[Issue 23184] New: importC: array division with sizeof is problematic

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23184

          Issue ID: 23184
           Summary: importC: array division with sizeof is problematic
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: blocker
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: ryuukk.dev at gmail.com

I have no clue how it is called, pardon my ignorance, but i came across that
snippet of code that is causing an issue:

```
static const char nk_utfmask[4 +1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};

void test()
{
    int a = (int)(sizeof(nk_utfmask)/sizeof(nk_utfmask)[0]);
}
```

it is the result of that macro: [1]

called here: [2]


using clang preprocessor the actual code:

```
static nk_rune
nk_utf_decode_byte(char c, int *i)
{
    ((i) ? (void)0 : __assert_func ("./nuklear_all.h", 7976, __func__, "i"));
    if (!i) return 0;
    for(*i = 0; *i < (int)(sizeof(nk_utfmask)/sizeof(nk_utfmask)[0]); ++(*i)) {
        if (((nk_byte)c & nk_utfmask[*i]) == nk_utfbyte[*i])
            return (nk_byte)(c & ~nk_utfmask[*i]);
    }
    return 0;
}
```



[1]
https://github.com/Immediate-Mode-UI/Nuklear/blob/11d8acfd4fbb9d0966161fa01d58be15be1974e3/src/nuklear.h#L5455
[2]
https://github.com/Immediate-Mode-UI/Nuklear/blob/11d8acfd4fbb9d0966161fa01d58be15be1974e3/src/nuklear_utf8.c#L30

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