Build error 'identifier appears more than once in list' after update to rust 1.50

[andrey-shigantsov]

Hi.

I get this error when I use my macro to generate the rtic::app structure.

If I expand the code of my macro only with cargo expand and compile it, it works on rust v 1.50 too.

Rolling back to rust v 1.46 has solved this problem for me.

But I want use latest rust.

[korken89]

Hi,

What version of RTIC are you using?
I am using 0.5 and 0.6 alpha on latest Rust without issues.

Could you provide a minimal reproducible example as well?

[andrey-shigantsov]

I an using 0.5.6.

I will try to reproduce this error with a minimal example.

[korken89]

Thanks!
Have you tried to do a cargo clean so its not something as simple as weird artifacts hanging around?

[andrey-shigantsov]

rtic-platform.tar.gz

rasaro rtic-platform $ cargo +stable build --example "usart-drv"
   Compiling qemu-board-example v0.1.0 (/home/rasaro/Development/sandbox/tmp/rtic-platform/example-board/qemu-board)
   Compiling cortex-m-rtic-platform v0.1.0 (/home/rasaro/Development/sandbox/tmp/rtic-platform)
error: identifier appears more than once in list
  --> examples/usart-drv.rs:25:1
   |
25 | / rtic_app! {
26 | |     [resources]
27 | |     {
28 | |         usart_drv_counter: i8 = 0,
...  |
87 | |     task_irqs(TIMER_0A, TIMER_0B);
88 | | }
   | |_^
   |
   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error

error: could not compile `cortex-m-rtic-platform`

rasaro rtic-platform $ cargo +1.46 build --example "usart-drv"
   Compiling qemu-board-example v0.1.0 (/home/rasaro/Development/sandbox/tmp/rtic-platform/example-board/qemu-board)
   Compiling cortex-m-rtic-platform v0.1.0 (/home/rasaro/Development/sandbox/tmp/rtic-platform)
    Finished dev [unoptimized + debuginfo] target(s) in 0.63s

[andrey-shigantsov]

cargo clean does not help

[korken89]

Hi, from what I can see this is not an error from RTIC, but the macro.
Could you try doing this without the rtic_app macro?

I have no idea how this framework of yours works unfortunately.

The error originates from src/macros.rs:604.

[andrey-shigantsov]

I have not found an error in the macro.

src/macros.rs:604 I know that. I use RUSTFLAGS="-Z macro-backtrace" cargo +nightly build for debug my macros.

cargo expand code works: I expand this code, paste it instead of rtic_app and then builds successfully.

[andrey-shigantsov]

At rust 1.46 this works well. What could have changed in rust >1.46?

[AfoHT]

Just to clarify, with

• Rust 1.46: Works
• Rust 1.47: ?
• Rust 1.48: ?
• Rust 1.49: ?
• Rust 1.50: Broken
  Did I understand you correctly?

Tried the versions with a question mark?, could be helpful for narrowing down which version introduce a change causing breakage for you.

Just speculation, could it be the two stage macro execution somehow having changed? First your macro and then RTIC-macro would be the expected order.

[andrey-shigantsov]

Rust 1.46: Works
Rust 1.47: Broken
Rust 1.48: Broken
Rust 1.49: Broken
Rust 1.50: Broken

[andrey-shigantsov]

https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1470-2020-10-08:

It seems because of this: "Added changes to how proc-macros are expanded in macro_rules! that should help to preserve more span information."

[AfoHT]

The error message originates from here or here.

Looking at the code it is unhappy about having multiple identical identifiers, however it is unclear if it is resources or "ident" (line 158 or line 140) since the error message is identical.

Unfamiliar with your framework, do you think there's some name collision or such?

