Auto merge of #58 - japaric:init-resources, r=japaric

safe `&'static mut` references via init.resources

see RFC #59 for details

.gitignore

@@ -1,5 +1,6 @@
 **/*.rs.bk
 *.org
+.#*
 .gdb_history
 Cargo.lock
 target/

Cargo.toml

@@ -15,11 +15,13 @@ version = "0.3.0"
 [dependencies]
 cortex-m = { git = "https://github.com/japaric/cortex-m" }
 untagged-option = "0.1.1"
-rtfm-core = "0.1.0"
+# rtfm-core = "0.2.0"
+rtfm-core = { git = "https://github.com/japaric/rtfm-core" }
 cortex-m-rtfm-macros = { path = "macros" }
 
 [target.'cfg(target_arch = "x86_64")'.dev-dependencies]
-compiletest_rs = "0.3.3"
+# compiletest_rs = "0.3.4"
+compiletest_rs = { git = "https://github.com/dwrensha/compiletest-rs", branch = "rustup" }
 
 [dev-dependencies.cortex-m-rt]
 features = ["abort-on-panic"]

examples/custom-type.rs

@@ -0,0 +1,50 @@
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![feature(proc_macro)]
+#![no_std]
+
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f103xx;
+
+use rtfm::{app, Threshold};
+
+pub struct Foo;
+
+app! {
+    device: stm32f103xx,
+
+    resources: {
+        static CO_OWNED: Foo = Foo;
+        static ON: Foo = Foo;
+        static OWNED: Foo = Foo;
+        static SHARED: Foo = Foo;
+    },
+
+    idle: {
+        resources: [OWNED, SHARED],
+    },
+
+    tasks: {
+        SYS_TICK: {
+            path: sys_tick,
+            resources: [CO_OWNED, ON, SHARED],
+        },
+
+        TIM2: {
+            enabled: false,
+            path: tim2,
+            priority: 1,
+            resources: [CO_OWNED],
+        },
+    },
+}
+
+fn init(_p: ::init::Peripherals, _r: ::init::Resources) {}
+
+fn idle(_t: &mut Threshold, _r: ::idle::Resources) -> ! {
+    loop {}
+}
+
+fn sys_tick(_t: &mut Threshold, _r: SYS_TICK::Resources) {}
+
+fn tim2(_t: &mut Threshold, _r: TIM2::Resources) {}

examples/full-syntax.rs

@@ -63,22 +63,22 @@ mod main {
             *r.OWNED != *r.OWNED;
 
             if *r.OWNED {
-                if r.SHARED.claim(t, |shared, _| **shared) {
+                if r.SHARED.claim(t, |shared, _| *shared) {
                     rtfm::wfi();
                 }
             } else {
-                r.SHARED.claim_mut(t, |shared, _| **shared = !**shared);
+                r.SHARED.claim_mut(t, |shared, _| *shared = !*shared);
             }
         }
     }
 }
 
-fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
+fn sys_tick(_t: &mut Threshold, mut r: SYS_TICK::Resources) {
-    **r.ON = !**r.ON;
+    *r.ON = !*r.ON;
 
-    **r.CO_OWNED += 1;
+    *r.CO_OWNED += 1;
 }
 
-fn tim2(_t: &mut Threshold, r: TIM2::Resources) {
+fn tim2(_t: &mut Threshold, mut r: TIM2::Resources) {
-    **r.CO_OWNED += 1;
+    *r.CO_OWNED += 1;
 }

examples/generics.rs

@@ -70,5 +70,5 @@ fn exti0(t: &mut Threshold, r: EXTI0::Resources) {
 
 // This task has direct access to the resources
 fn exti1(t: &mut Threshold, r: EXTI1::Resources) {
-    work(t, r.GPIOA, r.SPI1);
+    work(t, &r.GPIOA, &r.SPI1);
 }

examples/late-resources.rs

@@ -1,5 +1,4 @@
 //! Demonstrates initialization of resources in `init`.
-
 #![deny(unsafe_code)]
 #![deny(warnings)]
 #![feature(proc_macro)]

examples/one-task.rs

@@ -77,11 +77,11 @@ fn idle() -> ! {
 // `r` is the set of resources this task has access to. `SYS_TICK::Resources`
 // has one field per resource declared in `app!`.
 #[allow(unsafe_code)]
-fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
+fn sys_tick(_t: &mut Threshold, mut r: SYS_TICK::Resources) {
     // toggle state
-    **r.ON = !**r.ON;
+    *r.ON = !*r.ON;
 
