New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Overly strict type narrowing in tuple #27557

Closed

westonpace opened this issue Oct 4, 2018 · 1 comment

Labels

Duplicate

westonpace commented Oct 4, 2018

TypeScript Version: 3.2.0-dev.201xxxxx

Search Terms:
type narrowing tuple
type inference tuple

Code

const x: [number, number] = [0, 0];
if (x[0] === 0) {
    x[0] = -1;
}

Expected behavior:
The code should compile. The above code does compile with typescript@3.0.3.

Actual behavior:

error TS2322: Type '-1' is not assignable to type '0'.

Playground Link: http://www.typescriptlang.org/play/

Related Issues:

The text was updated successfully, but these errors were encountered:

ghost added the Bug label

Member

ahejlsberg commented Oct 5, 2018

Duplicate of #27412.

ahejlsberg added Duplicate and removed Bug labels

sandersn added a commit that referenced this issue


          Elt access assignment uses declared, not narrowed type

f5190d1

I forgot to do this in #26424.

Fixes #27557
Fixes #27412

sandersn mentioned this issue

Element access assignment uses declared type, not narrowed type #27574

Merged

sandersn closed this as completed in #27574

sandersn added a commit that referenced this issue


          Elt access assignment uses declared, not narrowed type (#27574)

c080324

I forgot to do this in #26424.

Fixes #27557
Fixes #27412

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment