feat: add display UI with splash screen, dashboard, and RSSI sparkline

Implement full SSD1306 OLED display support:
- Splash screen on boot (1.5s) with project name, version, board
- Dashboard showing radio state, config, counters, RSSI/SNR
- RSSI history sparkline (64-sample ring buffer, 2px-wide bars)
- DisplayOn/DisplayOff host commands routed via dedicated channel
- Pure render functions against generic DrawTarget (no hardware coupling)
- Display on/off control bypasses radio task entirely

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vendor/cortex-m-rt/tests/README.md

@@ -0,0 +1,7 @@
+# How to run
+
+To run the compile tests, use the following command on the root of the project:
+
+```
+cargo test --package cortex-m-rt --test compiletest --features device
+```

vendor/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-1.rs

@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+unsafe fn DefaultHandler(_irqn: i16, undef: u32) {}
+//~^ ERROR `DefaultHandler` must have signature `unsafe fn(i16) [-> !]`

vendor/cortex-m-rt/tests/compile-fail/default-handler-bad-signature-2.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+unsafe fn DefaultHandler(_irqn: i16) -> u32 {
+    //~^ ERROR `DefaultHandler` must have signature `unsafe fn(i16) [-> !]`
+    0
+}

vendor/cortex-m-rt/tests/compile-fail/default-handler-hidden.rs

@@ -0,0 +1,22 @@
+// 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_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::exception;
+
+    #[exception]
+    unsafe fn DefaultHandler(_irqn: i16) {}
+}

vendor/cortex-m-rt/tests/compile-fail/default-handler-twice.rs

@@ -0,0 +1,22 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+unsafe fn DefaultHandler(_irqn: i16) {}
+
+pub mod reachable {
+    use cortex_m_rt::exception;
+
+    #[exception] //~ ERROR symbol `DefaultHandler` is already defined
+    unsafe fn DefaultHandler(_irqn: i16) {}
+}

vendor/cortex-m-rt/tests/compile-fail/duplicate-static.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    UART0,
+}
+
+#[entry]
+fn foo() -> ! {
+    static mut X: u32 = 0;
+    static mut X: i32 = 0; //~ ERROR the name `X` is defined multiple times
+
+    loop {}
+}
+
+#[exception]
+fn SVCall() {
+    static mut X: u32 = 0;
+    static mut X: i32 = 0; //~ ERROR the name `X` is defined multiple times
+}
+
+#[interrupt]
+fn UART0() {
+    static mut X: u32 = 0;
+    static mut X: i32 = 0; //~ ERROR the name `X` is defined multiple times
+}

vendor/cortex-m-rt/tests/compile-fail/entry-args.rs

@@ -0,0 +1,12 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+
+#[entry(foo)] //~ ERROR This attribute accepts no arguments
+fn foo() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/entry-bad-signature-1.rs

@@ -0,0 +1,11 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+
+#[entry]
+fn foo() {}
+//~^ ERROR `#[entry]` function must have signature `[unsafe] fn() -> !`

vendor/cortex-m-rt/tests/compile-fail/entry-bad-signature-2.rs

@@ -0,0 +1,11 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+
+#[entry]
+fn foo(undef: i32) -> ! {}
+//~^ ERROR `#[entry]` function must have signature `[unsafe] fn() -> !`

vendor/cortex-m-rt/tests/compile-fail/entry-bad-signature-3.rs

@@ -0,0 +1,13 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+
+#[entry]
+extern "C" fn foo() -> ! {
+    //~^ ERROR `#[entry]` function must have signature `[unsafe] fn() -> !`
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/entry-hidden.rs

@@ -0,0 +1,19 @@
+// 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_halt;
+
+mod hidden {
+    use cortex_m_rt::entry;
+
+    // this function needs to be "reachable" (all modules between it and the crate root must be
+    // `pub`) or linking will fail
+    #[entry]
+    fn foo() -> ! { //~ ERROR function is never used
+        loop {}
+    }
+}

vendor/cortex-m-rt/tests/compile-fail/entry-soundness.rs

@@ -0,0 +1,26 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    static mut COUNT: u64 = 0;
+
+    loop {
+        if *COUNT % 2 == 0 {
+            *COUNT += 1;
+        } else {
+            *COUNT *= 2;
+        }
+    }
+}
+
+#[exception]
+fn SysTick() {
+    // If this was allowed it would lead to a data race as `SysTick` can preempt `foo`
+    foo(); //~ ERROR cannot find function `foo` in this scope
+}

vendor/cortex-m-rt/tests/compile-fail/entry-twice.rs

@@ -0,0 +1,17 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::entry;
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[entry] //~ ERROR symbol `main` is already defined
+fn bar() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/exception-args.rs