-    if **r.ON {
+    if *r.ON {
         // set the pin PC13 high
         // NOTE(unsafe) atomic write to a stateless register
         unsafe {

examples/preemption.rs

@@ -42,12 +42,12 @@ fn idle() -> ! {
     }
 }
 
-fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
+fn sys_tick(_t: &mut Threshold, mut r: SYS_TICK::Resources) {
     // ..
 
     // This task can't be preempted by `tim2` so it has direct access to the
     // resource data
-    **r.COUNTER += 1;
+    *r.COUNTER += 1;
 
     // ..
 }
@@ -61,7 +61,7 @@ fn tim2(t: &mut Threshold, mut r: TIM2::Resources) {
     // lead to undefined behavior.
     r.COUNTER.claim_mut(t, |counter, _t| {
         // `claim_mut` creates a critical section
-        **counter += 1;
+        *counter += 1;
     });
 
     // ..

examples/safe-static-mut-ref.rs

@@ -0,0 +1,32 @@
+//! Safe creation of `&'static mut` references
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![feature(proc_macro)]
+#![no_std]
+
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f103xx;
+
+use rtfm::app;
+
+app! {
+    device: stm32f103xx,
+
+    resources: {
+        static BUFFER: [u8; 16] = [0; 16];
+    },
+
+    init: {
+        resources: [BUFFER],
+    },
+}
+
+fn init(_p: init::Peripherals, r: init::Resources) {
+    let _buf: &'static mut [u8] = r.BUFFER;
+}
+
+fn idle() -> ! {
+    loop {
+        rtfm::wfi();
+    }
+}

examples/two-tasks.rs

@@ -42,18 +42,18 @@ fn idle() -> ! {
 
 // As both tasks are running at the same priority one can't preempt the other.
 // Thus both tasks have direct access to the resource
-fn sys_tick(_t: &mut Threshold, r: SYS_TICK::Resources) {
+fn sys_tick(_t: &mut Threshold, mut r: SYS_TICK::Resources) {
     // ..
 
-    **r.COUNTER += 1;
+    *r.COUNTER += 1;
 
     // ..
 }
 
-fn tim2(_t: &mut Threshold, r: TIM2::Resources) {
+fn tim2(_t: &mut Threshold, mut r: TIM2::Resources) {
     // ..
 
-    **r.COUNTER += 1;
+    *r.COUNTER += 1;
 
     // ..
 }

macros/Cargo.toml

@@ -12,7 +12,8 @@ version = "0.2.1"
 [dependencies]
 error-chain = "0.10.0"
 quote = "0.3.15"
-rtfm-syntax = "0.2.0"
+# rtfm-syntax = "0.2.0"
+rtfm-syntax = { git = "https://github.com/japaric/rtfm-syntax" }
 syn = "0.11.11"
 
 [lib]

macros/src/analyze.rs

@@ -17,6 +17,13 @@ pub enum Ownership {
 }
 
 impl Ownership {
+    pub fn ceiling(&self) -> u8 {
+        match *self {
+            Ownership::Owned { priority } => priority,
+            Ownership::Shared { ceiling } => ceiling,
+        }
+    }
+
     pub fn is_owned(&self) -> bool {
         match *self {
             Ownership::Owned { .. } => true,

macros/src/check.rs

@@ -77,7 +77,38 @@ pub fn app(app: check::App) -> Result<App> {
 }
 
 fn resources(app: &App) -> Result<()> {
+    for name in &app.init.resources {
+        if let Some(resource) = app.resources.get(name) {
+            ensure!(
+                resource.expr.is_some(),
+                "resource `{}`, allocated to `init`, must have an initial value",
+                name
+            );
+        } else {
+            bail!(
+                "resource `{}`, allocated to `init`, must be a data resource",
+                name
+            );
+        }
+
+        ensure!(
+            !app.idle.resources.contains(name),
+            "resources assigned to `init` can't be shared with `idle`"
+        );
+
+        ensure!(
+            app.tasks
+                .iter()
+                .all(|(_, task)| !task.resources.contains(name)),
+            "resources assigned to `init` can't be shared with tasks"
+        )
+    }
+
     for resource in app.resources.keys() {
+        if app.init.resources.contains(resource) {
+            continue;
+        }
+
         if app.idle.resources.contains(resource) {
             continue;
         }

