ICE when type not specificed for static variable (Embassy)

[perowle]

Code

#![no_std]
#![no_main]
#![deny(missing_docs, unsafe_code)]

use embassy_sync::blocking_mutex::raw::NoopRawMutex;
use embassy_sync::pubsub::{PubSubChannel };
use {defmt_rtt as _, panic_probe as _};
use embassy_executor::Spawner;

static temperature_channel = PubSubChannel::<NoopRawMutex, f32, 1, 2, 2>::new();

#[embassy_executor::main]
async fn main(spawner: Spawner) {
let p = embassy_stm32::init(Default::default());

let temp0 = temperature_channel.dyn_publisher().unwrap();

}

Meta

rustc --version --verbose:

rustc 1.79.0 (129f3b996 2024-06-10)
binary: rustc
commit-hash: 129f3b9964af4d4a709d1383930ade12dfe7c081
commit-date: 2024-06-10
host: x86_64-pc-windows-msvc
release: 1.79.0
LLVM version: 18.1.7

Error output

cargo build
    Blocking waiting for file lock on package cache
    Blocking waiting for file lock on build directory
   Compiling nucleo-f411re v0.1.0 (C:\git\rust\ec\examples\ECProto - Copy\nucleo-f411re)
error: missing type for `static` item
  --> nucleo-f411re\src/main.rs:13:27
   |
13 | static temperature_channel = PubSubChannel::<NoopRawMutex, f32, 1, 2, 2>::new();
   |                           ^ help: provide a type for the static variable: `: PubSubChannel<NoopRawMutex, f32, 1, 2, 2>`

thread 'rustc' panicked at compiler\rustc_const_eval\src\interpret\validity.rs:733:21:
assertion `left == right` failed
  left: Mut
 right: Not
stack backtrace:
   0:     0x7ffbc2eb3c48 - std::backtrace_rs::backtrace::dbghelp64::trace
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\..\..\backtrace\src\backtrace\dbghelp64.rs:91
   1:     0x7ffbc2eb3c48 - std::backtrace_rs::backtrace::trace_unsynchronized
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66
   2:     0x7ffbc2eb3c48 - std::sys_common::backtrace::_print_fmt
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\sys_common\backtrace.rs:68
   3:     0x7ffbc2eb3c48 - std::sys_common::backtrace::_print::impl$0::fmt
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\sys_common\backtrace.rs:44
   4:     0x7ffbc2ee4f09 - core::fmt::rt::Argument::fmt
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\core\src\fmt\rt.rs:165
   5:     0x7ffbc2ee4f09 - core::fmt::write
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\core\src\fmt\mod.rs:1157
   6:     0x7ffbc2eaa3e1 - std::io::Write::write_fmt<std::sys::pal::windows::stdio::Stderr>
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\io\mod.rs:1832
   7:     0x7ffbc2eb3a26 - std::sys_common::backtrace::print
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\sys_common\backtrace.rs:34
   8:     0x7ffbc2eb6b88 - std::panicking::default_hook::closure$1
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\panicking.rs:271
   9:     0x7ffbc2eb67f7 - std::panicking::default_hook
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\panicking.rs:298
  10:     0x7ffba29bfdfe - __longjmp_internal
  11:     0x7ffbc2eb71b7 - alloc::boxed::impl$50::call
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\alloc\src\boxed.rs:2036
  12:     0x7ffbc2eb71b7 - std::panicking::rust_panic_with_hook
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\panicking.rs:799
  13:     0x7ffbc2eb7047 - std::panicking::begin_panic_handler::closure$0
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\panicking.rs:664
  14:     0x7ffbc2eb45bf - std::sys_common::backtrace::__rust_end_short_backtrace<std::panicking::begin_panic_handler::closure_env$0,never$>
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\sys_common\backtrace.rs:171
  15:     0x7ffbc2eb6cf8 - std::panicking::begin_panic_handler
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\panicking.rs:652
  16:     0x7ffbc2f0d7d4 - core::panicking::panic_fmt
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\core\src\panicking.rs:72
  17:     0x7ffbc2f0dc21 - core::panicking::assert_failed_inner
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\core\src\panicking.rs:409
  18:     0x7ffba343c607 - <unicode_script[df3ac769750e1c82]::ScriptIterator as core[bd51e8c031ece540]::iter::traits::iterator::Iterator>::next
  19:     0x7ffba2205003 - <rustc_const_eval[254959616a52d48e]::interpret::eval_context::InterpCx<_>>::storage_live_dyn::is_very_trivially_sized
  20:     0x7ffba220556d - <rustc_const_eval[254959616a52d48e]::interpret::eval_context::InterpCx<_>>::storage_live_dyn::is_very_trivially_sized
  21:     0x7ffba2205470 - <rustc_const_eval[254959616a52d48e]::interpret::eval_context::InterpCx<_>>::storage_live_dyn::is_very_trivially_sized
  22:     0x7ffba2205470 - <rustc_const_eval[254959616a52d48e]::interpret::eval_context::InterpCx<_>>::storage_live_dyn::is_very_trivially_sized
  23:     0x7ffba137f4df - rustc_const_eval[254959616a52d48e]::interpret::eval_context::mir_assign_valid_types
  24:     0x7ffba2274da5 - rustc_const_eval[254959616a52d48e]::util::compare_types::relate_types
  25:     0x7ffba1385a40 - rustc_const_eval[254959616a52d48e]::const_eval::eval_queries::eval_static_initializer_provider
  26:     0x7ffba12e15c8 - <dyn std[97e236bc5ac76467]::io::Write as nu_ansi_term[46f323ea840c8206]::write::AnyWrite>::write_str
  27:     0x7ffba12ca18d - <dyn std[97e236bc5ac76467]::io::Write as nu_ansi_term[46f323ea840c8206]::write::AnyWrite>::write_str
  28:     0x7ffba1facadb - rustc_traits[df3a8b33046bddd2]::type_op::type_op_prove_predicate
  29:     0x7ffba12f7048 - rustc_query_impl[46f2cb59a7e58a2f]::query_system
  30:     0x7ffba196a9d3 - rustc_hir_analysis[d196ce244286923b]::check_crate
  31:     0x7ffba16e52c6 - <rustc_interface[5039fedd6fed528e]::passes::LintStoreExpandImpl as rustc_expand[8a362ccb6e11b5d0]::base::LintStoreExpand>::pre_expansion_lint
  32:     0x7ffba12e1f5a - <dyn std[97e236bc5ac76467]::io::Write as nu_ansi_term[46f323ea840c8206]::write::AnyWrite>::write_str
  33:     0x7ffba1257af1 - rustc_traits[df3a8b33046bddd2]::type_op::type_op_normalize_clause
  34:     0x7ffba12eaa07 - rustc_query_impl[46f2cb59a7e58a2f]::query_system
  35:     0x7ffb9e7147c2 - llvm::function_ref<void __cdecl(llvm::Value const * __ptr64)>::callback_fn<`llvm::Value::stripInBoundsOffsets'::`1'::<lambda_1_1> >
  36:     0x7ffb9e711a96 - llvm::function_ref<void __cdecl(llvm::Value const * __ptr64)>::callback_fn<`llvm::Value::stripInBoundsOffsets'::`1'::<lambda_1_1> >
  37:     0x7ffb9e7195f9 - llvm::function_ref<void __cdecl(llvm::Value const * __ptr64)>::callback_fn<`llvm::Value::stripInBoundsOffsets'::`1'::<lambda_1_1> >
  38:     0x7ffbc2ec822d - alloc::boxed::impl$48::call_once
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\alloc\src\boxed.rs:2022
  39:     0x7ffbc2ec822d - alloc::boxed::impl$48::call_once
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\alloc\src\boxed.rs:2022
  40:     0x7ffbc2ec822d - std::sys::pal::windows::thread::impl$0::new::thread_start
                               at /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library\std\src\sys\pal\windows\thread.rs:52
  41:     0x7ffc58e9257d - BaseThreadInitThunk
  42:     0x7ffc5964af28 - RtlUserThreadStart

