Crash on trying to apply invalid type predicate

[zhuravlikjb]

class A {
    constructor(...args) {

    }

    q: string;
}

class V extends A {
    m: number;
}


class S extends A {
    m: number;
}

var m = new A(...[1, 3]);

declare function isV(): m is V; 

if (isV()) { 
    m.m; 
}

C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript>node built\local\tsc.js
 hello.ts
C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript\built\local\tsc.js:1720
2
            for (var parent_5 = node.parent; parent_5; parent_5 = parent_5.par
                                    ^
TypeError: Cannot read property 'parent' of undefined
    at resolveLocation (C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript
\built\local\tsc.js:17202:37)
    at getSymbolAtLocation (C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeSc
ript\built\local\tsc.js:17211:13)
    at narrowTypeByTypePredicate (C:\Users\Anton.Lobov\Desktop\ts-latest-github\
TypeScript\built\local\tsc.js:17409:21)
    at narrowType (C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript\buil
t\local\tsc.js:17425:32)
    at getNarrowedTypeOfSymbol (C:\Users\Anton.Lobov\Desktop\ts-latest-github\Ty
peScript\built\local\tsc.js:17248:52)
    at checkIdentifier (C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript
\built\local\tsc.js:17469:20)
    at checkExpressionWorker (C:\Users\Anton.Lobov\Desktop\ts-latest-github\Type
Script\built\local\tsc.js:19888:28)
    at checkExpression (C:\Users\Anton.Lobov\Desktop\ts-latest-github\TypeScript
\built\local\tsc.js:19863:42)
    at checkPropertyAccessExpressionOrQualifiedName (C:\Users\Anton.Lobov\Deskto
p\ts-latest-github\TypeScript\built\local\tsc.js:18247:24)
    at checkPropertyAccessExpression (C:\Users\Anton.Lobov\Desktop\ts-latest-git
hub\TypeScript\built\local\tsc.js:18241:20)

[zhuravlikjb]

By the way, should type predicates operating on something other than predicate-function arguments work, or should it be a compiler error? Thanks.

[JsonFreeman]

It should be a compiler error

[mhegazy]

thanks @tinganho