Skip type checking project reference redirect(declaration file from project reference) to improve perf

[sheetalkamat]

Search Terms

Suggestion

We could probably set internal option and skip type checking project reference redirects (included .d.ts files from project reference output)
This could speed up tsc --b mode by skipping type checking generated files, (eg. skip compiler.d.ts when building tsc project and so on...) Since in build mode referencing projects are not built if there are any errors in the referenced project this should report all errors.

Use Cases

Examples

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript / JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. new expression-level syntax)

[DanielRosenwasser]

Wouldn't --skipLibCheck already give you this?

[weswigham]

It would, yea.

[ajafff]

Is this proposal only for TypeScript's internal use to compile itself or is it intended for all users of project references?

If the consuming project has different compiler options than the referenced project, there might be type errors in the declaration files. Therefore type checking declaration files of referenced projects should not be turned off by default.

[amcasey]

Did we end up doing this? We don't actually type check our own output if --skipLibCheck isn't set, do we?