ImportC: Should this compile?

[bachmeier]

On Sunday, 19 December 2021 at 02:57:35 UTC, Mike Parker wrote:
> On Saturday, 18 December 2021 at 22:31:38 UTC, bachmeier wrote:
>> I've been trying to get the stb header library to compile. 
>> There's a single remaining failure:
>>
>> ```
>> typedef struct
>> {
>>    unsigned char c[4];
>> } stb_easy_font_color;
>> stb_easy_font_color c = { 255,255,255,255 }; // use structure 
>> copying to avoid needing depending on memcpy()
>> ```
>>
>> LDC returns
>>
>> ```
>> stb_easy_font.c(892): Error: 3 extra initializer(s) for 
>> `struct __tag21`
>> ```
>>
>> Is this a bug in ImportC or is it correct that it doesn't 
>> compile? What's the best way to fix it while keeping the same 
>> behavior and performance?
>
> Unless C11 has changed the rules about nested initializers, 
> that should compile. You might try explicit nesting:
>
> ```d
> stb_easy_font_color c = { {255,255,255,255} };
> ```
>
> And please file an issue if there isn't one already.
>
>
>> (I don't know what struct __tag21 is. It's not anywhere in the 
>> source. Assuming that's just a bad error message.)
>
> A "tag" is the name of a struct or union, which follows the 
> keyword:
>
> ```c
> struct Foo {};
> ```
>
> Here, `Foo` is the tag. Instances of the struct must be 
> declared as `struct Foo`. Think of it like this: `int` is 
> required in declarations of instances of type `int`, so 
> `struct` is required in declarations of type `struct`; the 
> "tag" specifies which struct type, hence `struct Foo x`.
>
> `typedef` introduces an alias:
>
> ```c
> typedef struct Bar {} Bar;
> ```
>
> So `Bar` is now an alias for `struct Bar`, and instances can be 
> declared as `Bar x`.
>
> Your example is like this:
>
> ```c
> typedef struct {} stb_easy_font_color;
> ```
>
> No tag is specified, so the compiler must generate one. In your 
> case, it's `__tag21` and `stb_easy_font_color` is an alias for 
> `struct __tag21`.
>
> And yes, using the generated tag in the error message is not at 
> all helpful without the alias. Please file an issue on this, 
> too.

Thanks - issues created:

[Issue 1](https://issues.dlang.org/show_bug.cgi?id=22610)
[Issue 2](https://issues.dlang.org/show_bug.cgi?id=22611)