--- /dev/null
+"use strict";
+
+const isAutoprefixable = require("../../utils/isAutoprefixable");
+const isStandardSyntaxAtRule = require("../../utils/isStandardSyntaxAtRule");
+const report = require("../../utils/report");
+const ruleMessages = require("../../utils/ruleMessages");
+const validateOptions = require("../../utils/validateOptions");
+
+const ruleName = "at-rule-no-vendor-prefix";
+
+const messages = ruleMessages(ruleName, {
+ rejected: p => `Unexpected vendor-prefixed at-rule "@${p}"`
+});
+
+const rule = function(actual) {
+ return function(root, result) {
+ const validOptions = validateOptions(result, ruleName, { actual });
+ if (!validOptions) {
+ return;
+ }
+
+ root.walkAtRules(atRule => {
+ if (!isStandardSyntaxAtRule(atRule)) {
+ return;
+ }
+
+ const name = atRule.name;
+
+ if (name[0] !== "-") {
+ return;
+ }
+
+ if (!isAutoprefixable.atRuleName(name)) {
+ return;
+ }
+
+ report({
+ message: messages.rejected(name),
+ node: atRule,
+ result,
+ ruleName
+ });
+ });
+ };
+};
+
+rule.ruleName = ruleName;
+rule.messages = messages;
+module.exports = rule;