In the top lines of LPC17xx.h (CortexM3) I see several CortexM0 items. It seems to me they do not belong there.

For example: in enumIRQn there is a double entry of SysTick_IRQn

SysTick_IRQn Cortex-M0 System Tick Interrupt

SysTick_IRQn 15 Cortex-M3 System Tick Interrupt

Where is the file you're looking at? I'm not seeing it in my copy.

Click LPC17xx.h then look in Enumeration Type Documentation. May be only documentation is confusing?

(EDIT - about Igor complaining about not giving link): I did not even think about it. I also thought as being not possible. I even cannot do any text search or copy there. But I checked now in the online compiler, and indeed provides some kind of a link address; I cannot be sure if that would point to the required info. But.. I am sorry.

Finally found the link. Was it too hard to post it?

Looks like a doc generator bug. If you click "go to the source" you can see that there's no mention of M0.