Runtime: report good errors for top level console.log and the like

[josephjclark]

If you do this at the top of your job code:

console.log('hello')

You'll probably get a vague error like fn is not a function, and you'll be upset and you won't know what's happening.

What IS happening is that the runtime is treating the console.log call like an operation, so it's trying to call it, take the returned function, and add it to the execute pipeline.

Aside from generally printing better error messages (including source line) what can we do here?

• Well, the runtime should be able to work out that something which is not an operation was passed into its pipeline, and it should at least be able to throw a decent error message (operation 5 was not an operation - did you call an adaptor function?)
• The compiler could possibly detect console.log explicitly and raise a warning. But not only is that sketchy, Lightning doesn't include compiler logs yet (right?(