macros/src/trans.rs

@@ -1,7 +1,7 @@
 use quote::{Ident, Tokens};
 use syn::{Lit, StrStyle};
 
-use analyze::{Ownership, Ownerships};
+use analyze::Ownerships;
 use check::{App, Kind};
 
 fn krate() -> Ident {
@@ -81,11 +81,11 @@ fn idle(app: &App, ownerships: &Ownerships, main: &mut Vec<Tokens>, root: &mut V
                 });
             } else {
                 rfields.push(quote! {
-                    pub #name: #super_::_resource::#name,
+                    pub #name: ::idle::#name,
                 });
 
                 rexprs.push(quote! {
-                    #name: #super_::_resource::#name::new(),
+                    #name: ::idle::#name { _0: core::marker::PhantomData },
                 });
             }
         }
@@ -126,6 +126,85 @@ fn idle(app: &App, ownerships: &Ownerships, main: &mut Vec<Tokens>, root: &mut V
         exprs.push(quote!(unsafe { idle::Resources::new() }));
     }
 
+    let device = &app.device;
+    for name in &app.idle.resources {
+        let ceiling = ownerships[name].ceiling();
+
+        // owned resource
+        if ceiling == 0 {
+            continue
+        }
+
+        let _name = Ident::new(format!("_{}", name.as_ref()));
+        let resource = app.resources
+            .get(name)
+            .expect(&format!("BUG: resource {} has no definition", name));
+
+        let ty = &resource.ty;
+        let _static = if resource.expr.is_some() {
+            quote!(#_name)
+        } else {
+            quote!(#_name.some)
+        };
+
+        mod_items.push(quote! {
+            #[allow(non_camel_case_types)]
+            pub struct #name { _0: core::marker::PhantomData<*const ()> }
+        });
+
+        root.push(quote! {
+            #[allow(unsafe_code)]
+            unsafe impl #krate::Resource for idle::#name {
+                type Data = #ty;
+
+                fn borrow<'cs>(&'cs self, t: &'cs Threshold) -> &'cs Self::Data {
+                    assert!(t.value() >= #ceiling);
+
+                    unsafe { &#_static }
+                }
+
+                fn borrow_mut<'cs>(
+                    &'cs mut self,
+                    t: &'cs Threshold,
+                ) -> &'cs mut Self::Data {
+                    assert!(t.value() >= #ceiling);
+
+                    unsafe { &mut #_static }
+                }
+
+                fn claim<R, F>(&self, t: &mut Threshold, f: F) -> R
+                where
+                    F: FnOnce(&Self::Data, &mut Threshold) -> R
+                {
+                    unsafe {
+                        #krate::claim(
+                            &#_static,
+                            #ceiling,
+                            #device::NVIC_PRIO_BITS,
+                            t,
+                            f,
+                        )
+                    }
+                }
+
+                fn claim_mut<R, F>(&mut self, t: &mut Threshold, f: F) -> R
+                where
+                    F: FnOnce(&mut Self::Data, &mut Threshold) -> R
+                {
+                    unsafe {
+                        #krate::claim(
+                            &mut #_static,
+                            #ceiling,
+                            #device::NVIC_PRIO_BITS,
+                            t,
+                            f,
+                        )
+                    }
+                }
+            }
+        });
+    }
+
     if !mod_items.is_empty() {
         root.push(quote! {
             #[allow(unsafe_code)]
@@ -170,18 +249,30 @@ fn init(app: &App, main: &mut Vec<Tokens>, root: &mut Vec<Tokens>) {
         let mut rexprs = vec![];
 
         for (name, resource) in init_resources {
-            let _name = Ident::new(format!("_{}", name.as_ref()));
-            lifetime = Some(quote!('a));
-
             let ty = &resource.ty;
 
