Add a test that enables ALL the warnings

Cargo.toml

@@ -31,6 +31,10 @@ compiletest_rs = "0.4.0"
 name = "device"
 required-features = ["device"]
 
+[[example]]
+name = "warnings"
+required-features = ["device"]
+
 [[test]]
 name = "compiletest"
 required-features = ["device"]

examples/warnings.rs

@@ -0,0 +1,50 @@
+//! Tests that a crate can still build with all warnings enabled.
+//!
+//! The code generated by the `cortex-m-rt` macros might need to manually
+//! `#[allow]` some of them (even though Rust does that by default for a few
+//! warnings too).
+
+#![no_std]
+#![no_main]
+#![deny(warnings, missing_docs, rust_2018_idioms)]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt, pre_init, ExceptionFrame};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    INT,
+}
+
+extern "C" {
+    fn INT();
+}
+
+union Vector {
+    #[allow(dead_code)]
+    handler: unsafe extern "C" fn(),
+}
+
+#[link_section = ".vector_table.interrupts"]
+#[no_mangle]
+#[used]
+static __INTERRUPTS: [Vector; 1] = [Vector { handler: INT }];
+
+/// Dummy interrupt.
+#[interrupt]
+fn INT() {}
+
+#[exception]
+fn HardFault(_eh: &ExceptionFrame) -> ! {
+    loop {}
+}
+
+#[entry]
+fn main() -> ! {
+    loop {}
+}
+
+#[pre_init]
+unsafe fn pre_init() {}