microsoft / microsoft/TypeScript

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

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Bug Domain: lib.d.ts Help Wanted
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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

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the provided JavaScript repro using String.prototype.replace.call, with allowJs and checkJs enabled, and trace how the replace overload is selected. Confirm the behavior against the reported TypeScript versions and verify that the call accepts the replacement string without TS2345 while preserving the existing overload behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
javascript, typescript
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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