Now late resources are always used

35 files changed, 125 insertions, 71 deletions

diff --git a/examples/baseline.rs b/examples/baseline.rs
index f46b273d..5a6dbd4c 100644
--- a/examples/baseline.rs
+++ b/examples/baseline.rs
@@ -13,13 +13,15 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
 const APP: () = {
     #[init(spawn = [foo])]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         // omitted: initialization of `CYCCNT`
 
         hprintln!("init(baseline = {:?})", cx.start).unwrap();
 
         // `foo` inherits the baseline of `init`: `Instant(0)`
         cx.spawn.foo().unwrap();
+
+        init::LateResources {}
     }
 
     #[task(schedule = [foo])]
diff --git a/examples/binds.rs b/examples/binds.rs
index 82bf8964..f3ce51ec 100644
--- a/examples/binds.rs
+++ b/examples/binds.rs
@@ -13,10 +13,12 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::UART0);
 
         hprintln!("init").unwrap();
+
+        init::LateResources {}
     }
 
     #[idle]
diff --git a/examples/capacity.rs b/examples/capacity.rs
index 00cec344..cac0029c 100644
--- a/examples/capacity.rs
+++ b/examples/capacity.rs
@@ -12,8 +12,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::UART0);
+
+        init::LateResources {}
     }
 
     #[task(binds = UART0, spawn = [foo, bar])]
diff --git a/examples/cfg.rs b/examples/cfg.rs
index 8eeeb2a9..4f467247 100644
--- a/examples/cfg.rs
+++ b/examples/cfg.rs
@@ -19,9 +19,11 @@ const APP: () = {
     }
 
     #[init(spawn = [foo])]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         cx.spawn.foo().unwrap();
         cx.spawn.foo().unwrap();
+
+        init::LateResources {}
     }
 
     #[idle]
diff --git a/examples/destructure.rs b/examples/destructure.rs
index 1756bd9e..ad1d8594 100644
--- a/examples/destructure.rs
+++ b/examples/destructure.rs
@@ -22,9 +22,11 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::UART0);
         rtic::pend(Interrupt::UART1);
+
+        init::LateResources {}
     }
 
     // Direct destructure
diff --git a/examples/generics.rs b/examples/generics.rs
index 40ab81ac..65c5db02 100644
--- a/examples/generics.rs
+++ b/examples/generics.rs
@@ -18,9 +18,11 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::UART0);
         rtic::pend(Interrupt::UART1);
+
+        init::LateResources {}
     }
 
     #[task(binds = UART0, resources = [shared])]
diff --git a/examples/hardware.rs b/examples/hardware.rs
index 8105a742..30de77ab 100644
--- a/examples/hardware.rs
+++ b/examples/hardware.rs
@@ -12,12 +12,14 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         // Pends the UART0 interrupt but its handler won't run until *after*
         // `init` returns because interrupts are disabled
         rtic::pend(Interrupt::UART0); // equivalent to NVIC::pend
 
         hprintln!("init").unwrap();
+
+        init::LateResources {}
     }
 
     #[idle]
diff --git a/examples/idle.rs b/examples/idle.rs
index 3d28dac8..b029fcae 100644
--- a/examples/idle.rs
+++ b/examples/idle.rs
@@ -11,8 +11,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         hprintln!("init").unwrap();
+
+        init::LateResources {}
     }
 
     #[idle]
diff --git a/examples/init.rs b/examples/init.rs
index 315969f0..d5cebbaa 100644
--- a/examples/init.rs
+++ b/examples/init.rs
@@ -11,7 +11,7 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965, peripherals = true)]
 const APP: () = {
     #[init]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         static mut X: u32 = 0;
 
         // Cortex-M peripherals
@@ -26,5 +26,7 @@ const APP: () = {
         hprintln!("init").unwrap();
 
         debug::exit(debug::EXIT_SUCCESS);
+
+        init::LateResources {}
     }
 };
diff --git a/examples/lock.rs b/examples/lock.rs
index 5e3bce25..ff947c53 100644
--- a/examples/lock.rs
+++ b/examples/lock.rs
@@ -17,8 +17,10 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::GPIOA);
+
+        init::LateResources {}
     }
 
