Possible incorrect variable reference.

[coreyfarrell]

Sorry if this is not a real bug. Current code at https://github.com/Polymer/polymer/blame/master/lib/utils/mixin.html#L54 checks for mixin.__id, then sets mixin.__dedupeId. Seems like the same property should be used all the time. This bug report is based purely on my belief that "this looks wrong", I have not seen it cause trouble in real life.

This code was originally added by @sorvell:

• ef69503#diff-37d29f6fc5721ddc3d2248a84cfcc681R117

[dfreedm]

Yeah, that seems suspicious. Thanks!

[dfreedm]

The __dedupeId is set on mixin function creation, so the check doesn't matter.
The caching functionality also makes sure that any funky nesting of dedupingMixin will end in the same output class.
Since the check doesn't work anyway, I'll remove it.