Microsoft/TypeScript

`.call` selects the wrong overload for `String.prototype.replace`

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#29,789 opened on Feb 7, 2019

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 (3 comments) (2 reactions) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
BugDomain: lib.d.tsHelp Wanted

Description

TypeScript Version: v3.3.1 and v3.4.0-dev.20190206

Search Terms: call replace overload

Code

String.prototype.replace.call(
    'one string',
    /a/g,
    'two string', // this line errors
);

It's worth noting that this is in a JS file, not a TS file, but I'm using allowJs and checkJs.

Expected behavior: No error.

Actual behavior: errors with error TS2345: Argument of type '"two string"' is not assignable to parameter of type '(substring: string, ...args: any[]) => string'

Playground Link: http://www.typescriptlang.org/play/#src=String.prototype.replace.call(%0D%0A%20%20%20%20'one%20string'%2C%0D%0A%20%20%20%20%2Fa%2Fg%2C%0D%0A%20%20%20%20'two%20string'%2C%0D%0A)%3B but the error doesn't seem to show up there.

Related Issues: no

Contributor guide

Tech stack
typescript
Domain
tooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScript overload resolutionJavaScript String.replaceTypeScript compiler internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the overload resolution for String.prototype.replace.call in the context of JavaScript files with checkJs enabled. The issue is that when calling .call with arguments, TypeScript selects the wrong overload (the one expecting a function instead of a string). Check the checker.ts file for the overload resolution logic, particularly for .call on functions. Also, verify if the issue is reproducible in newer versions of TypeScript.