This is what I get when running it with macro-backtrace:

~/downloads/rtic-platform-error is 📦 v0.1.0 via R v1.53.0-nightly
❯ env RUSTFLAGS="-Z macro-backtrace" cargo build --example "usart-drv"
   Compiling cortex-m-rtic-platform v0.1.0 (/home/henrik/downloads/rtic-platform-error)
error: identifier appears more than once in list
   --> /home/henrik/downloads/rtic-platform-error/src/macros.rs:604:25
    |
75  |         macro_rules! rtic_app_item {
    |  _______-
    | |_______|
    | |_______|
    | |_______|
    | |_______|
    | |
76  | |
77  | |           (// FINISH
78  | |               $hw_rs_cb:ident,
...   |
394 | /               rtic_app_item!($hw_rs_cb,
395 |                     ($($ztt)*),
396 |                     (
397 |                         $($tt)*
...
421 |                     $($end_tt)*
422 | |               );
    | |________________- in this macro invocation (#4)
...
449 | /               rtic_app_item! (
450 |                     platform_hw_ph_cb,
451 |                     ($($ztt)*),
452 |                     (
...
465 |                     $($end_tt)*
466 | |               );
    | |________________- in this macro invocation (#3)
...
494 | /               rtic_app_item!($hw_rs_cb,
495 |                     ($($ztt)*),
496 |                     ($($tt)*),
497 |                     ($($zrs_tt)*),
...
513 |                     $($end_tt)*
514 | |               );
    | |________________- in this macro invocation (#5)
...
526 | /               $hw_rs_cb!($rs_src_hw: rtic_app_item ($hw_rs_cb,
527 |                     ($($ztt)*),
528 |                     (
529 |                         [$src_name($($src_meta_tt)*)]
...
532 |                     $($end_tt)*
533 | |               ));
    | |_________________- in this macro invocation (#6)
...
604 | |                               $rs_task_name,
    | |                               ^^^^^^^^^^^^^
...   |
752 | |           };
753 | |       }
    | |       -
    | |_______|
    | |_______in this expansion of `rtic_app_item!` (#2)
    | |_______in this expansion of `rtic_app_item!` (#3)
    | |_______in this expansion of `rtic_app_item!` (#4)
    | |_______in this expansion of `rtic_app_item!` (#5)
    |         in this expansion of `rtic_app_item!` (#7)
...
765 | /       macro_rules! rtic_app {
766 |             ( $($tt:tt)* ) => {
767 |                 rtic_app_item!(
    |  _______________-
768 | |                   ( ), ($($tt)*), ( ), ([ ]| |( )){ ( ),( ),( ) }, ([ ]|_cx|( )){(|_byte, _force|{ }),(),()}
769 | |               );
    | |________________- in this macro invocation (#2)
770 |             };
771 | |       }
    | |_______- in this expansion of `rtic_app!` (#1)
    |
   ::: /home/henrik/downloads/rtic-platform-error/example-board/qemu-board/src/lib.rs:27:1
    |
27  | /       macro_rules! ph_cb /* peripheral callback */ {
28  | |           (host_usart: $cb:ident ($($cb_args:tt)*)) => {
29  | |               $cb!(hw_rs: (host_usart, UART0, HOST_USART), {$($cb_args)*});
    | |               ------------------------------------------------------------- in this macro invocation (#7)
30  | |           };
31  | |       }
    | |_______- in this expansion of `platform_hw_ph_cb!` (#6)
    |
   ::: examples/usart-drv.rs:25:1
    |
25  |       / rtic_app! {
26  |       |     [resources]
27  |       |     {
28  |       |         //usart_drv_counter: i8 = 0,
...         |
87  |       |     //task_irqs(TIMER_0A, TIMER_0B);
88  |       | }
    |       |_- in this macro invocation (#1)

error: aborting due to previous error

error: could not compile `cortex-m-rtic-platform`

To learn more, run the command again with --verbose.

[andrey-shigantsov]

I think this is not a resource name collision. Because cargo expand gives a working code.

To expand the code without rtic::app I rename it in rtic_app_raw macro (src/macros.rs:4):

4c4
<         #[rtic::app(
---
>         #[xrtic::app(

This is what I get when running it with cargo expand:

rasaro rtic-platform $ cargo +nightly expand --example "usart-drv"
    Checking cortex-m-rtic-platform v0.1.0 (/home/rasaro/Development/sandbox/tmp/rtic-platform)

... some build errors ...

