Avoid errors when no predicate is present.

Author: Robert Jackson

fixtures/deprecate-expansion/expectation.js

@@ -1 +1,2 @@
-(true && !(true) && console.warn('This is deprecated'));
+(true && !(true) && console.warn('This is deprecated'));
+(true && !(false) && console.warn('Message without predicate'));

fixtures/deprecate-expansion/sample.js

@@ -1,4 +1,5 @@
 import { DEBUG } from '@ember/env-flags';
 import { deprecate } from '@ember/debug-tools';
 
-deprecate('This is deprecated', true);
+deprecate('This is deprecated', true);
+deprecate('Message without predicate');

fixtures/ember-cli-babel-config/expectation.js

@@ -6,6 +6,7 @@ if (true) {
 
 (true && Ember.warn('This is a warning'));
 (true && !(foo) && Ember.assert('Hahahaha', false));
+(true && !(false) && Ember.assert('without predicate', false));
 (true && !(true) && Ember.deprecate('This thing is donzo', false, {
   id: 'donzo',
   until: '4.0.0',

fixtures/ember-cli-babel-config/sample.js

@@ -8,6 +8,7 @@ if (DEBUG) {
 warn('This is a warning');
 
 assert('Hahahaha', foo);
+assert('without predicate');
 
 deprecate('This thing is donzo', true, {
   id: 'donzo',

src/lib/utils/builder.js

@@ -122,7 +122,7 @@ export default class Builder {
     let prefixedIdentifiers = [];
 
     if (options.predicate) {
-      let predicate = options.predicate(expression, args);
+      let predicate = options.predicate(expression, args) || t.identifier('false');
       let negatedPredicate = t.unaryExpression('!', t.parenthesizedExpression(predicate));
       prefixedIdentifiers.push(negatedPredicate);
     }