make resource proxies not Sync

macros/src/trans.rs

@@ -440,8 +440,6 @@ fn resources(app: &App, ownerships: &Ownerships, root: &mut Vec<Tokens>) {
                     #[allow(non_camel_case_types)]
                     pub struct #name { _0: PhantomData<*const ()> }
 
-                    unsafe impl Sync for #name {}
-
                     #[allow(unsafe_code)]
                     impl #name {
                         pub unsafe fn new() -> Self {

tests/cfail/resource-not-send-sync.rs

@@ -41,8 +41,9 @@ fn is_send<T>(_: &T) where T: Send {}
 fn is_sync<T>(_: &T) where T: Sync {}
 
 fn exti0(_t: &mut Threshold, r: EXTI0::Resources) {
-    // OK
+    // ERROR resource proxies can't be shared between tasks
     is_sync(&r.SHARED);
+    //~^ error the trait bound `*const (): core::marker::Sync` is not satisfied
 
     // ERROR resource proxies are not `Send`able across tasks
     is_send(&r.SHARED);