add compile-fail tests; test only on nightly

we'll test on beta when 1.30-beta is out

1 files changed, 23 insertions, 0 deletions

diff --git a/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs b/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs
new file mode 100644
index 0000000..f512d62
--- /dev/null
+++ b/cortex-m-rt/tests/compile-fail/pre-init-hidden.rs
@@ -0,0 +1,23 @@
+// ignore-test :sadface: it's not possible to prevent this user error at compile time
+// see rust-lang/rust#53975 for details
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_semihosting;
+
+mod hidden {
+    use cortex_m_rt::pre_init;
+
+    // this function needs to be "reachable" (all modules between it and the crate root must be
+    // `pub`) or the function will be ignored
+    #[entry]
+    unsafe fn pre_init() {} //~ ERROR function is never used
+}
+
+#[entry]
+fn foo() -> ! {
+    //~ ERROR function is never used
+    loop {}
+}