为什么我们只能使用初始化列表初始化数组

Question

In the following example

#include <iostream>

int a[][2] = {{1, 4}, {2, 6}};
int b[][3] = a; // error: array initializer must be an initializer list

DEMO

Why can't we initialize an array in any way instead of with an initializer-list ? I tried to find it in the N4296::8.5.4 [dcl.init.list] but it seems there is no anything suitable about it.

Answer 1

This question is sort of backwards, as is the error message. It has always been the case that you cannot initialise an array from the name of another array. Initializer lists aren't relevant to that.

[C++11: 8.5/16]: The semantics of initializers are as follows. The destination type is the type of the object or reference being initialized and the source type is the type of the initializer expression. If the initializer is not a single (possibly parenthesized) expression, the source type is not defined.

• If the initializer is a (non-parenthesized) braced-init-list , the object or reference is list-initialized (8.5.4).
• If the destination type is a reference type, see 8.5.3.
• If the destination type is an array of characters, an array of char16_t , an array of char32_t , or an array of wchar_t , and the initializer is a string literal, see 8.5.2.
• If the initializer is () , the object is value-initialized.
• Otherwise, if the destination type is an array, the program is ill-formed.
• [..]