| |_call the function in a closure: `|| unsafe { /* code */ }`
| required by a bound introduced by this call
|
- = help: the trait `Fn<(proc_macro::TokenStream,)>` is not implemented for `unsafe extern "C" fn(i32, u32) -> u32 {foo}`
+ = help: the trait `Fn<(proc_macro::TokenStream,)>` is not implemented for fn item `unsafe extern "C" fn(i32, u32) -> u32 {foo}`
= note: unsafe function cannot be called generically without an unsafe block
note: required by a bound in `ProcMacro::custom_derive`
--> $SRC_DIR/proc_macro/src/bridge/client.rs:LL:COL