Why not use the compatible type __attribute__((__noreturn__)) as __NO_RETURN for IAR?

[SuperHeroAbner]

The type of attribute((noreturn)) can be put before or after function like 'void func(void) __NO_RETURN;'. If use the type of [[noreturn]] or _Noreturn, it must be like '__NO_RETURN void func(void)'
CMSIS_6 https://github.com/ARM-software/CMSIS_6/blob/main/CMSIS/Core/Include/cmsis_iccarm.h#L57
CMSIS_5 https://github.com/ARM-software/CMSIS_5/blob/develop/CMSIS/Core/Include/cmsis_iccarm.h#L130
This introduces compatibility issue. Does attribute((noreturn)) have any issue to apply on IAR compared with _Noreturn + [[noreturn]] ?

[JonatanAntoni]

The compiler header for IAR is provided and maintained by IAR. Please consider raising this question directly with them as I am not aware how frequently they are watching CMSIS issues.

[ReinhardKeil]

@jlonnberg maybe you can help.

[RobinKastberg]

@SuperHeroAbner
We reasoned that it was better to follow C standard and we had an issue from a customer that wanted to allow usage of __NO_RETURN in strict language mode.

We can try to have another go here but it is hard to please everyone.

What are the benefits of having __NO_RETURN afterwards and what compatibility did we break? I recall something in trustedfirmware-m?