-            fields.push(quote! {
+            if app.init.resources.contains(name) {
-                pub #name: &'a mut #krate::Static<#ty>,
+                fields.push(quote! {
-            });
+                    pub #name: &'static mut #ty,
+                });
 
-            rexprs.push(quote! {
+                let expr = &resource.expr;
-                #name: ::#krate::Static::ref_mut(&mut ::#_name),
+                rexprs.push(quote!(#name: {
-            });
+                    static mut #name: #ty = #expr;
+                    &mut #name
+                },));
+            } else {
+                let _name = Ident::new(format!("_{}", name.as_ref()));
+                lifetime = Some(quote!('a));
+
+                fields.push(quote! {
+                    pub #name: &'a mut #ty,
+                });
+
+                rexprs.push(quote! {
+                    #name: &mut ::#_name,
+                });
+            }
         }
 
         root.push(quote! {
@@ -323,234 +414,153 @@ fn init(app: &App, main: &mut Vec<Tokens>, root: &mut Vec<Tokens>) {
 
 fn resources(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
     let krate = krate();
-    let device = &app.device;
 
-    let mut items = vec![];
+    for name in ownerships.keys() {
-    let mut impls = vec![];
-    for (name, ownership) in ownerships {
         let _name = Ident::new(format!("_{}", name.as_ref()));
 
-        if let Some(resource) = app.resources.get(name) {
+        // Declare the static that holds the resource
-            // Declare the static that holds the resource
+        let resource = app.resources
-            let expr = &resource.expr;
+            .get(name)
-            let ty = &resource.ty;
+            .expect(&format!("BUG: resource {} has no definition", name));
 
-            root.push(match *expr {
+        let expr = &resource.expr;
-                Some(ref expr) => quote! {
+        let ty = &resource.ty;
-                    static mut #_name: #ty = #expr;
-                },
-                None => quote! {
-                    // Resource initialized in `init`
-                    static mut #_name: #krate::UntaggedOption<#ty> = #krate::UntaggedOption { none: () };
-                },
-            });
-        }
 
-        let mut impl_items = vec![];
+        root.push(match *expr {
-
+            Some(ref expr) => quote! {
-        match *ownership {
+                static mut #_name: #ty = #expr;
-            Ownership::Owned { .. } => {
+            },
-                // For owned resources we don't need claim() or borrow()
+            None => quote! {
-            }
+                // Resource initialized in `init`
-            Ownership::Shared { ceiling } => {
+                static mut #_name: #krate::UntaggedOption<#ty> =
-                let resource = app.resources
+                    #krate::UntaggedOption { none: () };
-                    .get(name)
+            },
-                    .expect(&format!("BUG: resource {} has no definition", name));
+        });
-                let ty = &resource.ty;
-                let res_rvalue = if resource.expr.is_some() {
-                    quote!(#_name)
-                } else {
-                    quote!(#_name.some)
-                };
-
-                impl_items.push(quote! {
-                    type Data = #ty;
-
-                    fn borrow<'cs>(
-                        &'cs self,
-                        t: &'cs #krate::Threshold,
-                    ) -> &'cs #krate::Static<#ty> {
-                        assert!(t.value() >= #ceiling);
-
-                        unsafe { #krate::Static::ref_(&#res_rvalue) }
-                    }
-
-                    fn borrow_mut<'cs>(
-                        &'cs mut self,
-                        t: &'cs #krate::Threshold,
-                    ) -> &'cs mut #krate::Static<#ty> {
-                        assert!(t.value() >= #ceiling);
-
-                        unsafe {
-                            #krate::Static::ref_mut(&mut #res_rvalue)
-                        }
-                    }
-
-                    fn claim<R, F>(
-                        &self,
-                        t: &mut #krate::Threshold,
-                        f: F,
-                    ) -> R
-                    where
-                        F: FnOnce(
-                            &#krate::Static<#ty>,
-                            &mut #krate::Threshold) -> R
-                    {
-                        unsafe {
-                            #krate::claim(
-                                #krate::Static::ref_(&#res_rvalue),
-                                #ceiling,
-                                #device::NVIC_PRIO_BITS,
-                                t,
-                                f,
-                            )
-                        }
-                    }
-
-                    fn claim_mut<R, F>(
-                        &mut self,
-                        t: &mut #krate::Threshold,
-                        f: F,
-                    ) -> R
-                    where
-                        F: FnOnce(
-                            &mut #krate::Static<#ty>,
-                            &mut #krate::Threshold) -> R
-                    {
-                        unsafe {
-                            #krate::claim(
-                                #krate::Static::ref_mut(&mut #res_rvalue),
-                                #ceiling,
-                                #device::NVIC_PRIO_BITS,
-                                t,
-                                f,
-                            )
-                        }
-                    }
-                });
-
-                impls.push(quote! {
-                    #[allow(unsafe_code)]
-                    unsafe impl #krate::Resource for _resource::#name {
-                        #(#impl_items)*
-                    }
-                });
-
-                items.push(quote! {
-                    #[allow(non_camel_case_types)]
-                    pub struct #name { _0: PhantomData<*const ()> }
-
-                    #[allow(unsafe_code)]
-                    impl #name {
-                        pub unsafe fn new() -> Self {
-                            #name { _0: PhantomData }
-                        }
-                    }
-                });
-            }
-        }
     }
-
-    if !items.is_empty() {
-        root.push(quote! {
-            #[allow(unsafe_code)]
-            mod _resource {
-                use core::marker::PhantomData;
-
-                #(#items)*
-            }
-        })
-    }
-    root.push(quote! {
-        #(#impls)*
-    });
 }
 
