Can using be used to type alias an array?

问题

I'm not sure I've worded this properly since this is a bit of an odd situation. Basically I've found some code like this:

template<class T>
struct X { typedef T Type; };

template<class T>
struct X<const T[]> { typedef T Type[]; }

And I was in the process of changing the typedefs to use the C++11 using type-alias syntax when I realised this doesn't seem to work for the second example.

i.e. it isn't possible to do:

template<class T>
struct X<const T[]> { using Type[] = T; }

Why is this? Is this an 'oversight' by the standards comittee?

回答1:

The right syntax is:

using Type = T[];

which defines that Type has the type "array of unknown bound of T".

来源：https://stackoverflow.com/questions/43013243/can-using-be-used-to-type-alias-an-array