Transform @apply(--foo) to @apply --foo

src/all-passes.ts

@@ -15,4 +15,5 @@
 // This file imports all passes, causing them to be registered.
 
 import './html/move-style-into-template';
+import './css/at-apply-not-function';
 import './css/var-statement-prop-fallback';

src/css/at-apply-not-function.ts

@@ -0,0 +1,53 @@
+/**
+ * @license
+ * Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
+ * This code may only be used under the BSD style license found at
+ * http://polymer.github.io/LICENSE.txt
+ * The complete set of authors may be found at
+ * http://polymer.github.io/AUTHORS.txt
+ * The complete set of contributors may be found at
+ * http://polymer.github.io/CONTRIBUTORS.txt
+ * Code distributed by Google as part of the polymer project is also
+ * subject to an additional IP rights grant found at
+ * http://polymer.github.io/PATENTS.txt
+ */
+
+import {ParsedCssDocument} from 'polymer-analyzer/lib/css/css-document';
+import * as shadyCss from 'shady-css-parser';
+import * as stripIndent from 'strip-indent';
+
+import {registry} from '../registry';
+
+import {CssUpgradePass} from './css-pass';
+
+
+class FixAtApplyWithInvalidParens extends CssUpgradePass {
+  code = 'at-apply-not-function';
+  description = stripIndent(`
+      Transforms the invalid expression:
+      
+          @apply(--foo)
+      
+      Into the valid:
+      
+          @apply --foo;
+  `);
+
+  constructor() { super(); }
+
+  upgrade(document: ParsedCssDocument) {
+    document.visit([{
+      visit(node: shadyCss.Node, _path: shadyCss.Node[]) {
+        if (node.type === 'atRule' && node.name === 'apply') {
+          const badApplyMatcher = /^\s*\((.*)\)\s*$/;
+          const match = node.parameters.match(badApplyMatcher);
+          if (match) {
+            node.parameters = `${match[1]}`;
+          }
+        }
+      }
+    }]);
+  }
+}
+
+registry.register(new FixAtApplyWithInvalidParens());

src/test/fixtures/at-apply-not-function/after/index.css

@@ -0,0 +1,3 @@
+body {
+  @apply --erratic-jumping;
+}

src/test/fixtures/at-apply-not-function/before/index.css

@@ -0,0 +1,3 @@
+body {
+  @apply(--erratic-jumping)
+}