Variable names and library names can conflict

[vsmenon]

I'm hitting an error in generated code where a local variable name is shadowing a global library name:

    instantiate(key) {
      let binding = this.injector[_getBinding](key);
      if (lang.isBlank(binding))
        return exports[_notFound];
      this.injector[_markAsConstructing](key);
      let deps = this.injector[_resolveDependencies](key, dart.as(binding, binding.Binding), true);

In particular, in:

dart.as(binding, binding.Binding)

The first binding should be the local var, and the second should be the binding library.

[jmesserly]

Yeah, one of the things it would be nice to address as part of a ES6 modules story.

What's happening is our "module pattern" is introducing names into the user's scope that were not supposed to be there (in the original Dart code)

Renaming the local is tempting, however, I think that's probably the wrong approach, because the local should have the debugger friendly name. It's the qualified module name that is the compiler-generated variable. Or even better: avoid qualifying when possible**, such as in this case. Instead import the names that are used.

(** qualification is required for lazy statics though)

[jmesserly]

https://codereview.chromium.org/1122133003