     // when omitted priority is assumed to be `1`
diff --git a/examples/message.rs b/examples/message.rs
index 596f2449..a1352c0e 100644
--- a/examples/message.rs
+++ b/examples/message.rs
@@ -11,8 +11,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init(spawn = [foo])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         c.spawn.foo(/* no message */).unwrap();
+
+        init::LateResources {}
     }
 
     #[task(spawn = [bar])]
diff --git a/examples/not-send.rs b/examples/not-send.rs
index 16a874dc..999abfaf 100644
--- a/examples/not-send.rs
+++ b/examples/not-send.rs
@@ -23,9 +23,11 @@ const APP: () = {
     }
 
     #[init(spawn = [baz, quux])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         c.spawn.baz().unwrap();
         c.spawn.quux().unwrap();
+
+        init::LateResources {}
     }
 
     #[task(spawn = [bar])]
diff --git a/examples/not-sync.rs b/examples/not-sync.rs
index a7eaac8e..5a67489f 100644
--- a/examples/not-sync.rs
+++ b/examples/not-sync.rs
@@ -22,8 +22,10 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         debug::exit(debug::EXIT_SUCCESS);
+
+        init::LateResources {}
     }
 
     #[task(resources = [&shared])]
diff --git a/examples/periodic.rs b/examples/periodic.rs
index 405346e3..da56d468 100644
--- a/examples/periodic.rs
+++ b/examples/periodic.rs
@@ -15,10 +15,12 @@ const PERIOD: u32 = 8_000_000;
 #[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
 const APP: () = {
     #[init(schedule = [foo])]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         // omitted: initialization of `CYCCNT`
 
         cx.schedule.foo(cx.start + PERIOD.cycles()).unwrap();
+
+        init::LateResources {}
     }
 
     #[task(schedule = [foo])]
diff --git a/examples/peripherals-taken.rs b/examples/peripherals-taken.rs
index cd4ba0f0..42ad8c0f 100644
--- a/examples/peripherals-taken.rs
+++ b/examples/peripherals-taken.rs
@@ -9,8 +9,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn main(_: main::Context) {
+    fn main(_: main::Context) -> main::LateResources {
         assert!(cortex_m::Peripherals::take().is_none());
         debug::exit(debug::EXIT_SUCCESS);
+
+        main::LateResources {}
     }
 };
diff --git a/examples/pool.rs b/examples/pool.rs
index 824d5bd8..9fccdf84 100644
--- a/examples/pool.rs
+++ b/examples/pool.rs
@@ -20,13 +20,15 @@ pool!(P: [u8; 128]);
 #[app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         static mut MEMORY: [u8; 512] = [0; 512];
 
         // Increase the capacity of the memory pool by ~4
         P::grow(MEMORY);
 
         rtic::pend(Interrupt::I2C0);
+
+        init::LateResources {}
     }
 
     #[task(binds = I2C0, priority = 2, spawn = [foo, bar])]
diff --git a/examples/preempt.rs b/examples/preempt.rs
index 3cb11029..7103b17b 100644
--- a/examples/preempt.rs
+++ b/examples/preempt.rs
@@ -11,8 +11,10 @@ use rtic::app;
 #[app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::GPIOA);
+
+        init::LateResources {}
     }
 
     #[task(binds = GPIOA, priority = 1)]
diff --git a/examples/ramfunc.rs b/examples/ramfunc.rs
index 1f95d496..214b7e67 100644
--- a/examples/ramfunc.rs
+++ b/examples/ramfunc.rs
@@ -11,8 +11,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init(spawn = [bar])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         c.spawn.bar().unwrap();
+
+        init::LateResources {}
     }
 
