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

lib/jsdoc/tag/dictionary/definitions.js

@@ -898,6 +898,10 @@ exports.closureTags = {
         onTagged: ignore
     },
     // Closure Compiler only
+    nocollapse: {
+        onTagged: ignore
+    },
+    // Closure Compiler only
     override: {
         mustNotHaveValue: true,
         onTagged: function(doclet) {

test/fixtures/nocollapsetag.js

@@ -0,0 +1,8 @@
+/**
+ * A namespace.
+ * @const
+ */
+var foo = {};
+
+/** @nocollapse */
+foo.bar = true;

test/specs/tags/nocollapsetag.js

@@ -0,0 +1,42 @@
+'use strict';
+
+describe('@nocollapse 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 @nocollapse tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/nocollapsetag.js');
+
+            expect(logger.error).toHaveBeenCalled();
+        });
+    });
+
+    describe('Closure Compiler tags', function() {
+        beforeEach(function() {
+            jasmine.replaceTagDictionary('closure');
+        });
+
+        it('should recognize the @nocollapse tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/nocollapsetag.js');
+
+            expect(logger.error).not.toHaveBeenCalled();
+        });
+    });
+});