... some prelude ...
pub mod uart0_drv {
    use crate::board::hal;
    use crate::board::device;
    use ::cortex_m_rtic_platform::driver::usart as usart_drv;
    pub type Device = device::UART0;
    pub type HwResource = hal::usart::Usart<Device>;
    pub use usart_drv::rtic_task_handler;
    pub use usart_drv::rtic_irq_handler;
    pub type TaskResources = usart_drv::TaskResources;
    pub type IrqResources = usart_drv::IrqResources;
}
# [ xrtic :: app ( device = crate :: board :: device , peripherals = true , monotonic = :: cortex_m_rtic_platform :: rtic_time :: MonotonicTimer ) ]
const APP: () = {
    struct Resources {
        usart_drv_counter: i8,
        uart0_drv_rsx: uart0_drv::IrqResources,
        uart0_drv_rst: uart0_drv::TaskResources,
    }
    # [ init ( spawn = [ usart_test_task , uart0_drv_task ] ) ]
    fn rtic_init(cx: rtic_init::Context) -> rtic_init::LateResources {
        #[allow(unused_variables)]
        let hw_resources = hw_init(cx.core, cx.device);
        if 15 != 2_u8.pow(crate::board::device::NVIC_PRIO_BITS.into()) - 1 {
            ::core::panicking::panic("SYSTEM TIMER: priority is not max");
        }
        #[allow(unused_mut)]
        let (uart0_drv_rsx, uart0_drv_rst) = {
            let uart0_drv_rst = uart0_drv::TaskResources {};
            (uart0_drv::IrqResources {}, uart0_drv_rst)
        };
        cx.spawn.usart_test_task().unwrap();
        cx.spawn.uart0_drv_task().unwrap();
        rtic_init::LateResources {
            usart_drv_counter: 0,
            uart0_drv_rsx,
            uart0_drv_rst,
        }
    }
    # [ task ( resources = [ uart0_drv_rst , usart_drv_counter , ] , priority = 2 , capacity = 16 , spawn = [ uart0_drv_task ] , ) ]
    #[allow(unused_mut)]
    fn uart0_drv_task(mut cx: uart0_drv_task::Context) {
        let rs = cx.resources.uart0_drv_rst;
        match cx.resources.usart_drv_counter.checked_add(1) {
            Some(count) => {
                *cx.resources.usart_drv_counter = count;
            }
            None => {
                *cx.resources.usart_drv_counter = -1;
            }
        }
        uart0_drv::rtic_task_handler(rs);
    }
    # [ task ( binds = UART0 , resources = [ uart0_drv_rsx ] , spawn = [ uart0_drv_task ] , priority = 4 , ) ]
    #[allow(unused_mut)]
    fn uart0_irq(cx: uart0_irq::Context) {
        let spawn = cx.spawn;
        spawn.uart0_drv_task().unwrap();
    }
    # [ task ( priority = 1 , spawn = [ uart0_drv_task ] , schedule = [ usart_test_task ] , resources = [ usart_drv_counter ] , ) ]
    #[allow(unused_mut)]
    fn usart_test_task(mut cx: usart_test_task::Context) {
        cx.spawn.uart0_drv_task().unwrap();
        if cx.resources.usart_drv_counter.lock(|x| *x != -1) {}
    }
    extern "C" {
        fn TIMER_0A();
        fn TIMER_0B();
    }
};

If you insert this code instead of rtiс_app! {...}, then it will work with routine improvements

[AfoHT]

Any difference when testing with latest Rust and RTIC RC?

[andrey-shigantsov]

@AfoHT Trying use latest Rust and RTIC 0.6-rc.2 but got errors

   Compiling cortex-m-rtic-macros v0.6.0-rc.2 (https://github.com/rtic-rs/cortex-m-rtic.git?tag=v0.6.0-rc.2#ca9088a7)
error[E0609]: no field `shared_resource_locations` on type `&analyze::Analysis`
  --> /home/rasaro/.cargo/git/checkouts/cortex-m-rtic-da08f71f062e5e7b/ca9088a/macros/src/codegen/post_init.rs:17:21
   |
17 |         if analysis.shared_resource_locations.get(name).is_some() {
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^ unknown field
   |
   = note: available fields are: `interrupts`

error[E0609]: no field `local_resource_locations` on type `&analyze::Analysis`
  --> /home/rasaro/.cargo/git/checkouts/cortex-m-rtic-da08f71f062e5e7b/ca9088a/macros/src/codegen/post_init.rs:35:21
   |
35 |         if analysis.local_resource_locations.get(name).is_some() {
   |                     ^^^^^^^^^^^^^^^^^^^^^^^^ unknown field
   |
   = note: available fields are: `interrupts`