Remove restriction of displaying semantic diagnostic in TypeScript files in custom schemes

[zardoy]

Hi! I'm building an extension, which uses its own scheme instead of untitled to control process of saving. And as I can see, semanitc diagnostics are being filtered out in my editors, however they're working fine just like as any other inferred project such as in Unittled files.

vscode/extensions/typescript-language-features/src/utils/fileSchemes.ts

Lines 17 to 22 in 1872bc1

	export const semanticSupportedSchemes = [
	file,
	untitled,
	walkThroughSnippet,
	vscodeNotebookCell,
	];

I'm just curious why even this restriction exists?

My feature request here is to let other extensions contributing system providers use full TS experience by display semantic diagnostics in all schemes.

[mjbvz]

Duplicate of microsoft/TypeScript#47600

This limitations exists because the TypeScript server can't read files that use custom schemes. This means that imports can't be resolved, which causes false errors

[zardoy]

But in my case my extension doesn't mean to support file imports. It's something like playground, I just need diagnostics for current file only, for example:

const a = 5
a = 'test'
// would print nothing, too annoying

@mjbvz this limitation is too strict! I would like to see a way to workaround by configuring builtin TypeScript extension with its API to add support for custom schemes. like api.addScheme()