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.79.0 (129f3b996 2024-06-10) running on x86_64-pc-windows-msvc

note: compiler flags: --crate-type bin -C opt-level=3 -C embed-bitcode=no -C codegen-units=1 -C debuginfo=2 -C debug-assertions=on -C link-arg=--nmagic -C link-arg=-Tlink.x -C link-arg=-Tdefmt.x

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [eval_static_initializer] evaluating initializer of static `temperature_channel`
#1 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `nucleo-f411re` (bin "nucleo-f411re") due to 1 previous error

Backtrace

Included above

[pacak]

Can you share a bit more info about building the project? Cargo.toml file, environment variables you need to set, etc?

[perowle]

Sorry, yeah here's the Cargo.toml contents and instructions for building at the bottom.

Cargo.toml contents:

[package]
resolver = "2"
name = "nucleo-f411re"
categories = [ "embedded", "no-std" ]
version = "0.1.0"
edition = "2021"
keywords = [ "embedded", "no-std", "embedded-hal" ]
license = "MIT"
rust-version = "1.76"

[dependencies]
embassy-stm32 = { git = "https://github.com/embassy-rs/embassy.git", rev = "128575aebe18eea29862c52a88f81671fbcbf610", features = ["defmt", "stm32f411re", "time-driver-any", "exti", "memory-x", "unstable-pac", "chrono"] }
cortex-m = { version = "0.7.7", features = ["inline-asm", "critical-section-single-core"] }
chrono = { version = "^0.4", default-features = false }
cortex-m-rt = "0.7.0"
defmt = "0.3"
defmt-rtt = "0.4"
embassy-embedded-hal = { git = "https://github.com/embassy-rs/embassy.git", rev = "128575aebe18eea29862c52a88f81671fbcbf610" }
embassy-executor = { git = "https://github.com/embassy-rs/embassy.git", rev = "128575aebe18eea29862c52a88f81671fbcbf610", features = ["task-arena-size-4096", "arch-cortex-m", "executor-thread", "defmt", "integrated-timers"] }
embassy-sync = { git = "https://github.com/embassy-rs/embassy.git", rev = "128575aebe18eea29862c52a88f81671fbcbf610" }
embassy-time = { git = "https://github.com/embassy-rs/embassy.git", rev = "128575aebe18eea29862c52a88f81671fbcbf610", features = ["defmt", "defmt-timestamp-uptime"] }
embedded-hal-async = "1.0"
panic-probe = { version = "0.3", features = ["print-defmt"] }

Command line to build:
cargo build --target thumbv7em-none-eabihf

May be needed to compile successfully:
rustup target add thumbv7em-none-eabihf

[perowle]

Regarding this issue - the simple fix is to add the type to the static variable, and rustc is happy. Just wanted to give you the backtrace in case there's other issues.

[pacak]

Compiler panics with just this

use embassy_sync::blocking_mutex::raw::NoopRawMutex;
use embassy_sync::pubsub::PubSubChannel;

static temperature_channel: _ = PubSubChannel::<NoopRawMutex, f32, 1, 2, 2>::new();

Panic and stack trace looks similar to #124164, both reproducible in current nightly

[Noratrieb]

yeah, this is a duplicate of #124164. closing as such, thank you for the report anyways.