# Expect a `XMLDecl` production, without the initial `<?xml` token.
	private fun expect_xml_decl: Bool do
		if not expect_version_info then return false
		if lexer.accept_s then
			if lexer.is_char('e') then
				if not expect_encoding_decl then return false
				# At this point, we can only accept `S` or `'?>'`.
				if not lexer.accept_s then
					return lexer.expect_string("?>", "")
				end
			end
			if lexer.is_char('s') and not expect_sd_decl then return false
			return lexer.skip_s and lexer.expect_string("?>", "")
		else
			return lexer.expect_string("?>", "")
		end
	end