forbid early returns in init

tests/cfail/early-return-2.rs

@@ -0,0 +1,29 @@
+#![no_main]
+#![no_std]
+
+extern crate lm3s6965;
+extern crate panic_halt;
+extern crate rtfm;
+
+use rtfm::app;
+
+#[app(device = lm3s6965)]
+const APP: () = {
+    static mut UNINITIALIZED: bool = ();
+
+    #[init]
+    fn init() {
+        if false {
+            return; //~ ERROR `init` is *not* allowed to early return
+        }
+
+        UNINITIALIZED = true;
+    }
+
+    #[interrupt(resources = [UNINITIALIZED])]
+    fn UART0() {
+        if resources.UNINITIALIZED {
+            // UB
+        }
+    }
+};

tests/cfail/early-return.rs

@@ -0,0 +1,32 @@
+#![no_main]
+#![no_std]
+
+extern crate lm3s6965;
+extern crate panic_halt;
+extern crate rtfm;
+
+use rtfm::app;
+
+#[app(device = lm3s6965)]
+const APP: () = {
+    static mut UNINITIALIZED: bool = ();
+
+    #[init]
+    fn init() {
+        let x = || {
+            // this is OK
+            return 0;
+        };
+
+        return; //~ ERROR `init` is *not* allowed to early return
+
+        UNINITIALIZED = true;
+    }
+
+    #[interrupt(resources = [UNINITIALIZED])]
+    fn UART0() {
+        if resources.UNINITIALIZED {
+            // UB
+        }
+    }
+};