Error: Failed to add @ts-expect-error within template expression.

[airbnb]

Error: Failed to add @ts-expect-error within template expression.

[mvanbutselaar]

Been getting this Error: Failed to add @ts-expect-error within template expression. as well. In my case this only happens when having the addConversionsPlugin enabled, but it might happen due to other text/line/formatting changes as well. In my case it actually tries to add a @ts-expect-error about setTimeout not being defined (had the the DOM lib disabled), but the offending line did nothing with setTimeout. As if the diagnostic was not referring to the correct position. Which is possible, as some empty lines are stripped and some formatting changed occur due to the transformations done by addConversionsPlugin.

I am not using the ts-migrate command directly (or ts-migrate-server for that matter), but my code is heavily based on that code, I found that in this ts-migrate-server/src/migrate/index.ts#L85 there was an issue. The sourceFile changes, and the current sourceFile and diagnostics might be incorrect. Fixed this by updating the sourceFile const in the plugins/sourceFiles loops to update with the return value from project.updateSourceFile. This might have already been an issue before, but this commit of ts-migrate has only made it worse.

Hope this helps you, or helps in creating a fix.

[Rudeg]

haven't seen this before. Could you please share source code or an example, where it failed?

[jamestowers]

I get this when converting styled components:

export const ButtonStyled = styled.button `
  // It tries to add @ts-expect-error here
  ${props => props.isSmall &&
    css `
      ${SmallButtonStyles}
    `}
`;