First of all, what is the correct term for T[] (not T[12] and not T*)?
Second, if T is both trivially copyable and trivially destructible, why is T[] trivially copyable but not trivially destructible? I know it is for bounded arrays (T[12]).
First of all, what is the correct term for T[]
It is an array of unknown bound (shortened to AOUB below).
Why is T[] not trivially destructible?
Standard (latest draft):
[meta.unary.prop]
Trait: is_trivially_destructible
Condition: is_destructible_v is true and ...
Trait: is_destructible
Condition: Either T is a reference type, or T is a complete object type for which ...
An AOUB is neither a reference type, nor is it a complete type. Thus it does not have the trait is_destructible and thus it has is_trivially_destructible neither.
Why is T[] trivially copyable
Standard (latest draft):
[meta.unary.prop]
Trait: is_trivially_copyable
Condition: T is a trivially copyable type ([basic.types])
[basic.types.general]
Arithmetic types ..., arrays of such types, and ... are collectively called trivially copyable types.
Note that there is no exception for arrays of unknown bound. They are trivially copyable too according to this rule.
