diff --git a/macros/src/trans.rs b/macros/src/trans.rs
index 4d51840f98..ef224c1921 100644
--- a/macros/src/trans.rs
+++ b/macros/src/trans.rs
@@ -50,8 +50,8 @@ fn idle(
             .iter()
             .all(|resource| ownerships[resource].is_owned())
     {
-        tys.push(quote!(#krate::Threshold));
-        exprs.push(quote!(unsafe { #krate::Threshold::new(0) }));
+        tys.push(quote!(&mut #krate::Threshold));
+        exprs.push(quote!(unsafe { &mut #krate::Threshold::new(0) }));
     }
 
     if !app.idle.locals.is_empty() {
diff --git a/src/lib.rs b/src/lib.rs
index c1c7c8f74e..a4cfbec870 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -221,10 +221,10 @@ macro_rules! task {
         #[allow(non_snake_case)]
         #[no_mangle]
         pub unsafe extern "C" fn $NAME() {
-            let f: fn($crate::Threshold, ::$NAME::Resources) = $body;
+            let f: fn(&mut $crate::Threshold, ::$NAME::Resources) = $body;
 
             f(
-                $crate::Threshold::new(::$NAME::$NAME),
+                &mut $crate::Threshold::new(::$NAME::$NAME),
                 ::$NAME::Resources::new(),
             );
         }
@@ -240,7 +240,7 @@ macro_rules! task {
         #[no_mangle]
         pub unsafe extern "C" fn $NAME() {
             let f: fn(
-                $crate::Threshold,
+                &mut $crate::Threshold,
                 &mut $local,
                 ::$NAME::Resources,
             ) = $body;
@@ -250,7 +250,7 @@ macro_rules! task {
             };
 
             f(
-                $crate::Threshold::new(::$NAME::$NAME),
+                &mut $crate::Threshold::new(::$NAME::$NAME),
                 &mut LOCAL,
                 ::$NAME::Resources::new(),
             );
diff --git a/tests/cfail/duplicated-handler.rs b/tests/cfail/duplicated-handler.rs
index cae5d8a5e8..dc90204115 100644
--- a/tests/cfail/duplicated-handler.rs
+++ b/tests/cfail/duplicated-handler.rs
@@ -28,8 +28,8 @@ fn idle() -> ! {
 
 task!(EXTI0, exti0);
 
-fn exti0(_t: Threshold, _r: EXTI0::Resources) {}
+fn exti0(_t: &mut Threshold, _r: EXTI0::Resources) {}
 
 task!(EXTI0, exti1);
 
-fn exti1(_t: Threshold, _r: EXTI0::Resources) {}
+fn exti1(_t: &mut Threshold, _r: EXTI0::Resources) {}
diff --git a/tests/cfail/local-token.rs b/tests/cfail/local-token.rs
new file mode 100644
index 0000000000..4c98956bf0
--- /dev/null
+++ b/tests/cfail/local-token.rs
@@ -0,0 +1,44 @@
+#![deny(warnings)]
+#![feature(const_fn)]
+#![feature(proc_macro)]
+
+#[macro_use(task)]
+extern crate cortex_m_rtfm as rtfm;
+extern crate stm32f103xx;
+
+use rtfm::{app, Threshold};
+
+app! {
+    device: stm32f103xx,
+
+    tasks: {
+        EXTI0: {
+            enabled: true,
+            priority: 1,
+        },
+    }
+}
+
+fn init(_p: init::Peripherals) {}
+
+fn idle() -> ! {
+    loop {}
+}
+
+task!(EXTI0, exti0, Old {
+    token: Option<Threshold> = None;
+});
+
+fn exti0(nt: &mut Threshold, old: &mut Old, _r: EXTI0::Resources) {
+    if let Some(ot) = old.token.take() {
+        let _: (Threshold, Threshold) = (*nt, ot);
+        //~^ error cannot move out of borrowed content
+
+        return
+    }
+
+    // ERROR can't store a threshold token in a local variable, otherwise you
+    // would end up with two threshold tokens in a task (see `if let` above)
+    old.token = Some(*nt);
+    //~^ error cannot move out of borrowed content
+}
diff --git a/tests/cfail/lock.rs b/tests/cfail/lock.rs
index f93b79aa11..736027e221 100644
--- a/tests/cfail/lock.rs
+++ b/tests/cfail/lock.rs
@@ -45,7 +45,7 @@ fn idle() -> ! {
 
 task!(EXTI0, exti0);
 