@@ -0,0 +1,15 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception(SysTick)] //~ ERROR This attribute accepts no arguments
+fn SysTick() {}

vendor/cortex-m-rt/tests/compile-fail/exception-bad-signature-1.rs

@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SysTick(undef: u32) {}
+//~^ ERROR `#[exception]` handlers other than `DefaultHandler` and `HardFault` must have signature `[unsafe] fn() [-> !]`

vendor/cortex-m-rt/tests/compile-fail/exception-bad-signature-2.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SysTick() -> u32 {
+    //~^ ERROR `#[exception]` handlers other than `DefaultHandler` and `HardFault` must have signature `[unsafe] fn() [-> !]`
+    0
+}

vendor/cortex-m-rt/tests/compile-fail/exception-hidden.rs

@@ -0,0 +1,22 @@
+// 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_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::exception;
+
+    #[exception]
+    fn SysTick() {}
+}

vendor/cortex-m-rt/tests/compile-fail/exception-nmi-unsafe.rs

@@ -0,0 +1,24 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn DefaultHandler(_irq: i16) {}
+//~^ ERROR defining a `DefaultHandler` is unsafe and requires an `unsafe fn`
+
+#[exception]
+fn HardFault() {}
+//~^ ERROR defining a `HardFault` handler is unsafe and requires an `unsafe fn`
+
+#[exception]
+fn NonMaskableInt() {}
+//~^ ERROR defining a `NonMaskableInt` handler is unsafe and requires an `unsafe fn`

vendor/cortex-m-rt/tests/compile-fail/exception-soundness.rs

@@ -0,0 +1,29 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SysTick() {
+    static mut COUNT: u64 = 0;
+
+    if *COUNT % 2 == 0 {
+        *COUNT += 1;
+    } else {
+        *COUNT *= 2;
+    }
+}
+
+#[exception]
+fn SVCall() {
+    // If this was allowed it would lead to a data race as `SVCall` could preempt `SysTick`
+    SysTick(); //~ ERROR cannot find function, tuple struct or tuple variant `SysTick` in this scope [E0425]
+}

vendor/cortex-m-rt/tests/compile-fail/exception-twice.rs

@@ -0,0 +1,22 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SysTick() {}
+
+pub mod reachable {
+    use cortex_m_rt::exception;
+
+    #[exception] //~ ERROR symbol `SysTick` is already defined
+    fn SysTick() {}
+}

vendor/cortex-m-rt/tests/compile-fail/exception-v8only.rs

@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+fn SecureFault() {}
+//~^ ERROR no variant or associated item named `SecureFault`

vendor/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-1.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+unsafe fn HardFault(_ef: &ExceptionFrame, undef: u32) -> ! {
+    //~^ ERROR `HardFault` handler must have signature `unsafe fn(&ExceptionFrame) -> !`
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-2.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception(trampoline = true)]
+unsafe fn HardFault() -> ! {
+    //~^ ERROR `HardFault` handler must have signature `unsafe fn(&ExceptionFrame) -> !`
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/hard-fault-bad-signature-3.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception(trampoline = false)]
+unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
+    //~^ ERROR `HardFault` handler must have signature `unsafe fn() -> !`
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/hard-fault-hidden.rs

@@ -0,0 +1,24 @@
+// 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_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+mod hidden {
+    use cortex_m_rt::{exception, ExceptionFrame};
+
+    #[exception]
+    fn HardFault(_ef: &ExceptionFrame) -> ! {
+        loop {}
+    }
+}

vendor/cortex-m-rt/tests/compile-fail/hard-fault-twice-mixed-trampoline.rs

@@ -0,0 +1,26 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception(trampoline = false)]
+unsafe fn HardFault() -> ! {
+    loop {}
+}
+
+pub mod reachable {
+    use cortex_m_rt::{exception, ExceptionFrame};
+
+    #[exception] //~ ERROR symbol `_HardFault` is already defined
+    unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
+        loop {}
+    }
+}

vendor/cortex-m-rt/tests/compile-fail/hard-fault-twice.rs

@@ -0,0 +1,26 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, ExceptionFrame};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[exception]
+unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
+    loop {}
+}
+
+pub mod reachable {
+    use cortex_m_rt::{exception, ExceptionFrame};
+
+    #[exception] //~ ERROR symbol `_HardFault` is already defined
+    unsafe fn HardFault(_ef: &ExceptionFrame) -> ! {
+        loop {}
+    }
+}

