Created attachment 201734 [details]
Testcase demonstrating the issue.

Some forms of array usage in async methods generates wrong C code.

I'm not sure which of the following is actually legal inside async method:

int[1] a = { -1 }; // compiles ok
int b[1] = { -1 }; // cc error
int c[] = { -1 }; // cc error

but all are accepted by valac, while the later two then fail at the C compilation stage.

The issue is reproducible on vala git 16fa519730b7b0a4df65179e94b75678371fb361, but also on an ancient vala in debian repo (0.12.1).

Testcase is attached. As I said, I'm not sure what all is actually legal inside an async method, but if the code is not legal, valac should report appropriate error.