 fn tasks(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
     let device = &app.device;
     let krate = krate();
 
-    for (name, task) in &app.tasks {
+    for (tname, task) in &app.tasks {
         let mut exprs = vec![];
         let mut fields = vec![];
         let mut items = vec![];
 
-        let mut lifetime = None;
-        let mut needs_reexport = false;
-        let mut needs_threshold = false;
         let has_resources = !task.resources.is_empty();
 
         if has_resources {
-            needs_threshold = !task.resources.is_empty();
+            for rname in &task.resources {
+                let ceiling = ownerships[rname].ceiling();
+                let _rname = Ident::new(format!("_{}", rname.as_ref()));
+                let resource = app.resources
+                    .get(rname)
+                    .expect(&format!("BUG: resource {} has no definition", rname));
 
-            for name in &task.resources {
+                let ty = &resource.ty;
-                let _name = Ident::new(format!("_{}", name.as_ref()));
+                let _static = if resource.expr.is_some() {
+                    quote!(#_rname)
+                } else {
+                    quote!(#_rname.some)
+                };
 
-                match ownerships[name] {
+                items.push(quote! {
-                    Ownership::Shared { ceiling } if ceiling > task.priority => {
-                        needs_threshold = true;
-
-                        fields.push(quote! {
-                            pub #name: ::_resource::#name,
-                        });
-
-                        exprs.push(quote! {
-                            #name: {
-                                ::_resource::#name::new()
-                            },
-                        });
-                    }
-                    _ => {
-                        lifetime = Some(quote!('a));
-                        let resource = app.resources
-                            .get(name)
-                            .expect(&format!("BUG: resource {} has no definition", name));
-
-                        needs_reexport = true;
-                        let ty = &resource.ty;
-
-                        fields.push(quote! {
-                            pub #name: &'a mut ::#krate::Static<#ty>,
-                        });
-
-                        exprs.push(if resource.expr.is_some() {
-                            quote! {
-                                #name: ::#krate::Static::ref_mut(&mut ::#_name),
-                            }
-                        } else {
-                            quote! {
-                                #name: ::#krate::Static::ref_mut(::#_name.as_mut()),
-                            }
-                        });
-                    }
-                }
-            }
-
-            if needs_reexport {
-                let rname = Ident::new(format!("_{}Resources", name));
-                root.push(quote! {
                     #[allow(non_camel_case_types)]
-                    #[allow(non_snake_case)]
+                    pub struct #rname { _0: PhantomData<*const ()> }
-                    pub struct #rname<#lifetime> {
+                });
-                        #(#fields)*
+
+                root.push(quote! {
+                    #[allow(unsafe_code)]
+                    unsafe impl #krate::Resource for #tname::#rname {
+                        type Data = #ty;
+
+                        fn borrow<'cs>(&'cs self, t: &'cs Threshold) -> &'cs Self::Data {
+                            assert!(t.value() >= #ceiling);
+
+                            unsafe { &#_static }
+                        }
+
+                        fn borrow_mut<'cs>(
+                            &'cs mut self,
+                            t: &'cs Threshold,
+                        ) -> &'cs mut Self::Data {
+                            assert!(t.value() >= #ceiling);
+
+                            unsafe { &mut #_static }
+                        }
+
+                        fn claim<R, F>(&self, t: &mut Threshold, f: F) -> R
+                        where
+                            F: FnOnce(&Self::Data, &mut Threshold) -> R
+                        {
+                            unsafe {
+                                #krate::claim(
+                                    &#_static,
+                                    #ceiling,
+                                    #device::NVIC_PRIO_BITS,
+                                    t,
+                                    f,
+                                )
+                            }
+                        }
+
+                        fn claim_mut<R, F>(&mut self, t: &mut Threshold, f: F) -> R
+                        where
+                            F: FnOnce(&mut Self::Data, &mut Threshold) -> R
+                        {
+                            unsafe {
+                                #krate::claim(
+                                    &mut #_static,
+                                    #ceiling,
+                                    #device::NVIC_PRIO_BITS,
+                                    t,
+                                    f,
+                                )
+                            }
+                        }
                     }
                 });
 