vendor/cortex-m-rt/tests/compile-fail/interrupt-args.rs

@@ -0,0 +1,20 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+}
+
+#[interrupt(true)] //~ ERROR This attribute accepts no arguments
+fn USART1() {}

vendor/cortex-m-rt/tests/compile-fail/interrupt-bad-signature-1.rs

@@ -0,0 +1,21 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+}
+
+#[interrupt]
+fn USART1(undef: i32) {}
+//~^ ERROR `#[interrupt]` handlers must have signature `[unsafe] fn() [-> !]`

vendor/cortex-m-rt/tests/compile-fail/interrupt-bad-signature-2.rs

@@ -0,0 +1,23 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+}
+
+#[interrupt]
+fn USART1() -> i32 {
+    //~^ ERROR `#[interrupt]` handlers must have signature `[unsafe] fn() [-> !]`
+    0
+}

vendor/cortex-m-rt/tests/compile-fail/interrupt-invalid.rs

@@ -0,0 +1,22 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn entry() -> ! {
+    loop {}
+}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+}
+
+// NOTE this looks a bit better when using a device crate:
+// "no variant named `foo` found for type `stm32f30x::Interrupt` in the current scope"
+#[interrupt]
+fn foo() {} //~ ERROR no variant or associated item named `foo` found for enum `interrupt` in the current scope [E0599]

vendor/cortex-m-rt/tests/compile-fail/interrupt-not-reexported.rs

@@ -0,0 +1,15 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[interrupt] //~ ERROR failed to resolve: use of undeclared crate or module `interrupt`
+fn USART1() {}

vendor/cortex-m-rt/tests/compile-fail/interrupt-soundness.rs

@@ -0,0 +1,34 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+    USART2,
+}
+
+#[interrupt]
+fn USART1() {
+    static mut COUNT: u64 = 0;
+
+    if *COUNT % 2 == 0 {
+        *COUNT += 1;
+    } else {
+        *COUNT *= 2;
+    }
+}
+
+#[interrupt]
+fn USART2() {
+    USART1(); //~ ERROR cannot find function, tuple struct or tuple variant `USART1` in this scope [E0425]
+}

vendor/cortex-m-rt/tests/compile-fail/interrupt-twice.rs

@@ -0,0 +1,31 @@
+#![allow(non_camel_case_types)]
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, interrupt};
+
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+enum interrupt {
+    USART1,
+}
+
+#[interrupt]
+fn USART1() {}
+
+pub mod reachable {
+    use cortex_m_rt::interrupt;
+
+    enum interrupt {
+        USART1,
+    }
+
+    #[interrupt] //~ ERROR symbol `USART1` is already defined
+    fn USART1() {}
+}

vendor/cortex-m-rt/tests/compile-fail/non-static-resource.rs

@@ -0,0 +1,44 @@
+//! Tests that no `&'static mut` to static mutable resources can be obtained, which would be
+//! unsound.
+//!
+//! Regression test for https://github.com/rust-embedded/cortex-m-rt/issues/212
+
+#![no_std]
+#![no_main]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt, ExceptionFrame};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    UART0,
+}
+
+#[exception]
+fn SVCall() {
+    static mut STAT: u8 = 0;
+
+    let _stat: &'static mut u8 = STAT;
+    //~^ ERROR lifetime may not live long enough
+}
+
+#[interrupt]
+fn UART0() {
+    static mut STAT: u8 = 0;
+
+    let _stat: &'static mut u8 = STAT;
+    //~^ ERROR lifetime may not live long enough
+}
+
+#[entry]
+fn you_died_of_dis_entry() -> ! {
+    static mut STAT: u8 = 0;
+
+    // Allowed. This is sound for the entry point since it is only ever called once, and it makes
+    // resources far more useful.
+    let _stat: &'static mut u8 = STAT;
+
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/pre-init-args.rs

@@ -0,0 +1,15 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init(foo)] //~ ERROR This attribute accepts no arguments
+unsafe fn foo() {}
+
+#[entry]
+fn baz() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-1.rs

@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init]
+fn foo() {}
+//~^ ERROR `#[pre_init]` function must have signature `unsafe fn()`
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/pre-init-bad-signature-2.rs

