tests/cases/compiler/indexer2.ts(6,25): error TS2352: Neither type '{ [x: number]: undefined; }' nor type 'IDirectChildrenMap' is assignable to the other.
Types of property 'hasOwnProperty' are incompatible.
Type '(v: string) => boolean' is not assignable to type '(objectId: number) => boolean'.
Types of parameters 'v' and 'objectId' are incompatible.