     #[inline(never)]
diff --git a/examples/resource.rs b/examples/resource.rs
index 2361fd00..06aa9756 100644
--- a/examples/resource.rs
+++ b/examples/resource.rs
@@ -18,9 +18,11 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         rtic::pend(Interrupt::UART0);
         rtic::pend(Interrupt::UART1);
+
+        init::LateResources {}
     }
 
     // `shared` cannot be accessed from this context
diff --git a/examples/schedule.rs b/examples/schedule.rs
index 70a7a5e3..b76d9e7f 100644
--- a/examples/schedule.rs
+++ b/examples/schedule.rs
@@ -14,7 +14,7 @@ use rtic::cyccnt::{Instant, U32Ext as _};
 #[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
 const APP: () = {
     #[init(schedule = [foo, bar])]
-    fn init(mut cx: init::Context) {
+    fn init(mut cx: init::Context) -> init::LateResources {
         // Initialize (enable) the monotonic timer (CYCCNT)
         cx.core.DCB.enable_trace();
         // required on Cortex-M7 devices that software lock the DWT (e.g. STM32F7)
@@ -32,6 +32,8 @@ const APP: () = {
 
         // Schedule `bar` to run 4e6 cycles in the future
         cx.schedule.bar(now + 4_000_000.cycles()).unwrap();
+
+        init::LateResources {}
     }
 
     #[task]
diff --git a/examples/shared-with-init.rs b/examples/shared-with-init.rs
index bd55f7ef..fa900a26 100644
--- a/examples/shared-with-init.rs
+++ b/examples/shared-with-init.rs
@@ -20,12 +20,14 @@ const APP: () = {
     }
 
     #[init(resources = [shared])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         // this `message` will be sent to task `UART0`
         let message = MustBeSend;
         *c.resources.shared = Some(message);
 
         rtic::pend(Interrupt::UART0);
+
+        init::LateResources {}
     }
 
     #[task(binds = UART0, resources = [shared])]
diff --git a/examples/t-binds.rs b/examples/t-binds.rs
index 588ac46f..edf0fc69 100644
--- a/examples/t-binds.rs
+++ b/examples/t-binds.rs
@@ -10,7 +10,9 @@ use panic_halt as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {}
+    fn init(_: init::Context) -> init::LateResources {
+        init::LateResources {}
+    }
 
     // Cortex-M exception
     #[task(binds = SVCall)]
diff --git a/examples/t-cfg.rs b/examples/t-cfg.rs
index b6c9e472..254cb8e0 100644
--- a/examples/t-cfg.rs
+++ b/examples/t-cfg.rs
@@ -14,9 +14,11 @@ const APP: () = {
     }
 
     #[init]
-    fn init(_: init::Context) {
+    fn init(_: init::Context) -> init::LateResources {
         #[cfg(never)]
         static mut BAR: u32 = 0;
+
+        init::LateResources {}
     }
 
     #[idle]
diff --git a/examples/t-htask-main.rs b/examples/t-htask-main.rs
index c4bebf94..885019a1 100644
--- a/examples/t-htask-main.rs
+++ b/examples/t-htask-main.rs
@@ -9,8 +9,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {
-        rtic::pend(lm3s6965::Interrupt::UART0)
+    fn init(_: init::Context) -> init::LateResources {
+        rtic::pend(lm3s6965::Interrupt::UART0);
+
+        init::LateResources {}
     }
 
     #[task(binds = UART0)]
diff --git a/examples/t-idle-main.rs b/examples/t-idle-main.rs
index 051a9ee8..3e06cac6 100644
--- a/examples/t-idle-main.rs
+++ b/examples/t-idle-main.rs
@@ -9,7 +9,9 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn init(_: init::Context) {}
+    fn init(_: init::Context) -> init::LateResources {
+        init::LateResources {}
+    }
 
