Provide clear throw on {{#each}}

Fixes #773

lib/handlebars/base.js

@@ -97,10 +97,8 @@ function registerDefaultHelpers(instance) {
   });
 
   instance.registerHelper('each', function(context, options) {
-    // Allow for {{#each}}
     if (!options) {
-      options = context;
-      context = this;
+      throw new Exception('Must pass iterator to #each');
     }
 
     var fn = options.fn, inverse = options.inverse;

spec/builtins.js

@@ -1,4 +1,4 @@
-/*global CompilerContext, shouldCompileTo, compileWithPartials, handlebarsEnv */
+/*global CompilerContext, shouldCompileTo, shouldThrow, compileWithPartials, handlebarsEnv */
 describe('builtin helpers', function() {
   describe('#if', function() {
     it("if", function() {
@@ -182,9 +182,10 @@ describe('builtin helpers', function() {
     });
 
     it("each on implicit context", function() {
-      var string   = "{{#each}}{{text}}! {{/each}}cruel world!";
-      var hash     = [{text: "goodbye"}, {text: "Goodbye"}, {text: "GOODBYE"}];
-      shouldCompileTo(string, [hash], "goodbye! Goodbye! GOODBYE! cruel world!");
+      shouldThrow(function() {
+        var template = CompilerContext.compile("{{#each}}{{text}}! {{/each}}cruel world!");
+        template({});
+      }, handlebarsEnv.Exception, 'Must pass iterator to #each');
     });
   });