support the unrestricted tag (Closure Compiler only) (#605)

lib/jsdoc/tag/dictionary/definitions.js

@@ -983,7 +983,11 @@ exports.closureTags = {
     type: cloneTagDef(baseTags.type, {
         mustNotHaveDescription: false
     }),
-    typedef: cloneTagDef(baseTags.typedef)
+    typedef: cloneTagDef(baseTags.typedef),
+    // Closure Compiler only
+    unrestricted: {
+        onTagged: ignore
+    }
 };
 
 function addTagDefinitions(dictionary, tagDefs) {

test/fixtures/unrestrictedtag.js

@@ -0,0 +1,7 @@
+/**
+ * My class.
+ *
+ * @constructor
+ * @unrestricted
+ */
+function Foo() {}

test/specs/tags/unrestrictedtag.js

@@ -0,0 +1,42 @@
+'use strict';
+
+describe('@unrestricted tag', function() {
+    var env = require('jsdoc/env');
+    var logger = require('jsdoc/util/logger');
+
+    var allowUnknownTags = Boolean(env.conf.tags.allowUnknownTags);
+
+    beforeEach(function() {
+        env.conf.tags.allowUnknownTags = false;
+        spyOn(logger, 'error');
+    });
+
+    afterEach(function() {
+        jasmine.restoreTagDictionary();
+        env.conf.tags.allowUnknownTags = allowUnknownTags;
+    });
+
+    describe('JSDoc tags', function() {
+        beforeEach(function() {
+            jasmine.replaceTagDictionary('jsdoc');
+        });
+
+        it('should not recognize the @unrestricted tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/unrestrictedtag.js');
+
+            expect(logger.error).toHaveBeenCalled();
+        });
+    });
+
+    describe('Closure Compiler tags', function() {
+        beforeEach(function() {
+            jasmine.replaceTagDictionary('closure');
+        });
+
+        it('should recognize the @unrestricted tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/unrestrictedtag.js');
+
+            expect(logger.error).not.toHaveBeenCalled();
+        });
+    });
+});