emitDts should print diagnostic messages

[dangreen]

Describe the bug

When there is a type error in a svelte component, emitDts just silently doesn't emit .d.ts file

Reproduction

Any svelte component with type error

Expected behaviour

language-tools/packages/svelte2tsx/src/emitDts.ts

Line 16 in 6ef2442

program.emit();

here need to handle the result of emit, and print diagnostic messages if any exists

System Info

• OS: any
• IDE: any

Which package is the issue about?

svelte2tsx

Additional Information, eg. Screenshots

Related issue: sveltejs/kit#3783

[dummdidumm]

emitDts is a primitive who's job is not type checking. The error messages that come from it would probably contain a lot of weird things and false positives; also the line/columns of the errors would be all wrong because they use the generated code, which is why we wrap its usage inside the svelte-language-server to augment/adjust the output.

I think the better way would be to run svelte-check before running svelte-package.