@ts-ignore is broken in 3.6 when code line is broken into 2 lines

Search Terms: @ts-ignore ts-ignore ignore multiline Code

const veryLongStructureNameWithFooInside = {
  foo: (x: number): Promise<number> => {
    return Promise.resolve(x);
  },
};
// @ts-ignore
veryLongStructureNameWithFooInside
  .foo() // Notice the line break here caused by prettier
  .then((result) => {
    console.log(result);
  })
  .catch((err) => {
    console.log(err);
  });

Expected behavior:

There should be no errors as @ts-ignore is set on the function call (works in 3.5.2)

Actual behavior:

In next version the following error occurs:

error TS2554: Expected 1 arguments, but got 0.

   .foo()
      ~~~~~

      foo: (x: number): Promise<number> => {
               ~~~~~~~~~
    An argument for 'x' was not provided.

Playground Link: playground

[sandersn]

Here’s a smaller repro:

const x = {
  foo: (x: number) => {
    return x;
  },
};
// @ts-ignore
x
.foo() // Notice the line break here caused by prettier

This is definitely a regression in 3.6, although the new behaviour seems right to me – I believe ts-ignore is defined in terms of lines, not expressions. It makes ts-ignore + prettier hard to use consistently though.

[lamontadams]

This is also affecting React tsx components broken across multiple lines, which is problematic because quite a few React components tend to have poor or unmaintained typings. Prior to 3.6 I could ts-ignore a single property assignment by putting it on one line and still have type support for the other properties exposed by a component. Now I have to ignore the entire component declaration when this happens - and it really frustrates my efforts to get the rest of my team sold on Typescript.

I’m also “stuck” on 3.5 until this gets fixed.

FYI - I wound up here after filing https://github.com/microsoft/vscode/issues/80715 against VSCode.