Use before define from variables to classes.

[vsmenon]

This code (from Angular):

/// Marker for an uninitialized value.
const UNINITIALIZED = const _Uninitialized();
class _Uninitialized { const _Uninitialized(); }

is causing a runtime error on generated code as the use is before the define:

  let UNINITIALIZED = new _Uninitialized();
  class _Uninitialized extends core.Object {
    _Uninitialized() {
    }
  }

[jmesserly]

this is basically #29, consts aren't implemented

[jmesserly]

update, getting closer on this. The new design unifies all use-before-define concepts. It folds in the existing _lazyClass checks, without requiring duplication. It will also allow constants in method bodies to be hoisted out to the top-level (as an optimization, but also what a human would write in JS code).

[jmesserly]

there's essentially two mechanisms:

• ability to qualify identifiers later. In other words, exports.someName vs someName ... we don't know if we need this at first. The same mechanism should help ES6 module stuff too. (Basically, having to qualify names all the time is a drag.)
• ability to reorder all top level "module items" on-the-fly. It still defaults to source order, but things can be filled in at different places if needed.

("module items" terminology is from https://people.mozilla.org/~jorendorff/es6-draft.html#sec-modules)

[jmesserly]

https://codereview.chromium.org/1133593004/ ... finally :)