Skip to content

Type argument inference does not take call's contextual type into account #10245

Closed
@zakjan

Description

@zakjan

TypeScript Version: 2.0.0

Code

function map(array: number[]): [number, number][] {
    return array.map((x: number) => [x, x * x]);
}

Expected behavior:
no error

Actual behavior:

error TS2322: Type 'number[][]' is not assignable to type '[number, number][]'.
  Type 'number[]' is not assignable to type '[number, number]'.
    Property '0' is missing in type 'number[]'.

Metadata

Metadata

Assignees

No one assigned

    Labels

    Needs ProposalThis issue needs a plan that clarifies the finer details of how it could be implemented.SuggestionAn idea for TypeScript

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions