With a simple code of
{{#each array}}
{{@index}}: {{this}}
{{/each}}
a flood of errors appears. Same happens with {{@key}}
for objects. Why does it happen?
Looking at the source (at https://github.com/meteor/meteor/blob/master/packages/handlebars/parse.js): It doesn't look like the {{@ ..}}
set of expressions are supported with the Handlebars version packaged with Meteor.