-                items.push(quote! {
+                if ceiling <= task.priority {
-                    pub use ::#rname as Resources;
+                    root.push(quote! {
+                        #[allow(unsafe_code)]
+                        impl core::ops::Deref for #tname::#rname {
+                            type Target = #ty;
+
+                            fn deref(&self) -> &Self::Target {
+                                unsafe { &#_static }
+                            }
+                        }
+
+                        #[allow(unsafe_code)]
+                        impl core::ops::DerefMut for #tname::#rname {
+                            fn deref_mut(&mut self) -> &mut Self::Target {
+                                unsafe { &mut #_static }
+                            }
+                        }
+                    })
+                }
+
+                fields.push(quote! {
+                    pub #rname: #rname,
                 });
-            } else {
+
-                items.push(quote! {
+                exprs.push(quote! {
-                    #[allow(non_snake_case)]
+                    #rname: #rname { _0: PhantomData },
-                    pub struct Resources<#lifetime> {
-                        #(#fields)*
-                    }
                 });
             }
 
+            items.push(quote! {
+                #[allow(non_snake_case)]
+                pub struct Resources {
+                    #(#fields)*
+                }
+            });
+
             items.push(quote! {
                 #[allow(unsafe_code)]
-                impl<#lifetime> Resources<#lifetime> {
+                impl Resources {
                     pub unsafe fn new() -> Self {
                         Resources {
                             #(#exprs)*
@@ -564,7 +574,7 @@ fn tasks(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
         let mut exprs = vec![];
 
         let priority = task.priority;
-        if needs_threshold {
+        if has_resources {
             tys.push(quote!(&mut #krate::Threshold));
             exprs.push(quote! {
                 &mut if #priority == 1 << #device::NVIC_PRIO_BITS {
@@ -576,18 +586,18 @@ fn tasks(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
         }
 
         if has_resources {
-            tys.push(quote!(#name::Resources));
+            tys.push(quote!(#tname::Resources));
-            exprs.push(quote!(#name::Resources::new()));
+            exprs.push(quote!(#tname::Resources::new()));
         }
 
         let path = &task.path;
-        let _name = Ident::new(format!("_{}", name));
+        let _tname = Ident::new(format!("_{}", tname));
-        let export_name = Lit::Str(name.as_ref().to_owned(), StrStyle::Cooked);
+        let export_name = Lit::Str(tname.as_ref().to_owned(), StrStyle::Cooked);
         root.push(quote! {
             #[allow(non_snake_case)]
             #[allow(unsafe_code)]
             #[export_name = #export_name]
-            pub unsafe extern "C" fn #_name() {
+            pub unsafe extern "C" fn #_tname() {
                 let f: fn(#(#tys,)*) = #path;
 
                 f(#(#exprs,)*)
@@ -597,7 +607,9 @@ fn tasks(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
         root.push(quote!{
             #[allow(non_snake_case)]
             #[allow(unsafe_code)]
-            mod #name {
+            mod #tname {
+                use core::marker::PhantomData;
+
                 #[allow(dead_code)]
                 #[deny(const_err)]
                 const CHECK_PRIORITY: (u8, u8) = (

src/lib.rs

@@ -84,7 +84,7 @@ extern crate untagged_option;
 
 use core::u8;
 