     #[idle]
     fn main(_: main::Context) -> ! {
diff --git a/examples/t-init-main.rs b/examples/t-init-main.rs
index 6a6cd991..f6c1d9ca 100644
--- a/examples/t-init-main.rs
+++ b/examples/t-init-main.rs
@@ -9,7 +9,9 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init]
-    fn main(_: main::Context) {
+    fn main(_: main::Context) -> main::LateResources {
         debug::exit(debug::EXIT_SUCCESS);
+
+        main::LateResources {}
     }
 };
diff --git a/examples/t-resource.rs b/examples/t-resource.rs
index 81ba1856..78e518c1 100644
--- a/examples/t-resource.rs
+++ b/examples/t-resource.rs
@@ -31,7 +31,7 @@ const APP: () = {
     }
 
     #[init(resources = [o1, o4, o5, o6, s3])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         // owned by `init` == `&'static mut`
         let _: &'static mut u32 = c.resources.o1;
 
@@ -42,6 +42,8 @@ const APP: () = {
         let _: &mut u32 = c.resources.o4;
         let _: &mut u32 = c.resources.o5;
         let _: &mut u32 = c.resources.s3;
+
+        init::LateResources {}
     }
 
     #[idle(resources = [o2, &o4, s1, &s3])]
diff --git a/examples/t-schedule.rs b/examples/t-schedule.rs
index 3854aad3..8af01aba 100644
--- a/examples/t-schedule.rs
+++ b/examples/t-schedule.rs
@@ -11,10 +11,12 @@ use rtic::cyccnt::{Instant, U32Ext as _};
 #[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
 const APP: () = {
     #[init(schedule = [foo, bar, baz])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         let _: Result<(), ()> = c.schedule.foo(c.start + 10.cycles());
         let _: Result<(), u32> = c.schedule.bar(c.start + 20.cycles(), 0);
         let _: Result<(), (u32, u32)> = c.schedule.baz(c.start + 30.cycles(), 0, 1);
+
+        init::LateResources {}
     }
 
     #[idle(schedule = [foo, bar, baz])]
diff --git a/examples/t-spawn.rs b/examples/t-spawn.rs
index 35831ccf..af2a79ea 100644
--- a/examples/t-spawn.rs
+++ b/examples/t-spawn.rs
@@ -10,10 +10,12 @@ use panic_halt as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init(spawn = [foo, bar, baz])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         let _: Result<(), ()> = c.spawn.foo();
         let _: Result<(), u32> = c.spawn.bar(0);
         let _: Result<(), (u32, u32)> = c.spawn.baz(0, 1);
+
+        init::LateResources {}
     }
 
     #[idle(spawn = [foo, bar, baz])]
diff --git a/examples/t-stask-main.rs b/examples/t-stask-main.rs
index f2709404..aefd4821 100644
--- a/examples/t-stask-main.rs
+++ b/examples/t-stask-main.rs
@@ -9,8 +9,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init(spawn = [main])]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         cx.spawn.main().ok();
+
+        init::LateResources {}
     }
 
     #[task]
diff --git a/examples/task.rs b/examples/task.rs
index 12c4ac83..e148b356 100644
--- a/examples/task.rs
+++ b/examples/task.rs
@@ -11,8 +11,10 @@ use panic_semihosting as _;
 #[rtic::app(device = lm3s6965)]
 const APP: () = {
     #[init(spawn = [foo])]
-    fn init(c: init::Context) {
+    fn init(c: init::Context) -> init::LateResources {
         c.spawn.foo().unwrap();
+
+        init::LateResources {}
     }
 
     #[task(spawn = [bar, baz])]
diff --git a/examples/types.rs b/examples/types.rs
index 5233f868..46d08b83 100644
--- a/examples/types.rs
+++ b/examples/types.rs
@@ -17,7 +17,7 @@ const APP: () = {
     }
 
