Bug 23189 – importC: __builtin_offsetof without struct/union/enum should emit proper error message

The following code is valid in C, but doesn't compile in ImportC ``` union nk_page_data *pd = (union nk_page_data*)((void*)((char*)(1 ? (tbl): &((union nk_page_data*)0)->tbl) - (__builtin_offsetof(nk_page_data,tbl)))); ```

Here is a usable code to test: ``` struct nk_table { void* test; }; union nk_page_data { struct nk_table tbl; }; void test(void) { struct nk_table *tbl; union nk_page_data *pd = (union nk_page_data*)((void*)((char*)(1 ? (tbl): &((union nk_page_data*)0)->tbl) - (__builtin_offsetof(union nk_page_data,tbl)))); } ```

Oops the code above is the actual fix.. Here the actual problematic code: ``` struct nk_table { void* test; }; union nk_page_data { struct nk_table tbl; }; void test(void) { struct nk_table *tbl; union nk_page_data *pd = (union nk_page_data*)((void*)((char*)(1 ? (tbl): &((union nk_page_data*)0)->tbl) - (__builtin_offsetof(k_page_data,tbl)))); } ``` __builtin_offsetof requires 'union', without it, i get the error: ``` bug.c(15): Error: expression expected, not `)` bug.c(15): Error: found `0` when expecting `)` ```

Ok apparently, it is required to have them, but that was the output of the clang preprocessor.. hmm Anyways.. i think a proper error message would be more useful that what is currently emitted!

(In reply to ryuukk_ from comment #0) > The following code is valid in C, but doesn't compile in ImportC It doesn't compile with gcc either.

I'm not real sure what the problem is you're reporting. It's not clear what you expect to compile?

Here is a reduced code: ``` #define NK_OFFSETOF(st,m) (__builtin_offsetof(st,m)) #define NK_ALIGNOF(t) NK_OFFSETOF(struct {char c; t _h;}, _h) struct nk_command{}; void test() { const int align = NK_ALIGNOF(struct nk_command); } ``` // using cpp -P -E ``` void test() { const int align = (__builtin_offsetof(struct {char c; struct nk_command _h;},_h)); } ``` This code compile with GCC, but not with D importc: bar.c(4): Error: expression expected, not `struct` bar.c(4): Error: found `{` when expecting `)` bar.c(4): Error: found `char` when expecting `)` bar.c(4): Error: missing comma or semicolon after declaration of `extern ()`, found `c` instead bar.c(4): Error: identifier or `(` expected bar.c(5): Error: identifier or `(` expected

It appears to compile correctly now.