Returning anything from build macro interferes with field type completion.

Minimal example:

```haxe
#if !macro
@:build(Main.build())
#end
class Main {
#if !macro
var name:|
static function main() {}
#else
static function build() {
var ret = haxe.macro.Context.getBuildFields();
return ret;// return null works
}
#end
}
```

The compiler seems a little confused:


Without returning any changes (i.e. `return null` as suggested in the comment), it works:


Also, if you type at least one letter and force completion (or type two letters), you get type completion: