c++ - Is this implementation of std::decay a correct one -

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is implementation of std::decay correct one?

template<class t> t decaytype(t);  template<class t> struct decay {     using type = decltype(decaytype(declval<t>())); };

i ask because came across uses template branching manipulate type while seems acting definition.

forming function call requires passing value, requires copy/move constructor. implementation not general enough.

it gist of std::decay does, though.


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