>obj.b : boolean
>obj : { b: boolean; }
>b : boolean
>false : false
}
function f2() {
>f2 : () => void
type Element = (string | false);
>Element : string | false
>false : false
type ElementOrArray = Element | Element[];
>ElementOrArray : (string | false) | (string | false)[]
let el: Element = null as any;
>el : string | false
>null as any : any
>null : null
let arr: Element[] = null as any;
>arr : (string | false)[]
>null as any : any
>null : null
let elOrA: ElementOrArray = null as any;
>elOrA : (string | false) | (string | false)[]
>null as any : any
>null : null
// Desired/actual: All OK
let a1: ElementOrArray = el;
>a1 : (string | false) | (string | false)[]
>el : string | false
let a2: ElementOrArray = arr;
>a2 : (string | false) | (string | false)[]
>arr : (string | false)[]
let a3: ElementOrArray = [el];
>a3 : (string | false) | (string | false)[]
>[el] : (string | false)[]
>el : string | false
let a4: ElementOrArray = Array.isArray(elOrA) ? elOrA : [elOrA];
>a4 : (string | false) | (string | false)[]
>Array.isArray(elOrA) ? elOrA : [elOrA] : (string | false)[]
>Array.isArray(elOrA) : boolean
>Array.isArray : (arg: any) => arg is any[]
>Array : ArrayConstructor
>isArray : (arg: any) => arg is any[]
>elOrA : (string | false) | (string | false)[]
>elOrA : (string | false)[]
>[elOrA] : (string | false)[]
>elOrA : string | false
// Desired: OK
// 3.0: Error
// 3.1: OK
let a5: ElementOrArray = [...Array.isArray(elOrA) ? elOrA : [elOrA]];
>a5 : (string | false) | (string | false)[]
>[...Array.isArray(elOrA) ? elOrA : [elOrA]] : (string | false)[]
>...Array.isArray(elOrA) ? elOrA : [elOrA] : string | false
>Array.isArray(elOrA) ? elOrA : [elOrA] : (string | false)[]
>Array.isArray(elOrA) : boolean
>Array.isArray : (arg: any) => arg is any[]
>Array : ArrayConstructor
>isArray : (arg: any) => arg is any[]
>elOrA : (string | false) | (string | false)[]
>elOrA : (string | false)[]
>[elOrA] : (string | false)[]
>elOrA : string | false
}
function f3() {
>f3 : () => void
type XY = 'x' | 'y';
>XY : "x" | "y"
const x: XY = 'x';
>x : "x" | "y"
>'x' : "x"
let x2 = x;
>x2 : "x"
>x : "x"
// Desired: OK (up for debate?)
// 3.0: Error
// 3.1 as-is: OK
x2 = 'y';
>x2 = 'y' : "y"
>x2 : "x"
>'y' : "y"
// Desired/actual: All OK
let x3: XY = x;
>x3 : "x" | "y"
>x : "x"
x3 = 'y';
>x3 = 'y' : "y"
>x3 : "x" | "y"
>'y' : "y"
}
function f4() {
>f4 : () => void
const x: boolean = true;
>x : boolean
>true : true
let x1 = x;
>x1 : boolean
>x : true
// Desired: OK
// 3.0: OK
// 3.1: OK
// 3.1 minus widening propagation: error
x1 = false;
>x1 = false : false
>x1 : boolean
>false : false
}
function f5() {
>f5 : () => void
type XY = 'x' | 'y';
>XY : "x" | "y"
let arr: XY[] = ['x'];
>arr : ("x" | "y")[]
>['x'] : "x"[]
>'x' : "x"
arr = ['y'];
>arr = ['y'] : "y"[]
>arr : ("x" | "y")[]
>['y'] : "y"[]
>'y' : "y"
// Desired: OK
// Error in all extant branches
arr = [...['y']];
>arr = [...['y']] : string[]
>arr : ("x" | "y")[]
>[...['y']] : string[]
>...['y'] : string
>['y'] : string[]
>'y' : "y"
}
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