extensions/typescript-language-features/src/utils/relativePathResolver.ts/RelativeWorkspacePathResolver/asAbsoluteWorkspacePath
class RelativeWorkspacePathResolver:	public static asAbsoluteWorkspacePath(relativePath: string): string | undefined {
		for (const root of vscode.workspace.workspaceFolders || []) {
			const rootPrefixes = [`./${root.name}/`, `${root.name}/`, `.\\${root.name}\\`, `${root.name}\\`];
			for (const rootPrefix of rootPrefixes) {
				if (relativePath.startsWith(rootPrefix)) {
					return path.join(root.uri.fsPath, relativePath.replace(rootPrefix, ''));
				}
			}
		}

		return undefined;
	}