     #[init(schedule = [foo], spawn = [foo])]
-    fn init(cx: init::Context) {
+    fn init(cx: init::Context) -> init::LateResources {
         let _: cyccnt::Instant = cx.start;
         let _: rtic::Peripherals = cx.core;
         let _: lm3s6965::Peripherals = cx.device;
@@ -25,6 +25,8 @@ const APP: () = {
         let _: init::Spawn = cx.spawn;
 
         debug::exit(debug::EXIT_SUCCESS);
+
+        init::LateResources {}
     }
 
     #[idle(schedule = [foo], spawn = [foo])]
diff --git a/macros/Cargo.toml b/macros/Cargo.toml
index 610890bb..ec5c130c 100644
--- a/macros/Cargo.toml
+++ b/macros/Cargo.toml
@@ -21,5 +21,5 @@ proc-macro = true
 proc-macro2 = "1"
 quote = "1"
 syn = "1"
-rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "master", version = "0.4.0" }
+rtic-syntax = { git = "https://github.com/rtic-rs/rtic-syntax", branch = "always_late_resources" }
 
diff --git a/macros/src/codegen/init.rs b/macros/src/codegen/init.rs
index e0b7d699..b41c3894 100644
--- a/macros/src/codegen/init.rs
+++ b/macros/src/codegen/init.rs
@@ -34,39 +34,31 @@ pub fn codegen(
 
         let mut root_init = vec![];
 
-        let ret = {
-            let late_fields = analysis
-                .late_resources
-                .iter()
-                .flat_map(|resources| {
-                    resources.iter().map(|name| {
-                        let ty = &app.late_resources[name].ty;
-                        let cfgs = &app.late_resources[name].cfgs;
-
-                        quote!(
-                        #(#cfgs)*
-                        pub #name: #ty
-                        )
-                    })
+        let late_fields = analysis
+            .late_resources
+            .iter()
+            .flat_map(|resources| {
+                resources.iter().map(|name| {
+                    let ty = &app.late_resources[name].ty;
+                    let cfgs = &app.late_resources[name].cfgs;
+
+                    quote!(
+                    #(#cfgs)*
+                    pub #name: #ty
+                    )
                 })
-                .collect::<Vec<_>>();
-
-            if !late_fields.is_empty() {
-                let late_resources = util::late_resources_ident(&name);
+            })
+            .collect::<Vec<_>>();
 
-                root_init.push(quote!(
-                    /// Resources initialized at runtime
-                    #[allow(non_snake_case)]
-                    pub struct #late_resources {
-                        #(#late_fields),*
-                    }
-                ));
+        let late_resources = util::late_resources_ident(&name);
 
-                Some(quote!(-> #name::LateResources))
-            } else {
-                None
+        root_init.push(quote!(
+            /// Resources initialized at runtime
+            #[allow(non_snake_case)]
+            pub struct #late_resources {
+                #(#late_fields),*
             }
-        };
+        ));
 
         let mut locals_pat = None;
         let mut locals_new = None;
@@ -85,7 +77,7 @@ pub fn codegen(
         let user_init = Some(quote!(
             #(#attrs)*
             #[allow(non_snake_case)]
-            fn #name(#(#locals_pat,)* #context: #name::Context) #ret {
+            fn #name(#(#locals_pat,)* #context: #name::Context) -> #name::LateResources {
                 #(#stmts)*
             }
         ));
diff --git a/macros/src/codegen/module.rs b/macros/src/codegen/module.rs
index 863f6c5b..85bab3ab 100644
--- a/macros/src/codegen/module.rs
+++ b/macros/src/codegen/module.rs
@@ -253,14 +253,12 @@ pub fn codegen(ctxt: Context, resources_tick: bool, app: &App, extra: &Extra) ->
 
     if let Context::Init = ctxt {
         let init = &app.inits.first().unwrap();
-        if init.returns_late_resources {
-            let late_resources = util::late_resources_ident(&init.name);
+        let late_resources = util::late_resources_ident(&init.name);
 
-            items.push(quote!(
-                #[doc(inline)]
-                pub use super::#late_resources as LateResources;
-            ));
-        }
+        items.push(quote!(
+            #[doc(inline)]
+            pub use super::#late_resources as LateResources;
+        ));
     }
 
     let doc = match ctxt {