@@ -0,0 +1,16 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init]
+unsafe fn foo(undef: i32) {}
+//~^ ERROR `#[pre_init]` function must have signature `unsafe fn()`
+
+#[entry]
+fn bar() -> ! {
+    loop {}
+}

vendor/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_halt;
+
+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 {}
+}

vendor/cortex-m-rt/tests/compile-fail/pre-init-twice.rs

@@ -0,0 +1,18 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, pre_init};
+
+#[pre_init]
+unsafe fn foo() {}
+
+#[pre_init] //~ ERROR symbol `__pre_init` is already defined
+unsafe fn bar() {}
+
+#[entry]
+fn baz() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compile-fail/unsafe-init-static.rs

@@ -0,0 +1,45 @@
+//! Makes sure that the expansion of the attributes doesn't put the resource initializer in an
+//! implicit `unsafe` block.
+
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    UART0,
+}
+
+const unsafe fn init() -> u32 { 0 }
+
+#[entry]
+fn foo() -> ! {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+
+    loop {}
+}
+
+#[exception]
+fn SVCall() {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}
+
+#[exception]
+unsafe fn DefaultHandler(_irq: i16) {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}
+
+#[exception]
+unsafe fn HardFault(_frame: &cortex_m_rt::ExceptionFrame) -> ! {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+    loop {}
+}
+
+#[interrupt]
+fn UART0() {
+    static mut X: u32 = init();  //~ ERROR requires unsafe
+}

vendor/cortex-m-rt/tests/compile-fail/whitelist-1.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[inline] //~ ERROR this attribute is not allowed on a cortex-m-rt entry point
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[inline] //~ ERROR this attribute is not allowed on an exception handler controlled by cortex-m-rt
+#[exception]
+fn SysTick() {}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+    USART2,
+}
+
+#[inline] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART1() {}
+
+#[cfg(feature = "device")]
+#[cfg_attr(feature = "device", inline)] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART2() {}

vendor/cortex-m-rt/tests/compile-fail/whitelist-2.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[export_name = "not_allowed"] //~ ERROR this attribute is not allowed on a cortex-m-rt entry point
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[export_name = "not_allowed"] //~ ERROR this attribute is not allowed on an exception handler controlled by cortex-m-rt
+#[exception]
+fn SysTick() {}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+    USART2,
+}
+
+#[export_name = "not_allowed"] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART1() {}
+
+#[cfg(feature = "device")]
+#[cfg_attr(feature = "device", export_name = "not_allowed")] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART2() {}

vendor/cortex-m-rt/tests/compile-fail/whitelist-3.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[no_mangle] //~ ERROR this attribute is not allowed on a cortex-m-rt entry point
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[no_mangle] //~ ERROR this attribute is not allowed on an exception handler controlled by cortex-m-rt
+#[exception]
+fn SysTick() {}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+    USART2,
+}
+
+#[no_mangle] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART1() {}
+
+#[cfg(feature = "device")]
+#[cfg_attr(feature = "device", no_mangle)] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART2() {}

vendor/cortex-m-rt/tests/compile-fail/whitelist-4.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception, interrupt};
+
+#[must_use] //~ ERROR this attribute is not allowed on a cortex-m-rt entry point
+#[entry]
+fn foo() -> ! {
+    loop {}
+}
+
+#[must_use] //~ ERROR this attribute is not allowed on an exception handler controlled by cortex-m-rt
+#[exception]
+fn SysTick() {}
+
+#[allow(non_camel_case_types)]
+enum interrupt {
+    USART1,
+    USART2,
+}
+
+#[must_use] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART1() {}
+
+#[cfg(feature = "device")]
+#[cfg_attr(feature = "device", must_use)] //~ ERROR this attribute is not allowed on an interrupt handler controlled by cortex-m-rt
+#[interrupt]
+fn USART2() {}

vendor/cortex-m-rt/tests/compile-fail/whitelist-double-attr.rs

@@ -0,0 +1,13 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt;
+extern crate panic_halt;
+
+use cortex_m_rt::{entry, exception};
+
+#[exception]
+#[entry] //~ ERROR this attribute is not allowed on an exception handler
+fn SVCall() -> ! {
+    loop {}
+}

vendor/cortex-m-rt/tests/compiletest.rs

@@ -0,0 +1,22 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::Config::default();
+
+    config.mode = mode.parse().expect("Invalid mode");
+    config.src_base = PathBuf::from(format!("tests/{}", mode));
+    config.target_rustcflags = Some(
+        "-L ../target/debug -L ../target/debug/deps -C panic=abort --cfg feature=\"device\""
+            .to_owned(),
+    );
+    config.clean_rmeta(); // If your tests import the parent crate, this helps with E0464
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+}