--- /dev/null
+"use strict";
+
+const postcss = require("postcss");
+const report = require("../../utils/report");
+const ruleMessages = require("../../utils/ruleMessages");
+const shorthandData = require("../../reference/shorthandData");
+const validateOptions = require("../../utils/validateOptions");
+
+const ruleName = "declaration-block-no-shorthand-property-overrides";
+
+const messages = ruleMessages(ruleName, {
+ rejected: (shorthand, original) =>
+ `Unexpected shorthand "${shorthand}" after "${original}"`
+});
+
+const rule = function(actual) {
+ return (root, result) => {
+ const validOptions = validateOptions(result, ruleName, { actual });
+ if (!validOptions) {
+ return;
+ }
+
+ root.walkRules(check);
+ root.walkAtRules(check);
+
+ function check(statement) {
+ const declarations = {};
+ // Shallow iteration so nesting doesn't produce
+ // false positives
+ statement.each(node => {
+ if (node.type !== "decl") {
+ return;
+ }
+
+ const prop = node.prop;
+ const unprefixedProp = postcss.vendor.unprefixed(prop);
+ const prefix = postcss.vendor.prefix(prop).toLowerCase();
+
+ const overrideables = shorthandData[unprefixedProp.toLowerCase()];
+ if (!overrideables) {
+ declarations[prop.toLowerCase()] = prop;
+ return;
+ }
+ overrideables.forEach(longhandProp => {
+ if (!declarations.hasOwnProperty(prefix + longhandProp)) {
+ return;
+ }
+ report({
+ ruleName,
+ result,
+ node,
+ message: messages.rejected(
+ prop,
+ declarations[prefix + longhandProp]
+ )
+ });
+ });
+ });
+ }
+ };
+};
+
+rule.ruleName = ruleName;
+rule.messages = messages;
+module.exports = rule;