-pub use rtfm_core::{Resource, Static, Threshold};
+pub use rtfm_core::{Resource, Threshold};
 pub use cortex_m::asm::{bkpt, wfi};
 pub use cortex_m_rtfm_macros::app;
 #[doc(hidden)]

tests/cfail/init-resource-share-idle.rs

@@ -0,0 +1,31 @@
+#![deny(warnings)]
+#![feature(proc_macro)]
+#![no_std]
+
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f103xx;
+
+use rtfm::app;
+
+app! { //~ proc macro panicked
+    device: stm32f103xx,
+
+    resources: {
+        static BUFFER: [u8; 16] = [0; 16];
+    },
+
+    init: {
+        resources: [BUFFER],
+    },
+
+    idle: {
+        // ERROR resources assigned to `init` can't be shared with `idle`
+        resources: [BUFFER],
+    },
+}
+
+fn init(_p: init::Peripherals, _r: init::Resources) {}
+
+fn idle(_r: init::Resources) -> ! {
+    loop {}
+}

tests/cfail/init-resource-share-task.rs

@@ -0,0 +1,36 @@
+#![deny(warnings)]
+#![feature(proc_macro)]
+#![no_std]
+
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f103xx;
+
+use rtfm::app;
+
+app! { //~ proc macro panicked
+    device: stm32f103xx,
+
+    resources: {
+        static BUFFER: [u8; 16] = [0; 16];
+    },
+
+    init: {
+        resources: [BUFFER],
+    },
+
+    tasks: {
+        SYS_TICK: {
+            path: sys_tick,
+            // ERROR resources assigned to `init` can't be shared with tasks
+            resources: [BUFFER],
+        },
+    },
+}
+
+fn init(_p: init::Peripherals) {}
+
+fn idle() -> ! {
+    loop {}
+}
+
+fn sys_tick() {}

tests/cfail/lock.rs

@@ -45,22 +45,24 @@ fn idle() -> ! {
 }
 
 fn exti0(mut t: &mut Threshold, mut r: EXTI0::Resources) {
+    // ERROR need to lock to access the resource because priority < ceiling
+    if *r.ON {
+        //~^ error type `EXTI0::ON` cannot be dereferenced
+    }
+
     // OK need to lock to access the resource
-    if r.ON.claim(&mut t, |on, _| **on) {}
+    if r.ON.claim(&mut t, |on, _| *on) {}
 
     // OK can claim a resource with maximum ceiling
-    r.MAX.claim_mut(&mut t, |max, _| **max += 1);
+    r.MAX.claim_mut(&mut t, |max, _| *max += 1);
 }
 
 fn exti1(mut t: &mut Threshold, r: EXTI1::Resources) {
-    // ERROR no need to lock. Has direct access because priority == ceiling
+    // OK to directly access the resource because priority == ceiling
-    if (**r.ON).claim(&mut t, |on, _| **on) {
+    if *r.ON {}
-        //~^ error no method named `claim` found for type
-    }
 
-    if **r.ON {
+    // though the resource can still be claimed -- the claim is a no-op
-        // OK
+    if r.ON.claim(&mut t, |on, _| *on) {}
-    }
 }
 
 fn exti2(_t: &mut Threshold, _r: EXTI2::Resources) {}

tests/cfail/token-transfer.rs

@@ -9,7 +9,7 @@ extern crate stm32f103xx;
 
 use rtfm::{app, Threshold};
 
-app! { //~ error bound `rtfm::Threshold: core::marker::Send` is not satisfied
+app! { //~ error bound `*const (): core::marker::Send` is not satisfied
     device: stm32f103xx,
 
     resources: {