extern crate cortex_m_rtfm as rtfm; use rtfm::{C2, C4, P1, P3, Resource}; static R1: Resource = Resource::new(0); static R2: Resource = Resource::new(0); fn j1(prio: P1) { R1.lock(&prio, |r1, _| { // Would preempt this critical section // rtfm::request(j2); }); } fn j2(prio: P3) { R2.lock(&prio, |r2, c4| { // OK C2 (R1's ceiling) <= C4 (system ceiling) // BAD C2 (R1's ceiling) < P3 (j2's priority) let r1 = R1.borrow(&prio, &c4); //~^ error }); }