我有一些代码对我来说似乎没有歧义，但gcc4.7令人窒息:#include#includeusingnamespacestd;//Containerformixinstemplateclass...Mixins>structMix:Mixins>...{typedeftuple>...>types;};//OuterlayerextractsthetypetuplefromtheargumenttemplatestructInnerCombiner{typedeftypenameInnerCombiner::typetype;};//Typedeftypetobeanewmixofth