[clang] [C99] Claim conformance for _Complex support (PR #88161)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> You're missing checks for type domain rules, so things like:
> 
>     * converting between `float _Complex` and `double _Complex`
> 
>     * common type of `float _Complex` and `double`
> 
>     * result of `int` and `float _Complex`
> 
>     * complex types not allowed in increment/decrement operators
> 
>     * complex types permitted in unary +, -

Thanks for the suggestions, these are now being tested.

> Not sure how to test this, but _Complex float not promoting to _Complex double like float does to double is also worth slotting under complex conformance. Also 6.7.8p10 (static-storage duration arithmetic types (which include complex types) are initialized to 0).

I'll add tests for these as well.


https://github.com/llvm/llvm-project/pull/88161