partial initialization of fixed size ("static") arrays

[kdevel]

On Saturday, 14 August 2021 at 23:09:14 UTC, Paul Backus wrote:
> On Saturday, 14 August 2021 at 14:04:47 UTC, kdevel wrote:
>> ~~~
>>    char [7] d7 = "x"; // okay
>>
>>    string s = "x";
>>    char [7] c7 = s; // throws RangeError
>> ~~~
>>
>> What justifies that the compiler behaves differently on two 
>> terms ('s', '"x"') which are of equal size, type, length and 
>> value?
>
> Literals in D can have different types in different contexts. 
> For example:
>
> ```d
> byte b = 16; // 16 is treated as a byte literal
> int n = 16; // 16 is treated as an int literal
> b = n; // Error: cannot convert int to byte
> ```

The wording of the error message

~~~d
void main () // bi.d
{
    byte b = 257;
}

$ dmd bi.d
bi.d(3): Error: cannot implicitly convert expression `257` of 
type `int` to `byte`
~~~

does not seem to support your interpretation. The term `257` does 
not encode a ‘polymorphic’ entity but the int value 257 which is 
used to initialize a variable. If necessary, the value is 
converted. The literal is not “typeless” as in Go [1] either.

> Similarly, the string literal `"x"` can be treated either as a 
> `string` (a dynamic array of `immutable(char)`) or as a static 
> array of `char`, depending on the type of variable it's 
> assigned to.

[1] https://blog.golang.org/constants