-fn exti0(mut t: Threshold, r: EXTI0::Resources) {
+fn exti0(mut t: &mut Threshold, r: EXTI0::Resources) {
     // OK need to lock to access the resource
     if r.STATE.claim(&mut t, |state, _| **state) {}
 
@@ -55,7 +55,7 @@ fn exti0(mut t: Threshold, r: EXTI0::Resources) {
 
 task!(EXTI1, exti1);
 
-fn exti1(mut t: Threshold, r: EXTI1::Resources) {
+fn exti1(mut t: &mut Threshold, r: EXTI1::Resources) {
     // ERROR no need to lock. Has direct access because priority == ceiling
     if r.STATE.claim(&mut t, |state, _| **state) {
         //~^ error no method named `claim` found for type
diff --git a/tests/cfail/priority-too-high.rs b/tests/cfail/priority-too-high.rs
index ac3a7043a6..c76b7a6b68 100644
--- a/tests/cfail/priority-too-high.rs
+++ b/tests/cfail/priority-too-high.rs
@@ -26,4 +26,4 @@ fn idle() -> ! {
 
 task!(SYS_TICK, sys_tick);
 
-fn sys_tick(_: Threshold, _: SYS_TICK::Resources) {}
+fn sys_tick(_: &mut Threshold, _: SYS_TICK::Resources) {}
diff --git a/tests/cfail/priority-too-low.rs b/tests/cfail/priority-too-low.rs
index 8bb080171b..1e0c8e92be 100644
--- a/tests/cfail/priority-too-low.rs
+++ b/tests/cfail/priority-too-low.rs
@@ -26,4 +26,4 @@ fn idle() -> ! {
 
 task!(SYS_TICK, sys_tick);
 
-fn sys_tick(_: Threshold, _: SYS_TICK::Resources) {}
+fn sys_tick(_: &mut Threshold, _: SYS_TICK::Resources) {}
diff --git a/tests/cfail/token-outlive.rs b/tests/cfail/token-outlive.rs
index 9bcd288260..93d1c604f9 100644
--- a/tests/cfail/token-outlive.rs
+++ b/tests/cfail/token-outlive.rs
@@ -38,7 +38,7 @@ fn idle() -> ! {
 
 task!(EXTI0, exti0);
 
-fn exti0(mut t: Threshold, r: EXTI0::Resources) {
+fn exti0(mut t: &mut Threshold, r: EXTI0::Resources) {
     // ERROR token should not outlive the critical section
     let t = r.STATE.claim(&mut t, |_state, t| t);
     //~^ error cannot infer an appropriate lifetime
@@ -46,4 +46,4 @@ fn exti0(mut t: Threshold, r: EXTI0::Resources) {
 
 task!(EXTI1, exti1);
 
-fn exti1(_t: Threshold, _r: EXTI1::Resources) {}
+fn exti1(_t: &mut Threshold, _r: EXTI1::Resources) {}
diff --git a/tests/cfail/token-transfer.rs b/tests/cfail/token-transfer.rs
index e517a6bf49..91e74bdf38 100644
--- a/tests/cfail/token-transfer.rs
+++ b/tests/cfail/token-transfer.rs
@@ -32,4 +32,4 @@ fn idle() -> ! {
 
 task!(EXTI0, exti0);
 
-fn exti0(_t: Threshold, _r: EXTI0::Resources) {}
+fn exti0(_t: &mut Threshold, _r: EXTI0::Resources) {}
diff --git a/tests/cfail/wrong-threshold.rs b/tests/cfail/wrong-threshold.rs
index af8bb05d73..39d3a57b52 100644
--- a/tests/cfail/wrong-threshold.rs
+++ b/tests/cfail/wrong-threshold.rs
@@ -39,7 +39,7 @@ fn idle() -> ! {
 
 task!(EXTI0, exti0);
 
-fn exti0(mut ot: Threshold, r: EXTI0::Resources) {
+fn exti0(mut ot: &mut Threshold, r: EXTI0::Resources) {
     r.A.claim(&mut ot, |_a, mut _it| {
         //~^ error cannot borrow `ot` as mutable more than once at a time
         //~| error cannot borrow `ot` as mutable more than once at a time
@@ -50,4 +50,4 @@ fn exti0(mut ot: Threshold, r: EXTI0::Resources) {
 
 task!(EXTI1, exti1);
 
-fn exti1(_t: Threshold, r: EXTI1::Resources) {}
+fn exti1(_t: &mut Threshold, r: EXTI1::Resources) {}