compile time verified ceilings

tests/cfail.rs

@@ -0,0 +1,16 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+
+use compiletest::common::Mode;
+
+#[test]
+fn cfail() {
+    let mut config = compiletest::default_config();
+    config.mode = Mode::CompileFail;
+    config.src_base = PathBuf::from(format!("tests/cfail"));
+    config.target_rustcflags =
+        Some("-L target/debug -L target/debug/deps ".to_string());
+
+    compiletest::run_tests(&config);
+}

tests/cfail/borrow.rs

@@ -0,0 +1,22 @@
+extern crate cortex_m_srp;
+
+use cortex_m_srp::{C2, C3, C4, P1, Resource};
+
+static R1: Resource<i32, C3> = Resource::new(0);
+static R2: Resource<i32, C2> = Resource::new(0);
+static R3: Resource<i32, C3> = Resource::new(0);
+static R4: Resource<i32, C4> = Resource::new(0);
+
+fn j1(prio: P1) {
+    R1.lock(&prio, |r1, c3| {
+        // CAN borrow a resource with ceiling C when the system ceiling SC > C
+        let r2 = R2.borrow(&c3);
+
+        // CAN borrow a resource with ceiling C when the system ceiling SC == C
+        let r3 = R3.borrow(&c3);
+
+        // CAN'T borrow a resource with ceiling C when the system ceiling SC < C
+        let r4 = R4.borrow(&c3);
+        //~^ error
+    });
+}

tests/cfail/lock.rs

@@ -0,0 +1,41 @@
+extern crate cortex_m_srp;
+
+use cortex_m_srp::{C16, C2, P1, P16, P2, P3, Resource};
+
+static R1: Resource<i32, C2> = Resource::new(0);
+
+// You CAN'T lock a resource with ceiling C from a task with priority P if P > C
+fn j1(prio: P3) {
+    R1.lock(&prio, |_, _| {});
+    //~^ error
+}
+
+// DON'T lock a resource with ceiling equal to the task priority.
+// Instead use `claim`
+fn j2(prio: P2) {
+    R1.lock(&prio, |_, _| {});
+    //~^ error
+
+    // OK
+    let r1 = R1.claim(&prio);
+}
+
+// You CAN lock a resource with ceiling C from a task with priority P if C > P
+fn j3(prio: P1) {
+    // OK
+    R1.lock(&prio, |r1, _| {});
+}
+
+static R2: Resource<i32, C16> = Resource::new(0);
+
+// Tasks with priority less than P16 can't lock a resource with ceiling C16
+fn j4(prio: P1) {
+    R2.lock(&prio, |_, _| {});
+    //~^ error
+}
+
+// Only tasks with priority P16 can claim a resource with ceiling C16
+fn j5(prio: P16) {
+    // OK
+    let r2 = R2.claim(&prio);
+}